Hydraulics. Chapter 6

Transcription

1 Chapter Hydraulics Specifications Test Specifications Repair Specifications Hydraulic Hose, Tube, and Fitting General Instructions O-Ring Installation Hydraulic Hose Installation Hydraulic Service Tools Portable In-Line Filter Digital Hydraulic Tester Hydraulic Flow Meter Digital Pressure Gauge Kit Hydraulic Hose Kit Hydraulic Test Fitting Kit Blocking Disk Set Component Location Hydraulic Schematic Theory of Operation and Diagnostic Information Steering Circuit Schematic and Theory of Operation Steering Circuit Schematic Raise Circuit Schematic and Theory of Operation Raise Circuit Schematic Lower Circuit Schematic and Theory of Operation Lower Circuit Schematic Mow Circuit (On) Schematic and Theory of Operation Mow Circuit (On) Schematic Backlap Circuit Schematic and Theory of Operation Backlap Circuit Schematic Field Test Procedures Preliminary s Lift Cylinder Leakage Test Steering Leakage Test Reel Motor Case Drain Test Rev B -

2 Instrument Test Procedures Instrument Test Overview Front Cutting Units Circuit Test Front Cutting Units Pump Test Front Reel Test Front Reel Motors Test Rear Cutting Units Circuit Test Rear Cutting Units Pump Test Rear Reel Test Rear Reel Motors Test Lift/Steering Relief Pressure Test Lift/Steering Relief Adjustment Lower Relief Pressure Test Lift/Steer Pump Test Repair Hydraulic Oil Tank Drain Procedure Gear Pump Lift Rear Reel Front Reel Hydraulic Oil Return Filter Assembly Hydraulic Oil Charge Filter Assembly Rear Lift Cylinders Center Lift Cylinder Left and Right Front Lift Cylinders Hydraulic Oil Tank Hydraulic Oil Cooler Rev B

3 Specifications Test Specifications Specifications Front Cutting Units Pump Flow gpm (lpm).8 (25.7) at 350 rpm Rear Cutting Units Pump Flow gpm (lpm).8 (25.7) at 350 rpm Lift/Steer Pump Flow gpm (lpm).8 (25.7) at 350 rpm Hydraulic Leakage Percentage Ranges 0 0% = Good 20% = Marginal 2% and Beyond = Bad Lift/Steering Relief Pressure Setting psi (bar) 450 ± 0% (00 ± 0%) Lower Relief Pressure Setting psi (bar) 450 ± 0% (3 ± 0%) Reel Motor Forward Relief Pressure Setting psi (bar) 7 ± 0% (8 ± 0%) Reel Motor Reverse Relief Pressure Setting psi (bar) 7 ± 0% (8 ± 0%) Reel Motor Case Drain Rate Less than pint (0.47 L) per minute Rev B -3

4 Repair Specifications Specifications Gear Pump Rear Cover-to-Pump Body Bolt Torque lb-ft (N m) 33 (45) Gear Pump Test Fitting Torque lb-ft (N m) 32.9 (44.) Gear Pump Tee Fitting Torque lb-ft (N m) 55 (74.) Gear Pump Outlet Port Fitting Torque lb-ft (N m) 55 (74.) Gear Pump Inlet Port Fitting Torque lb-ft (N m) 32.9 (44.) Lift Coil Nut Torque lb-ft (N m) 0 (3.5) Lift Relief Torque lb-ft (N m) 24 2 ( ) Lift Torque lb-ft (N m) 9 2 ( ) Lift Port P and Front Side Port T Fitting lb-ft (N m) 0 (8.4) Torque Lift Port G Fitting Torque lb-ft (N m) 7 (23) Lift Ports, 2, 3, 8, 9, and 0 Fitting lb-ft (N m) 7 (23) Torque Lift Ports 4 and Fitting and One-Way lb-ft (N m) 7 (23) Restrictor Torque Lift Rear Side Port T Fitting Torque lb-ft (N m) 0 (8.4) Reel Coil Nut Torque lb-ft (N m) 0 (3.5) Reel Flow Control Torque lb-ft (N m) 24 2 ( ) Reel Ports A and B Fitting Torque lb-ft (N m) 0 (8.4) Reel Port G Fitting Torque lb-ft (N m) 7 (23) Reel Port P Elbow Fitting Torque lb-ft (N m) 80 (08.5) Reel Port T Fitting Torque lb-ft (N m) 0 (8.4) Hydraulic Oil Tank Capacity gal (L) 4 (53) Center and Rear Lift Cylinder Rod Nut Torque lb-ft (N m) 50 (7.8) Left and Right Front Cylinder Rod Nut Torque lb-ft (N m) 50 (7.8) Rev B

5 Hydraulic Hose, Tube, and Fitting General Instructions O-Ring Installation Always install new O-rings. On hoses with O-ring fittings, make sure O-rings are properly seated before tightening. O-rings should be lubricated with the fluid to be used in the system prior to assembly. Boss Fitting O-Ring Installation 3 TN4075 Tubing O.D. or Hose I.D. 2 O-Ring 3 Thread Size O-Ring Seal Kits SAE Boss O-Ring Kit Jacobsen PN O-Ring Face Seal (ORS) O-Ring Kit PN Common O-Ring Sizes Kit PN Replacement O-Rings for ORS (Face Seal) Fittings ORS (Face Seal) Tube Size ORS (Face Seal) O-Ring Size Jacobsen Part Number TN4097 Replacement O-Rings for O-Ring Boss Fittings Tubing O.D. or Hose I.D. Thread Size Hydraulic Hose Installation Jacobsen Part Number /8 5/ / 3/ /4 7/ / / /8 9/ /2 3/ /8 7/ /4 -/ /8-3/ / /4-5/ /2-7/ / Hold the fixed portion of the hose coupling with one wrench; use a second wrench to tighten or loosen the hose nut. This will avoid damaging the fitting seal. When tightening a hose, do not permit the hose to twist; hold the hose in a normal straight position. When installing hoses, place fittings at angles to avoid contact with fixed parts when turning. Make sure hoses are assembled to proper A and B ports on components. Hydraulic Hose and Tube Torque Values Size lb-ft N m Dash Fractional Min Max Min Max -4 / / / / / / / Rev B -5

6 Hydraulic Service Tools The hydraulic service tools listed here can be obtained from K-Line Industries at Digital Hydraulic Tester Part Number AT4003 Portable In-Line Filter Part Number JAC5097 TN4288 When hydraulic components fail internally, debris from the failed component can spread throughout the hydraulic system and cause additional damage. This situation can be magnified when dealing with a closed-loop traction system, where oil is not filtered. In the event of a traction system component failure, it is recommended that all traction system components be disassembled and cleaned, or filtered using a portable in-line filter available through your Jacobsen Dealer. The portable in-line filter should also be used when testing hydraulic systems or after replacing a failed component. IMPORTANT TN428 Always install the in-line filter so oil flows through the filter before entering a component. Once filtering has begun, never reverse the flow of oil, or debris will re-enter the system. Features Flow up to 00 gpm (379 lpm) Pressure up to 000 psi (44 bar) Temperature up to 250 F (20 C) Digital display for flow and temperature Analog display for pressure Flow accuracy % of full scale Hydraulic Flow Meter Part Number AT40002 TN4287 Features Glycerin filled pressure gauge Precision needle-type load valve 4 40 gpm (5 5 lpm) flow range Pressure up to 5000 psi (345 bar) -2 port size Rev B

7 Digital Pressure Gauge Kit Part Number JAC50 Hydraulic Test Fitting Kit Part Number JAC500A Features Quick disconnect fittings Pressure up to 5000 psi (345 bar) Includes one 5 ft (52 cm) hose Hydraulic Hose Kit Part Number JAC500H This hydraulic hose kit is intended to be used with the JAC500A Hydraulic Test Fitting Kit. Contents TN4290 Two 8 ft (244 cm) 2 ORFS (F) x 0 ORFS (F) hoses Four 8 ft (244 cm) 0 ORFS (F) x 0 ORFS (F) hoses Two 8 ft (244 cm) 8 ORFS (F) x 0 ORFS (F) hoses For detailed component descriptions and sizes, please see the K-Line Industries website at Contents Twenty ORFS tee fittings in five sizes Eight ORFS 90 elbow fittings in four sizes Forty ORFS caps in five sizes Forty ORFS plugs in five sizes Six ORS reducer adapters in three sizes Sixteen ORS adapters in four sizes Eight blocking disks in four sizes Three JIC tee fittings in three sizes Three 4 in. (02 mm) jumper hoses in three sizes One ORS/male NPTF adapter One vented bushing One copper tube assembly Blocking Disk Set Part Number JAC500- TN4289 This blocking disk set is part of the JAC500A Hydraulic Test Fitting Kit. Contents Two - blocking disks Two -8 blocking disks Two -0 blocking disks Two -2 blocking disks Two - blocking disks Rev B -7

8 Component Location See Figure TN358, TN328, TN3590, TN349 Gear Pump 4 Return Filter Assembly 7 Front Reel 0 Center Lift Cylinder 2 Radiator/Hydraulic Oil Cooler 5 Hydraulic Oil Tank 8 Lift Right Lift Cylinder 3 Charge Pressure Filter Rear Lift Cylinder 9 Left Lift Cylinder 2 Rear Reel Figure -: Component Location Left Side Rev B

9 Page Intentionally Blank Rev B -9

10 Hydraulic Schematic See Figures -2 through -. REV Test Port M2 B ±50 rpm 2.8 ci Reverse Relief 325 psi 0.50 ci Gear Pump 0.50 ci 0.50 ci STRG Test Port Tow Forward Relief (See Note) 3 2 M5 M in. Traction Pump 0.03 in. A Screen 40 Mesh L2 Control Sleeve Charge Pressure Relief 35 psi M3 0 Micron Filter EDC L FOW Test Port M 25 psi Switch 25 psi Crack Bypass Charge Filter Micron Filter 25 psi Crack Bypass Return Filter 9 Tank Fill Cap Assembly Oil Cooler 25 psi Crack Bypass Suction Screen 00 Mesh 0 Micron Filter Hydraulic Tank Note: Forward relief valve pressure is 325 psi for machines with serial numbers ending 5 through Forward relief valve pressure is 4350 psi for machines with serial numbers ending 2500 and up. Figure -2 TN Rev B

11 Hydraulic Schematic, Continued 2 Reverse Left Front Wheel Motor Right Front Wheel Motor (See Note) Brake Cylinder Brake Cylinder (See Note) RF REV LF RF Relief 400 psi Forward 4WD LF Relief 400 Hot Oil Shuttle DRN RRR in. RRF LRF LRR RRF LRF Right Rear Wheel Motor.90 ci.90 ci Left Rear Wheel Motor DRN Relief 350 psi BR Brake Release ST 0 Brake Solenoid CHG 4 5 Note: Front wheel motor displacement is 9.23 ci for machines with serial numbers ending 5 through Front wheel motor displacement is 7.09 ci for machines with serial numbers ending 2500 and up. Figure -3 TN Rev B -

12 Hydraulic Schematic, Continued 7 P T E Relief 450 psi 2 Steering Unit 3.90 ci Steering L R 7 8 Steering Cylinder Figure -4 TN Rev B

13 Hydraulic Schematic, Continued 7 7 Lift/Lower Test Port G Lift P Solenoid 2 T T Lower Relief 450 psi in in in in in in in. 8 One-Way Restrictor in in. Left Front Cylinder Center Cylinder Left Rear Cylinder Right Rear Cylinder Right Front Cylinder in Figure -5 TN Rev B -3

14 Hydraulic Schematic, Continued RF Reel Motor C Reel Motor LF Reel Motor 7 Reverse Relief 7 psi Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi Forward Relief 7 psi RR Reel Motor LR Reel Motor Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi A B A B Solenoid Backlap Solenoid Backlap Rear Reel Test Port G Rear Reel Front Reel Test Port G Front Reel P T P T Figure - TN Rev B

15 Page Intentionally Blank Rev B -5

16 Theory of Operation and Diagnostic Information Steering Circuit Schematic and Theory of Operation System Conditions: Engine running Steering wheel turned to the right or left (left turn shown) Oil Supply to Steering Unit Hydraulic oil is drawn from the hydraulic oil tank by section of the gear pump assembly. Before entering the gear pump assembly, the inlet oil is filtered by a 00-mesh screen to remove any debris. Operating pressure oil from section of the three-section gear pump is routed to port P of the steering unit. Steering Circuit Operating pressure oil enters the steering unit at port P, and is routed to the pilot line of the 450 psi (00 bar) relief valve, against the relief valve and check valve, and to the steering valve. With the steering wheel in the neutral (straight ahead) position, the steering valve routes all of the operating pressure oil out of the steering unit through port E, supplying operating pressure oil to the lift valve. With the steering wheel turned to the left, the steering valve is moved, allowing oil to flow through the valve to the gerotor metering section. Oil is then routed through port L of the steering unit to the piston side of the steering cylinder, extending the rod, and moving the rear wheels in the desired direction. Oil from the rod end of the steering cylinder flows back into the steering unit through port R, through the steering valve, and through port T. Oil exiting the steering unit is routed through the lift valve and then returns to the hydraulic tank. Oil from the rod end of the steering cylinder is also routed to port ST of the park brake release valve. When the park brake release valve (lever) is in the normal position, oil is blocked. Circuit Relief The steering system is protected by the 450 psi (00 bar) relief valve. If the pressure on the pilot line of the relief valve reaches 450 psi (00 bar), the valve will open, dumping operating pressure oil through port T of the lift valve to the hydraulic tank Rev B

17 Steering Circuit Schematic See Figure P T E Relief 450 psi Steering Unit 3.90 ci Steering L R Steering Cylinder 4 Operating Pressure Oil Metered Oil Return Oil Operating Pressure Oil from Gear Pump (Section ) 3 Return Oil to Lift (Port T) 2 Operating Pressure Oil to Lift (Port P) 4 Return Oil to Park Brake Release (Port ST) Figure -7 TN Rev B -7

18 Raise Circuit Schematic and Theory of Operation System Conditions: Engine running at fast idle Mower raise/lower switch in the raise position The cutting unit motors will automatically shut off as the cutting units are raised. Oil Supply to the Lift Hydraulic oil is drawn from the hydraulic oil tank by section of the gear pump assembly. Before entering the gear pump assembly, the inlet oil is filtered by a 00-mesh screen to remove any debris. Operating pressure oil from section of the gear pump is routed through the steering unit. The steering unit will supply oil flow to the lift valve via port E. Raise Circuit Operating pressure oil supplied by section of the gear pump enters the lift valve at port P. The oil flows through the solenoid valve, check valves, and in. ( mm) orifices to the rod side of the front and center lift cylinders. Oil also flows unrestricted through the 0.02 in. (0. mm) one-way restrictor to the rod side of the rear lift cylinders. Oil flow to the rod side of the lift cylinders raises the cutting units. Oil from the piston end of the front and center lift cylinders flows through the in. ( mm) orifices and back to the return filter, oil cooler, then hydraulic tank. Oil from the piston end of the rear lift cylinders flows through the in. (.4 mm) orifice and back to the hydraulic tank. The orifice restricts the flow of oil, dampening the reaction of the cylinder retraction. Circuit Relief The lift system is protected by the 450 psi (00 bar) relief valve in the steering unit. If the pressure on the pilot line of the relief valve reaches 450 psi (00 bar), the valve will open, dumping operating pressure oil through port T of the lift valve to the return filter, oil cooler, and then the hydraulic tank Rev B

19 Raise Circuit Schematic See Figure -8. Lift/Lower Test Port G Lift P Solenoid 2 3 T T Lower Relief 450 psi in in in in in in in. One-Way Restrictor in in. Left Front Cylinder Center Cylinder Left Rear Cylinder Right Rear Cylinder Right Front Cylinder in. Operating Pressure Oil Metered Oil Return Oil Operating Pressure Oil from Steering Unit (Port E) 3 Return Oil to Hydraulic Tank 2 Return Oil from Steering Unit (Port T) Figure -8 TN Rev B -9

20 Lower Circuit Schematic and Theory of Operation System Conditions: Engine running Mower raise/lower switch in the lower position Oil Supply to Lift Hydraulic oil is drawn from the hydraulic oil tank by section of the gear pump assembly. Before entering the gear pump assembly, the inlet oil is filtered by a 00-mesh screen to remove any debris. Operating pressure oil from section of the gear pump is routed through the steering unit. The steering unit will supply oil flow to the lift valve via port E. Lower Circuit Operating pressure oil supplied by section of the gear pump enters the lift valve at port P. The oil flows through the solenoid valve to the pilot lines of the check valves, the 450 psi (3 bar) relief valve, and through the in. ( mm) orifices to the piston side of the front and center lift cylinders. Oil also flows through the in. (.4 mm) orifice to the piston side of the rear lift cylinders. The 450 psi (3 bar) relief valve allows sufficient pressure to build up to unseat the check valves. Once that pressure is satisfied, the relief valve will shift, dumping excess oil to the return filter, oil cooler, and then the hydraulic tank. With operating pressure oil at the pilot lines of the check valves, the check valves open. Gravity allows the cutting units to lower, pulling against the lift cylinders. Oil from the rod end of the front and center lift cylinders flows through the in. ( mm) orifices, which dampen the lowering of the reels to prevent damage to the cutting units, and then flows through the check valves, and back to the hydraulic tank. Oil from the rod end of the rear lift cylinders flows through the 0.02 in. (0. mm) one-way restrictor, which lowers the rear cutting units at a slightly slower rate than the front cutting units, then flows through the check valve, and back to the hydraulic tank. Circuit Relief The lower system is protected by the 450 psi (3 bar) relief valve. If the pressure on the pilot line of the relief valve reaches 450 psi (3 bar), the valve will open, dumping operating pressure oil through port T of the lift valve to the hydraulic tank Rev B

21 Lower Circuit Schematic See Figure -9. Lift/Lower Test Port G Lift P Solenoid 2 3 T T Lower Relief 450 psi in in in in in in in. One-Way Restrictor in in. Left Front Cylinder Center Cylinder Left Rear Cylinder Right Rear Cylinder Right Front Cylinder in. Operating Pressure Oil Metered Oil Return Oil Operating Pressure Oil from Steering Unit (Port E) 3 Return Oil to Hydraulic Tank 2 Return Oil from Steering Unit (Port T) Figure -9 TN Rev B -2

22 Mow Circuit (On) Schematic and Theory of Operation System Conditions: Engine running Cutting units lowered Mow switch in the on position Backlap switch in the off position Park brake switch in the off position (park brake disengaged) S See Mow Circuit Theory of Operation on page 4-25 for the electrical operation of this circuit. The function of each reel valve is the same, except where noted. Oil Supply to Reel s Oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Sections 2 (rear reel) and 3 (front reel) supply operating pressure oil to port P of the corresponding reel valves. Mow Circuit Operating pressure oil supplied by sections 2 and 3 of the gear pump enters the reel valve bodies at port P and is routed to the solenoid valves. With the mow switch in the on position, the valves shift, routing operating pressure oil through port A to the reel motors. Operating pressure oil flows against the check valve and 7 psi (80 bar) forward relief valves, driving the motors. Circuit Relief The mow circuit is protected by the 7 psi (80 bar) pilot-operated forward relief valves. The relief valves for the front and center reel motors will open if the oil pressure in the circuit reaches 7 psi (80 bar), routing oil through the bypass to the next motor in series, then through the front reel valve to the return filter, oil cooler, and then the hydraulic tank. The relief valves for the rear reel motors will open if the oil pressure in the circuit reaches 7 psi (80 bar), routing oil through the bypass to the next motor in series, then through the rear reel valve to the charge filter. Oil Return Oil returning from the motors enters the reel valve at port B and flows through the solenoid valve, exiting the valve at port T. Front Reels: The oil from these motors is routed to the return filter to remove debris from the oil. If the oil pressure at the 0-micron filter reaches 25 psi (.7 bar), the 25 psi (.7 bar) crack bypass will open, allowing oil to bypass the 0-micron filter. Oil from the return filter is routed through the oil cooler to the hydraulic tank. If the oil pressure at the oil cooler reaches 25 psi (.7 bar), the 25 psi (.7 bar) crack bypass will open, allowing oil to bypass the oil cooler and return to the hydraulic tank. Rear Reels: The oil from these motors is routed to the charge filter to remove debris from the oil. If the charge filter becomes plugged, a 25 psi (.7 bar) pressure switch will activate the Hydraulic Oil Filter light on the LDU and the charge filter will be bypassed. Oil from the charge filter is routed to the traction pump to fill the closed-loop traction circuit. Once filled, the 35 psi (22 bar) charge pressure relief valve will open, allowing oil to return to the hydraulic tank. Hydraulic oil is used to lubricate the internal components of the reel motors. This oil is returned via the case drain lines back to the hydraulic tank Rev B

23 Mow Circuit (On) Schematic See Figure -0. RF Reel Motor C Reel Motor LF Reel Motor Reverse Relief 7 psi Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi Forward Relief 7 psi RR Reel Motor LR Reel Motor Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi A B A B Solenoid Backlap Solenoid Backlap Rear Reel Test Port G Rear Reel Front Reel Test Port G Front Reel P T P T Operating Pressure Oil Charge Pressure Oil Inlet or Drain Oil Return Oil Reel Motors Case Drain Oil to Hydraulic Tank 4 Charge Pressure Oil to Charge Filter 2 Return Oil to Return Filter and Oil Cooler 5 Operating Pressure Oil from Gear Pump (Section 3) 3 Operating Pressure Oil from Gear Pump (Section 2) Figure -0 TN Rev B -23

24 Backlap Circuit Schematic and Theory of Operation System Conditions: Engine running Cutting units lowered Traction pedal in the neutral position Backlap switch in the on position Park brake switch in the on position (park brake engaged) S See Mow Circuit Theory of Operation on page 4-25 for the electrical operation of this circuit. The function of each reel valve is the same, except where noted. Oil Supply to Reel s Oil is drawn from the hydraulic tank through a 00-mesh screen, and enters the gear pump, supplying oil to all three pump sections. Sections 2 (rear reel) and 3 (front reel) supply operating pressure oil to port P of the corresponding reel valves. Backlap Circuit Operating pressure oil supplied by sections 2 and 3 of the gear pump enters the reel valve bodies at port P and is routed to the solenoid valves. When the backlap switch is in the on position, the solenoid valves shift. This routes operating pressure oil out port B to the reel motors in series, driving the reel motors in the reverse direction. The oil flow to the reel motors is adjustable, with the backlap valve controlling the speed of the reels for the backlap process. The adjusted rate of oil flow will regulate reverse rotational speed and maintain reverse motor speed as load is applied to the reel motors. Speed adjustment settings can be maintained and will not affect mowing operation when motors are shifted to mow rotation. Circuit Relief The backlap circuit is protected by the 7 psi (80 bar) pilot-operated reverse relief valves. The relief valves for the front and center reel motors will open if the oil pressure in the circuit reaches 7 psi (80 bar), routing oil through the bypass to the next motor in series, then through the front reel valve to the return filter, oil cooler, and then the hydraulic tank. The relief valves for the rear reel motors will open if the oil pressure in the circuit reaches 7 psi (80 bar), routing oil through the bypass to the next motor in series, then through the rear reel valve to the charge filter. Oil Return Oil returning from the motors enters the reel valve at port A and flows through the solenoid valve, exiting the valve at port T. Oil flow through the backlap valve is also routed to port P of the reel valve. Front Reels: The oil from these motors is routed to the return filter to remove debris from the oil. If the oil pressure at the 0-micron filter reaches 25 psi (.7 bar), the 25 psi (.7 bar) crack bypass will open, allowing oil to bypass the 0-micron filter. Oil from the return filter is routed through the oil cooler to the hydraulic tank. If the oil pressure at the oil cooler reaches 25 psi (.7 bar), the 25 psi (.7 bar) crack bypass will open, allowing oil to bypass the oil cooler and return to the hydraulic tank. Rear Reels: The oil from these motors is routed to the charge filter to remove debris from the oil. If the charge filter becomes plugged, a 25 psi (.7 bar) pressure switch will activate the Hydraulic Oil Filter light on the LDU and the charge filter will be bypassed. Oil from the charge filter is routed to the 35 psi (22 bar) pilot-operated relief valve. When the oil pressure reaches 35 psi (22 bar), the valve will open, allowing oil to return to the hydraulic tank. Hydraulic oil is used to lubricate the internal components of the reel motors. This oil is returned via the case drain lines back to the hydraulic tank Rev B

25 Backlap Circuit Schematic See Figure -. RF Reel Motor C Reel Motor LF Reel Motor Reverse Relief 7 psi Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi Forward Relief 7 psi RR Reel Motor LR Reel Motor Reverse Relief 7 psi Reverse Relief 7 psi Reel Motor Displacement LF ci LF ci Forward Relief 7 psi Forward Relief 7 psi A B A B Solenoid Backlap Solenoid Backlap Rear Reel Test Port G Rear Reel Front Reel Test Port G Front Reel P T P T Operating Pressure Oil Metered Oil Inlet or Drain Oil Return Oil Reel Motors Case Drain Oil to Hydraulic Tank 4 Charge Pressure Oil to Charge Filter 2 Return Oil to Return Filter and Oil Cooler 5 Operating Pressure Oil from Gear Pump (Section 3) 3 Operating Pressure Oil from Gear Pump (Section 2) Figure - TN Rev B -25

26 Field Test Procedures When a hydraulic system failure occurs, some simple effective tests can be performed prior to using a test instrument. The results of these tests can lead you to the suspected component failure. More extensive test procedures, using test instruments, are presented later in this section. (See Instrument Test Procedures on page -29.) 2 Preliminary s Perform the following checks prior to beginning any tests.. the hydraulic oil reservoir for proper fluid level, the presence of air or water, and unusual odor. 2. all hoses, tubes, and fittings for leaks. Tighten as needed. Eliminate all mechanical issues prior to starting hydraulic tests. Lift Cylinder Leakage Test See Figures -2 and -3. Front right lift cylinder is shown; procedure is similar for all lift cylinders.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury.. Start engine. Operate hydraulic system until oil temperature is at F (49 5 C). 2. Raise cutting units. 3. Park the mower safely. (See Park Mower Safely on page -.) 4. Support all cutting unit lift arms. Figure -2 TN Disconnect hose (2) from lift cylinder rod end fitting ().. Install plug in hose (2). 7. Install cap on lift cylinder fitting (). 8. Remove support from cutting unit lift arm being tested. After 5 minutes, does cutting unit drift down? YES Cylinder is bypassing oil. Repair or replace lift cylinder. (See Center Lift Cylinder on page -8 or Left and Right Front Lift Cylinders on page -7.) NO Repeat the test for all of the lift cylinders. If all cylinders pass test, the problem may be in the lift valve. Proceed to step Support all cutting unit lift arms. 0. Connect hose (2) to lift cylinder fitting ().. Start the engine and lower cutting units. 2. Stop the engine Rev B

27 Figure TN3744 Steering Leakage Test See Figure -4.. Operate hydraulic system until oil temperature is at F (49 5 C). 2. Turn steering wheel fully left against stop. 3. Park the mower safely. (See Park Mower Safely on page -.)! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. IMPORTANT Cutting units must be lowered to the ground. 3. Remove check valves (3) from the lift valve body (4). 4. Clean and inspect check valves for damage. Replace as necessary. 5. Start the engine and raise the cutting units.. Stop the engine. 7. If lift cylinders continue to drift down, start the engine and lower the cutting units. 8. Stop the engine. Figure Disconnect hose (2) from steering cylinder fitting (3). Plug hose. 5. Position a suitable container under steering cylinder fitting (3).! WARNING Do not turn steering wheel to the right. Failure to follow appropriate safety precautions may result in death or serious injury. 3 2 TN3747. With engine off, turn steering wheel fully left against stop. 7. for oil leakage in the drain pan. Is steering cylinder leakage a nominal amount of oil or less? YES Go to step 8. NO Repair or replace steering cylinder. (See Steering Cylinder on page 7-2.) Rev B -27

28 8. Disconnect and plug hose (). 9. Start the engine and set engine speed to full throttle (350 ± 50 rpm). 0. Turn the steering wheel fully left, then fully right. Does the steering wheel continue to turn past stop with little or no resistance? YES Steering unit is faulty; replace steering unit. (See Steering Unit on page 7-9.) NO Steering unit is good. Test complete. Reel Motor Case Drain Test The cutting units system consists of two circuits: the front cutting units circuit and the rear cutting units circuit. The front cutting units circuit consists of the front cutting units pump, front reel valve, right front reel motor, center reel motor, and left front reel motor. The rear cutting units circuit consists of the rear cutting units pump, rear reel valve, right rear reel motor, and left rear reel motor. This test helps to determine if one of the reel motors is faulty. An instrument test must be performed to isolate the performance of the cutting units pumps and reel valves. S Perform test on only one reel motor at a time. The case drain on a hydraulic motor is used to return lubrication or bypassed hydraulic oil back to the hydraulic tank.. Operate the machine until hydraulic oil reaches operating temperature, F (49 5 C). 2. Stop the engine and remove the key. 3. Bypass the seat switch. 4. Remove the case drain hose from the reel motor. Immediately plug the hose. 5. Position a drain pan with a minimum capacity of gallon (3.8 L) near the reel motor.. Install a separate hose on the case drain fitting and place the free end in the container. Secure the hose to prevent spills.! WARNING Safely block cutting unit from rotating using a suitable device or tool. Failure to follow appropriate safety precautions may result in death or serious injury. 9. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels for 5 seconds. 0. Disengage the mow switch, stop the engine, and remove the ignition key.. Measure the amount of oil that flowed from the case drain. The amount x 4 = amount per minute. Is the oil captured from the case drain within a half pint per minute? YES The motor shaft and/or bearings are not faulty; proceed with an instrument test. (See Instrument Test Procedures on page -29.) Is the oil captured from the case drain more than pint per minute? YES The motor may be faulty; repair or replace as needed. (See Reel Drive Motor 5-Inch Cutting Unit on page 8-25 or Reel Drive Motor 7-Inch Cutting Unit on page 8-28.) 2. Disconnect and remove test equipment. Install all hoses, fittings, and components as noted prior to removal. 7. Install suitable blocking device or tool in cutting unit being tested, preventing cutting unit from turning. 8. Engage the park brake (park brake switch in the on position) and start the engine Rev B

29 Instrument Test Procedures Instrument Test Overview The following tests are specifically designed to approach hydraulic testing on a system level. Each component within the system represents a portion of the total system leakage. An internal leakage percentage for each component will be calculated and recorded, enabling the technician to view the system performance issue more completely. The test results will help the technician to determine which repairs will best remedy the performance issue experienced by the machine operator. The internal leakage percentage ranges are as follows: 0 0% = Good 20% = Marginal 2% and Beyond = Bad Example: Cutting Unit System Performance Complaint The machine operator reports the mower is not cutting correctly. Troubleshooting must first be performed to rule out a cutting unit adjustment issue. Once the issue is known to be component related, the entire cutting unit system is tested as outlined. The calculated system leakage is 28%, a result that requires the testing of individual components. This result can also be interpreted as the system is 72% efficient. The remaining components in question are as follows: front cutting units pump, front reel valve, right front reel motor, center reel motor, and left front reel motor. Following the procedures as outlined, test each individual component, then calculate and record leakage percentages. The results from this test reveal leakage of 5% in the front cutting units pump, 5.3% in the front reel valve, 20% in the right front reel motor, 5.% in the center reel motor, and 4.4% in the left front reel motor. Although all the components lend to the overall circuit leakage, only the right front reel motor, which is at the extreme end of the marginal range, would be considered for repair/replacement. Formulas: Front Cutting Units Circuit Test No Load Flow Loaded Flow / No Load Flow x 00 = Leak Percentage Reel Motor and Reel Loaded Flow from previous component Loaded Flow from current component / Loaded Flow from previous component x 00 = Leak Percentage Calculations: Front Cutting Units Circuit Test No Load Flow = 0 gpm Loaded Flow = 7.2 gpm / 0 x 00 = Total Circuit Leakage 28% Front Cutting Units Pump Test No Load Flow = 0 gpm Loaded Flow = 9.5 gpm / 0 x 00 = Front Cutting Units Pump Leakage 5% Front Reel Test Loaded Flow from front cutting units pump test = 9.5 gpm Loaded Flow from front reel valve test = 9 gpm / 9.5 x 00 = Front Reel Leakage 5.3% Right Front Reel Motor Test Loaded Flow from front reel valve test = 9 gpm Loaded Flow from right front cutting unit motor test = 7.2 gpm / 9 x 00 = Right Front Cutting Unit Motor Leakage 20% Center Reel Motor Test Loaded Flow from left front cutting unit motor test = 7.2 gpm Loaded Flow from center cutting unit motor test =.8 gpm / 7.2 x 00 = Center Cutting Unit Motor Leakage 5.% Left Front Reel Motor Test Loaded Flow from center cutting unit motor test =.8 gpm Loaded Flow from left front cutting unit motor test =.5 gpm.8.5 /.8 x 00 = Left Front Cutting Unit Motor Leakage 4.4% Rev B -29

30 Front Cutting Units Circuit Test See Figures -5 through -7. IMPORTANT Performing this test will isolate the front cutting units pump, front reel valve, and right front reel motor from the rest of the front cutting units circuit. This test works together with the Front Cutting Units Circuit Test, Front Reel Test, and Front Reel Motors Test, to isolate a problem with the front cutting units circuit. 2! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Figure Disconnect hose () from fitting (2). TN34 Required Tools and Materials 3 Flow Meter -0 ORFS Test Hose 4000 psi (27 bar) -0 ORFS Tee Fitting Blocking Device or Tool. Park the mower safely. (See Park Mower Safely on page -.) 2. Remove hydro cover. (See Hydro Cover on page 9-4.). 3. Remove floorboard. (See Floorboard on page 9-4.) Figure - 5. Install tee fitting (5) to fitting (2).. Connect test hose () of flow meter inlet and hose () to tee fitting (5). Make sure hose end is under oil level in hydraulic tank to prevent aeration of oil. 7. Secure flow meter outlet hose (3) to the hydraulic tank fillneck. 5 4 TN Rev B

31 ! WARNING Safely block cutting unit from rotating using a suitable device or tool. Failure to follow appropriate safety precautions may result in death or serious injury. 8. Install suitable blocking device or tool in right front cutting unit, preventing the reel motor from turning. 9. Open flow meter valve (4) completely. 4. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels. 5. Read and record the front cutting units circuit no load flow.. Slowly close flow meter valve (4) until a pressure of 900 psi (2 bar) or 75% of the relief valve rating is reached. Read and record the front cutting units circuit loaded flow. 7. Open flow meter valve (4), disengage mow switch, and stop engine. 8. Calculate front cutting units circuit leakage. (Step 5 Step / Step 5 x 00 = Leak Percentage) Is front cutting units circuit leakage 0% or less? YES The front cutting units circuit is good. Proceed to Front Reel Motors Test on page -35. NO Proceed to next question. Is front cutting units circuit leakage % to 20%? YES The front cutting units circuit is marginal. Additional testing is required. Proceed to Front Cutting Units Pump Test on page -32. NO Proceed to next question. Is front cutting units circuit leakage 2% or more? YES Test individual components in front cutting units circuit for leakage. Proceed to Front Cutting Units Pump Test on page -32. Figure -7: Front Cutting Units Circuit Test Right Front Reel Motor Blocked 0. Block both sides of rear wheels using suitable wheel blocks.. Bypass seat switch. TN289 Verify engine rpm is within specification (350 rpm ± 50) to ensure accurate hydraulic test results. 2. Start engine and run at full throttle (350 rpm ± 50). 3. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve (4) until a reading of 500 psi (35 bar) or one half of the relief valve rating is reached. Warm oil to F (49 5 C); open valve fully after operating temperature is reached Rev B -3

32 Front Cutting Units Pump Test See Figures -8 through -20. IMPORTANT Performing this test will isolate the front cutting units pump from the rest of the front cutting units circuit. This test works together with the Front Cutting Units Circuit Test, Front Reel Test, and Front Reel Motors Test to isolate a problem with the front cutting units circuit.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Figure Install blocking disk between hydraulic hose () and tee fitting (3). 4. Open flow meter valve (2) completely. 3 2 TN33 Required Tools and Materials Flow Meter -0 ORFS Test Hose 4000 psi (27 bar) -0 ORFS Tee Fitting -0 ORFS Blocking Disk. Park the mower safely. (See Park Mower Safely on page -.) 2. Before performing this test, perform Front Cutting Units Circuit Test, leaving flow meter connected as outlined. TN2892 Figure -20: Front Cutting Units Pump Test Blocking Disk Between Pump and Front Reel 5. Block both sides of rear wheels using suitable wheel blocks.. Bypass seat switch. Figure -8 TN Rev B

33 Verify engine rpm is within specification (350 rpm ± 50) to ensure accurate hydraulic test results. 7. Start engine and run at full throttle (350 rpm ± 50).! CAUTION Do not exceed 7 psi (80.5 bar) as this test does not utilize system relief and damage may occur to hydraulic system components. 8. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve (2) until a reading of 500 psi (35 bar) or one half of the relief valve rating is reached. Warm oil to F (49 5 C); open valve fully after operating temperature is reached. 9. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels. 0. Slowly close flow meter valve (2) until a pressure of 900 psi (2 bar) or 75% of the relief valve rating is reached. Read and record the front cutting units pump loaded flow.. Open flow meter valve, disengage mow switch, and stop engine. 2. Calculate front cutting units pump leakage. (Step 5 of previous test Step 0 / Step 5 of previous test x 00 = Leak Percentage) Is front cutting units pump leakage 0% or less? YES The front cutting units pump is good. Proceed to step 3. NO Proceed to next question. Is front cutting units pump leakage % to 20%? YES The front cutting units pump is marginal. Additional testing is required. Proceed to step 3. NO Proceed to next question. Is front cutting units pump leakage 2% or more? YES Repair or replace front cutting units pump. See Gear Pump on page -52 then proceed to step 3. NO Proceed to step (See Figure -8.) Disconnect hydraulic hose () at tee fitting (3) and remove blocking disk. Reconnect hydraulic hose to tee fitting. 4. Proceed to Front Reel Test on page -33. Front Reel Test See Figures -2 through -23. IMPORTANT Performing this test will isolate the front reel valve from the rest of the front cutting units circuit. This test works together with the Front Cutting Units Circuit Test, Front Cutting Units Pump Test, and Front Reel Motors Test to isolate a problem with the front cutting units circuit.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Required Tools and Materials Flow Meter -0 ORFS Test Hose 4000 psi (27 bar) -0 ORFS Tee Fitting -0 ORFS Blocking Disk. Park the mower safely. (See Park Mower Safely on page -.) 2. Before performing this test, perform Front Cutting Units Circuit Test, leaving flow meter connected as outlined. Figure -2 TN Rev B -33

34 3. Install blocking disk at fitting () on right front reel motor, blocking oil flow from entering right front reel motor. Verify engine rpm is within specification (350 rpm ± 50) to ensure accurate hydraulic test results. 7. Start engine and run at full throttle (350 rpm ± 50).! CAUTION Do not exceed 7 psi (80.5 bar) as this test does not utilize system relief and damage may occur to hydraulic system components. Figure Open flow meter valve (2) completely. 2 TN33 8. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve (2) until a reading of 500 psi (35 bar) or one half of the relief valve rating is reached. Warm oil to F (49 5 C); open valve fully after operating temperature is reached. 9. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels. 0. Slowly close flow meter valve (2) until a pressure of 900 psi (2 bar) or 75% of the relief valve rating is reached. Read and record the front reel valve loaded flow.. Open flow meter valve, disengage mow switch, and stop engine. 2. Calculate front reel valve leakage. (Step 0 of previous test Step 0 / Step 0 of previous test x 00 = Leak Percentage) Is front reel valve leakage 0% or less? YES The front reel valve is good. Proceed to step 3. NO Proceed to next question. Is front reel valve leakage % to 20%? YES The front reel valve is marginal. Additional testing is required. Proceed to step 3. NO Proceed to next question. TN2893 Figure -23: Front Reel Test Blocking Disk at Right Front Reel Motor 5. Block both sides of rear wheels using suitable wheel blocks.. Bypass seat switch. Is front reel valve leakage 2% or more? YES Repair or replace reel valve. See Front Reel on page -3 then proceed to step (See Figure -2.) Disconnect hydraulic hose at fitting () on right front reel motor and remove blocking disk. 4. Reconnect hydraulic hose to right front reel motor. 5. Proceed to Front Reel Motors Test on page Rev B

35 Front Reel Motors Test See Figures -24 through -27. IMPORTANT Performing this test will isolate the front reel motors from the rest of the front cutting units circuit. This test works together with the Front Cutting Units Circuit Test, Front Cutting Units Pump Test, and Front Reel Test to isolate a problem with the front cutting units circuit.! WARNING The hydraulic system is under pressure, and the oil will be hot. Always relieve pressure in the hydraulic system before performing service. Failure to follow appropriate safety precautions may result in death or serious injury. Figure -24. Open flow meter valve () completely. TN33 Required Tools and Materials Flow Meter -0 ORFS Test Hose 4000 psi (27 bar) -0 ORFS Tee Fitting Blocking Device or Tool. Park the mower safely. (See Park Mower Safely on page -.) 2. Before performing this test, perform Front Reel Test, leaving flow meter connected as outlined. 3. Install suitable blocking device or tool in right front cutting unit, preventing the reel motor from turning. 4. Block both sides of rear wheels using suitable wheel blocks. 5. Bypass seat switch. TN289 Figure -25: Front Reel Motors Test Right Front Reel Motor Blocked Verify engine rpm is within specification (350 rpm ± 50) to ensure accurate hydraulic test results. 7. Start engine and run at full throttle (350 rpm ± 50) Rev B -35

36 8. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve () until a reading of 500 psi (35 bar) or one half of the relief valve rating is reached. Warm oil to F (49 5 C); open valve fully after operating temperature is reached. 9. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels. 0. Slowly close flow meter valve () until a pressure of 900 psi (2 bar) or 75% of the relief valve rating is reached. Read and record the right front reel motor loaded flow.. Open flow meter valve, disengage mow switch, and stop engine. 2. Calculate right front reel motor leakage. (Step 0 of front reel valve test Step 0 / Step 0 of front reel valve test x 00 = Leak Percentage) Is right front reel motor leakage 0% or less? YES The right front reel motor is good. Proceed to step 3. NO Proceed to next question. Is right front reel motor leakage % to 20%? YES The right front reel motor is marginal. Additional testing is required. Proceed to step 3. NO Proceed to next question. Is right front reel motor leakage 2% or more? YES Repair or replace right front reel motor. See Reel Drive Motor 5-Inch Cutting Unit on page 8-25 or Reel Drive Motor 7-Inch Cutting Unit on page 8-28 then proceed to step Remove blocking device or tool from right front reel motor.! WARNING Safely block cutting unit from rotating using a suitable device or tool. Failure to follow appropriate safety precautions may result in death or serious injury. 4. Install suitable blocking device or tool in center cutting unit, preventing center reel motor from turning. 5. Open flow meter valve completely. TN2894 Figure -2: Front Reel Motors Test Center Reel Motor Blocked Verify engine rpm is within specification (350 rpm ± 50) to ensure accurate hydraulic test results.. Start engine and run at full throttle (350 rpm ± 50). 7. Use the flow meter to warm the hydraulic oil. Turn the flow meter valve until a reading of 500 psi (35 bar) or one half of the relief valve rating is reached. Warm oil to F (49 5 C); open valve fully after operating temperature is reached. 8. Engage the mow switch, engage and release the raise/lower switch to the lower position twice, and operate the reels. 9. Slowly close flow meter valve until a pressure of 900 psi (2 bar) or 75% of the relief valve rating is reached. Read and record the center reel motor loaded flow. 20. Open flow meter valve, disengage mow switch, and stop engine Rev B