Fuel Tanks and Fuel Lines 47.00

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1 General Information General Information The fuel system consists of the engine fuel system components, the fuel tank(s) and tank mounting components, the fuel lines, and if so equipped, the shutoff valve(s). Vehicles with more than one fuel tank will have tee, or splitter valves to regulate fuel flow from and to the individual fuel tanks. The engine fuel system components typically include fuel filters, fuel injectors, fuel transfer pumps, and a fuel governor. For service and maintenance procedures, refer to the engine manufacturer s service and maintenance manuals. Metal straps hold the fuel tanks in place on J-brackets bolted to the vehicle frame. A cab access step assembly or a tank fairing may be attached to the fuel tank straps. Compression braces are mandatory on 5-inch and 6-inch tanks, optional on -inch and -inch tanks. Tanks 00 gallons or smaller require one compression brace, tanks larger than 00 gallons require two. Either wire braid or nylon flexible fuel lines carry fuel from the tank to the engine, and return unused fuel from the engine to the tank. Many procedures, short of installing a different fuel tank, can be performed without disconnecting the fuel lines, so that it is not necessary to prime the fuel system. A fuel level sensor (in the primary tank of a dual-tank system) feeds an electronic fuel level gauge in the cab instrument cluster. NOTE: In order for the system to keep fuel levels roughly equal in all tanks, the fuel lines must be properly routed. EquiFlo Fuel System (Used Since November, 004) Since November, 004, the EquiFlo dual suction/ dual return fuel system is standard on all vehicles with dual tanks. This system maintains similar fuel levels in both fuel tanks, without the need of a low crossover line. Vehicles fitted with the EquiFlo system use tee fittings in place of the splitter that was used before November, 004. See Fig. for the EquiFlo tee fittings system (used since November, 004) and see Fig. for the splitter system fittings (used until November, 004). 0//005 f Fuel Draw Tee. Fuel Return Tee Fig., Typical of EquiFlo Fuel System Tee (Used Since November, 004) The EquiFlo fuel draw system consists of an equal diameter, close to equal length, line from each tank, joining at a tee valve on the cab crossmember, or on the transmission.the fuel draw lines are routed similarly, to minimize flow differences between the sides. The flow from both lines combines at the tee valve, and from the tee valve, a single line supplies fuel to the engine. The line from the tee valve to the engine can be any size that fits the engine manufacturer s guidelines. Line Routing Fuel tank draw lines are installed so that they are level, or so that they rise steadily from the fuel tank to the tee valve. Upward bows in the lines can trap an air bubble, and downward bows in the lines can trap water. If the fuel lines are free of bubbles, they siphon fuel between the tanks, the same as a crossover line. However, an air bubble in the fuel line can break the siphon and prevent fuel level equalization. Fuel Tank Level Equalization If fuel levels in the tanks are equal and the lines are full, the engine will draw equally from each tank. If fuel levels are unequal, the engine will draw more from the full tank, equalizing the levels. If the tanks are different sizes, the larger tank will hold a slightly higher fuel level, causing more fuel to flow from it to the engine. On a long run, a vehicle with different size dual fuel tanks may develop a small difference in fuel levels Western Star Workshop Manual, Supplement 6, January /

2 47.00 General Information Fuel Tanks and Fuel Lines between the tanks. This situation will correct itself when the vehicle is parked, and the fuel siphons to the tank with the lower fuel level. Splitter System (Used Before November, 004) A single fuel line returns unused fuel from the engine to the return flow splitter valve, mounted on the front cab crossmember. See Fig.. The splitter system uses flow splitters for fuel level equalization. However, if the draw lines are not siphoning properly, draw flow may decrease or stop from a given fuel tank. Unused fuel from the fuel injection system returns to the return flow splitter valve. From the return flow splitter valve, separate lines carry fuel to the individual tanks. The return flow splitter valve proportions flow to each fuel line by maintaining constant back pressure, so that each fuel tank receives equal amounts of fuel. This keeps the fuel load balanced, and hot fuel evenly distributed, whether the vehicle is sitting flat, or on a slope. Return lines from the fuel return splitter to the tanks should be the same diameter, and of similar length. The return flow splitter compensates for moderate differences in routing, but not for large differences in routing and big loops in return lines. 0//00. Front Cab Crossmember. Fuel Return Splitter Valve. Fuel Draw Splitter Valve f47048 Fig., Fuel Splitter Mounted on the Front Cab Crossmember: Vehicles Built Before November, / Western Star Workshop Manual, Supplement 6, January 005

3 Fuel Tank Replacement Tank Replacement A Damaged fuel tanks must be replaced. A repaired fuel tank may not meet U.S. Federal strength, leakage, and venting standards required for all fuel tanks. A repaired fuel tank may be more likely to spill fuel or be ruptured in a vehicle accident, which could lead to personal injury or property damage. Do not drain fuel near, or allow fuel vapor near, open flame or intense heat. Doing so is a dangerous practice, and creates a severe fire hazard. This could lead to personal injury, or property damage.. Park the vehicle on level ground. Apply the parking brake and chock the tires. NOTE: All fuel tanks to be removed must be drained first. On multiple tank installations, if equipped with fuel tap(s), close the taps to prevent siphoning from other tanks to the one you are draining. Drain the existing tank completely.. Drain the fuel into a suitable container. Protect it from contamination. IMPORTANT: Be certain your container is suitable for holding diesel fuel, clean, and large enough to hold all of the fuel that is in the tank.. If a light bar is fitted over the fuel tank, disconnect its wiring harness, and remove the light bar. 4. Disconnect the fuel suction and return lines from the tank, and cap them. 5. Disconnect the fuel tank vent line. 6. Remove the fuel level sending unit. 7. Remove and clean all of the pipe plugs, and save them for installation on the new tank. 8. If a new same-size fuel tank is to be installed, measure and record the distance from the end of the fuel tank to the fuel tank band, and from the fuel filler cap to the end of the J-bracket. These measurements assist in installing the new tank in the correct position. See Fig.. 4 B 5 0/6/005 f A. Measure and record to position new tank. B. Measure and record to position new tank.. Fuel Tank Band. Fuel Tank Band Isolator. Fuel Tank Fig., Fuel Tank Orientation NOTE: A transmission jack, padded to prevent marking the tank finish, is a good tool to remove a fuel tank. A fork lift is also suitable. If a fork lift is used, fasten x 4 or 4 x 4 wooden blocks, spaced to hold the fuel tank and keep it from rolling, to the top of a pallet. Place the pallet on the forks of the fork lift. See Fig... Remove the four nuts and washers on the outside bottoms of the fuel tank bands. 0. Remove the bolts, nuts, and washers that hold the top of the fuel tank band.. Remove the tank bands with their rubber insulators.. Remove the fuel tank from the fuel tank bracket. NOTE: The tank may be stuck to the rubber insulator on the J-bracket, but it will come loose. Lift carefully, and take care to keep it evenly balanced.. After removing the tank, inspect the tank bands, insulators, and brackets for damage. Refer to Subject 0 for bracket replacement procedures. Failure to replace worn or damaged parts could result in loss of a fuel tank and spilling of fuel, which could cause property damage or personal injury. Western Star Workshop Manual, Supplement 6, January /

4 47.00 Fuel Tank Replacement Fuel Tanks and Fuel Lines 0/6/ " (46 cm) f NOTE: Fuel filler neck is positioned 5±5 degrees outboard of vertical.. J-Bracket Mount. Upper Fuel Tank Band Bolts. Steps 4. Fuel Tank 5. Lower Fuel Tank Band Hexnuts and Washers 6. Compression Brace Mounting Hole 7. J-Bracket 8. Fork Lift. Wood Blocks to Prevent Fuel Tank Rolling 0. Wood Pallet Insert the lower tank band studs in the J-brackets, and loosely install the washers and hexnuts. 8. Install the top tank band capscrews, washers, spacers, and nuts. Torque 0 to 5 lbf ft (4 to 47 N m). IMPORTANT: Tighten the band lower fasteners alternately in stages, to final torque of 8 lbf ft (4 N m). Overtightening the fuel tank bands can damage them, or the fuel tank.. Make certain the fuel lines are clean, then install them on their fuel tank fittings. 0. Install the fuel level sender, if equipped.. Coat the pipe plug threads with Loctite 5, or an equivalent high-temperature thread sealant. Install pipe plugs in any remaining open threaded holes.. Install the light bar, if equipped.. Fill the fuel tank with clean fuel. Prime the engine fuel pump; for instructions, refer to the engine manufacturer s operation and maintenance manual. 4. Open the fuel tap(s), if so equipped. Fig., Fuel Tank Assembly and Forklift Antiroll Pallet Assembly 4. If the fittings from the old tank are undamaged, install them on the new tank. If any part is damaged, install a new one. 5. Place the fuel tank in its approximate installed position on the J-brackets. Position the filler neck 5±5 degrees outboard from vertical. See Fig.. NOTE: On vehicles equipped with side fairings, the fuel tank filler neck need not be exactly centered in the fill door opening. The centerline of the fuel filler cap can be anywhere within one inch (5 mm) of the centerline of the fill door opening. 6. Place the tank bands, with their isolators, on the fuel tank. 00/ Western Star Workshop Manual, Supplement 6, January 005

5 Fuel Line Replacement Fuel Line Replacement Never bundle fuel lines with air conditioning lines. Never route fuel lines with electrical wiring, including electrical harnesses, battery cables, or jumper cables. Doing so creates a fire hazard, and may result in property damage or personal injury. If diesel fuel lines are worn, damaged, or deteriorated, replace them. Use the following guidelines for installing and routing them. Fuel lines must be free of droops, sharp bends, and kinks in the lines. Fuel lines must not extend below the fuel tank, unless they are completely enclosed in a protective housing. Fuel lines must be routed in a continuous upward slope from the fuel tanks, to prevent high and low spots in the hoses. Wire braid fuel line requires a 4-inch (00 mm) minimum clearance from exhaust pipes, but does not require additional heat insulation. Nylon fuel lines routed within 5 inches (5 mm) of exhaust system pipes must be protected with an approved exhaust shield or foam insulation. Fuel lines must be routed to allow routinely serviceable components, such as dipsticks, filters, and water separators, to be easily reached without the need to disconnect the fuel lines. Fuel lines must be secured to prevent chafing, kinking, or other damage. All fuel lines routed along the inside of the frame rail should be fastened with rubber bound clamps and standoffs, and clipped separately from the battery cables at all times, to avoid fire hazards. Space between clamps, whether inside or outside the frame rails, should be 6 inches (50 mm), maximum. Ties should be used between clamps, at a maximum distance of inches (05 mm) apart. Fuel lines should have a minimum of / inch ( mm) clearance from stationary parts. Fuel lines should have a minimum of inch (5 mm) clearance from any moving parts, and should be well secured near moving parts. Fuel lines must be long enough to follow full movement of the parts to which they are attached. Coat all tapered pipe threads with Loctite 5, or an equivalent high-temperature thread sealant. Finger-tighten pipe fittings; then tighten -/ turns. Tighten more, if necessary to seal. Fuel lines and fittings must be free of leaks. Fuel loss or entry of air into the fuel line can cause loss of prime in the engine fuel system. Drains or other bottom fittings must not extend more than /4 inch ( mm) below the lowest part of the fuel tank or sump. Western Star Workshop Manual, Supplement 6, January 005 0/

6 Fuel Tank Bracket and Band Replacement Fuel Tank Bracket and Band Replacement Damaged fuel tanks must be replaced. A repaired fuel tank may not meet U.S. Federal strength, leakage, and venting standards required for all fuel tanks. A repaired fuel tank may be more likely to spill fuel or be ruptured in a vehicle accident, which could lead to personal injury or property damage. Do not drain fuel near, or allow fuel vapor near, open flame or intense heat. Doing so is a dangerous practice, and creates a severe fire hazard. This could lead to personal injury, or property damage.. Park the vehicle on level ground. Apply the parking brake and chock the tires. NOTE: All fuel tanks to be removed must be drained first. On multiple tank installations, if equipped with fuel tap(s), close the taps to prevent siphoning from other tanks to the one you are draining. If the same tank will be installed, leave about 4 inches (00 mm) of fuel in the tank when it is drained, so that the fuel system does not need to be primed following the procedure. If a different tank is to be installed, drain the existing tank completely.. Drain the fuel into a suitable container. Protect it from contamination. IMPORTANT: Be certain your container is suitable for holding diesel fuel, clean, and large enough to hold all of the fuel that is in the tank.. If a light bar is fitted over the fuel tank, disconnect its wiring harness, and remove the light bar. 4. Drain the fuel tank that is to be worked on. NOTE: If the same tank will be installed, leave about 4 inches (00 mm) of fuel in it when it is drained, so that the fuel system does not need to be primed following the procedure. If a different tank is to be installed, drain the existing tank completely. 5. Support the tank with a transmission jack, a pallet on a fork lift, or other suitable, stable platform, and remove the fuel tank bands from the tank where the bracket is being replaced; see Fig.. 0/6/ " (46 cm) 5 5 CAUTION f If 4 inches (00 mm) of fuel are left in the tank so that the fuel system does not lose its prime, be very careful that fuel sloshing does not tip the tank as it moves, and be careful not to stretch or damage the fuel lines. 0. Frame Rail. Upper Tank Band Fasteners (Two Per Band). Step 4. Fuel Tank Interior 5. Lower Tank Band Fasteners (Two Per Band) 6. Compression Brace Fastener Hole 7. Fuel Tank J-Bracket 8. Fork Lift. Wood Blocks Fastened to Pallet 0. Wood Pallet on Fork Lift Fork Fig., Fuel Tank Assembly and Forklift Antiroll Pallet Assembly Western Star Workshop Manual, Supplement 6, January 005 0/

7 47.00 Fuel Tank Bracket and Band Replacement Fuel Tanks and Fuel Lines NOTE: If the fuel tank is to be replaced, place suitable containers in position to catch any remaining fuel as the fuel lines are removed. 6. If the fuel tank is to be replaced, disconnect the fuel lines and fuel tank vent hose. If the fuel tank is not to be replaced, leave the fuel lines connected, so that the fuel system does not have to be primed. NOTE: It is not necessary to disconnect the fuel lines and vent hose to change only the J-bracket or its fittings. The fuel lines should allow sufficient careful movement of the tank to replace the brackets, though some fuel line tiewraps or P-clamps may need to be removed to allow tank movement without damaging the fuel lines. 7. Move the fuel tank enough to gain access to the bracket. 4. Install the fuel tank bands; refer to Subject If a fuel level sender was removed, install it. 6. If the fuel lines and vent hose were disconnected, connect them. Fill the tanks with clean fuel. 7. If fuel taps were closed, open them. 8. Prime the fuel system CAUTION Be very careful not to stretch or otherwise damage the fuel lines, if the fuel tank is moved without disconnecting them. Also, be careful that the 4-inches (00 mm) of fuel left in the tank, to keep the lines primed, does not slosh around and cause the tank to tip. 8. Remove the fasteners from the compression brace(s), if so equipped.. Remove the fasteners that attach the bracket to the frame rail, then remove the bracket. Keep the fasteners in order, so they can be installed in the same holes. 0. Position the new tank bracket against the frame rail.. Loosely install all of the bolts including those on the compression braces, with the hardened washers and hexnuts.. Tighten the hexnuts 60 lbf ft (7 N m).. Install the fuel tank. IMPORTANT: Face to face tank spacing clearance must be at least inch (5 mm); inches (75 mm) spacing is preferred. Clearance between the fuel tank face and the hood or fenders must be at least inches (50 mm). 0/ Western Star Workshop Manual, Supplement 6, January 005

8 Fuel Shutoff Valve Replacement, EPA0 Engines Replacement. Apply the parking brakes, chock the tires, put the transmission into high gear, and open the hood. Aftertreatment device (ATD) internal temperatures can remain hot enough to cause personal injury or ignite combustible materials for hours after the engine is shut down, causing potentially serious burns or material damage. Wear appropriate protective gear when working around the ATD. Do not to let diesel from the fuel lines come into contact with the ATD.. Disconnect the driveline from the transmission output yoke. For instructions, see Section 4.00, Subject 00 for uncoupling from a half-round end-yoke, or Section 4.00, Subject 0 for uncoupling from a full-round endyoke.. Disconnect the driveline midship bearing from the midship bearing bracket, and set the driveline out of the way. 4. In order to gain access to the fuel shutoff valves, it may be necessary to remove the standoff brackets that secure the diesel exhaust fluid (DEF) lines to the EquiFlo bracket, then move the lines aside. See Fig.. 5. Disconnect the aftertreatment device (ATD) wiring harnesses located on the EquiFlo bracket. In order to gain access to the fuel shutoff valves, it may be necessary to remove the standoff brackets that secure the wiring harnesses to the EquiFlo bracket, then move the harnesses aside. 6. Disconnect the fuel lines from the tee fittings, then cap the lines. 7. Remove any remaining cables and brackets as needed to access the fuel shutoff valves. 8. Loosen the two jam nuts that secure the fuel shutoff valves and tee fittings to the EquiFlo bracket. Remove the tee fittings and valves as an assembly.. Remove the shutoff valves from the tee fittings, then install new shutoff valves. 0. Using two jam nuts, install the tee fitting and shutoff valve assembly on the EquiFlo bracket.. Install the fuel lines on the tee fittings and tighten the fittings.. If any ATD wiring harness standoff brackets were previously removed, install them on the EquiFlo bracket, then connect the wiring harnesses.. If any DEF line standoff brackets were previously removed, install them on the EquiFlo bracket. 4. Install any remaining cables and brackets that were previously removed. 5. Connect the driveline to the transmission output yoke. For instructions, see Section 4.00, Subject 00 for coupling to a half-round end-yoke, or Section 4.00, Subject 0 for coupling to a full-round end-yoke. 6. Connect the midship bearing to the midship bearing bracket. 7. Start the engine and check for leaks. Western Star Workshop Manual, Supplement 6, May 0 0/

9 47.00 Fuel Shutoff Valve Replacement, EPA0 Engines Fuel Tanks and Fuel Lines //00 f Fuel Supply Line to Engine. Fuel Return Line from Engine. Fuel Shutoff Valves (qty ) 4. Fuel Return Line to Right-Hand Fuel Tank 5. Fuel Supply Line from Right- Hand Tank 6. EquiFlo Bracket 7. ATD Wiring Harnesses 8. Coolant Lines (to and from DEF tank). Fuel Supply Line from Left-Hand Tank Fig., Fuel Shutoff Valve Assembly, Dual-Tank Vehicle 0. Fuel Return Line to Left-Hand Tank. EquiFlo Bracket Stud (qty ). Washer (qty ). Jam Nut (qty ) 0/ Western Star Workshop Manual, Supplement 6, May 0