BMW E38 730i Rear Ball Joint & Strut Replacement

Transcription

1 BMW E38 730i Rear Ball Joint & Strut Replacement This technique was developed by a non-mechanic working on a i. Notes: If your car is as old as mine and done 100,000+ miles without having the strut or ball joints replaced then I recommend they are changed. When working with a car of this age expect problems with rust/oxidation on parts, you will more than likely need a large breaker bar to free up a lot of bolts. I actually broke a ratchet trying to remove a big nut. You ve been warned! If the struts have been in for 100,000+ miles they will be very hard to remove in the recommended way. The eyelet that attaches them to the wheel carrier rusts up and the whole thing jams and won t budge easily. I recommend allocating at least a weekend s worth of time to do this job. Ball joints I would recommend that you get OEM parts as I bought equivalento ones as the packet said and they didn t fit the special tool I had bought correctly. For reference the BMW part no is A BMW dealer sells them for about 35 each, Euro Car Parts do Lemforder OEMs for about 22 (I used these). It is part number 2 found here: Aftermarket springs Before I started this job I bought my coil springs from 2 different suppliers, BOGE and KME-Lesjofors (these are either branded as K.M.E. or Lesjofors. Incredibly there were a great number of differences between the two. The KME-Lesjofors spring was approximately 10-15mm longer than the BOGE one, this meant the distance between the loops of the spring were different. The BOGE spring was smaller in diameter by about 3mm The BOGE spring sat better on the rubber pads. The start and end points of both springs were different The BOGE spring was much easier to compress for fitting onto the strut I recommend you buy the BOGE springs, they are available from ECP but you should specifically ask for them as they have 4 different suppliers for the same part. The BOGE part number is: 25-C54-0 for my car at least. Refer to this website for up-to-date part information: Tools: - Jack + axle stands - Ball joint removal tool (I used the Sykes Pickavant one from ebay, it cost about 80) DON T attempt this procedure without this tool unless you have the resources to make your own. I tried to fashion one with various bits from a hardware store, it was NOT successful. The tool makes life so much easier. -Felt tip marker + ruler - Ratchet set (2 ratchets ideally) Long + short extender bar 10mm, 13mm, 15mm, 17mm, 18mm, 22mm, 24mm sockets. 22mm deep socket Breaker bar

2 - Spanners 10mm, 17mm, 24mm - Mole grip - Spring compressors - Assorted screwdrivers - Pry bars (a long one + very short one ideally) - Grease - Blowlamp (I used a bog standard one for doing indoor plumbing) - Torque wrench I didn t use one but you may want to - Dead blow hammer Procedure: 1. Unfortunately to get access to the upper strut mountings you have to remove the rear interior of the car. It s a bit of pain but it should only take 20 minutes. Make sure you use clean tools so as not to mess up your interior. It s also a good opportunity to have a good vacuum under the seats and find the odd pound coin that s slipped behind them. A good write up of rear seat removal can be found here: I would strongly recommend noting down where all the nuts go as this will make it much easier to put everything back. With the rear seats removed it s now time to set to work on the ball joint and struts. 2. I used the jack supplied with car and put an axle stand under the rear lift pad mount. Remove the wheel and place it under the car for added safety. (I had my car on an axle stand for 6 weeks without problems better to be safe than sorry though) Take your time to get acquainted with everything, take pictures if necessary. 3. Use a felt tip pen to mark the eccentric bolt and swing arm so that the car will be mostly aligned when you reassemble things. I used a ruler and drew a line across the eccentric bolt and swing as follows: (You may want to take a picture for future reference) 4. Unbolt the brake caliper from the wheel carrier and place it on some bricks or a bucket so as not to strain the brake hose.

3 5. Using a 24mm socket and a large breaker bar, remove the nut from the end of the eccentric bolt. You will need to use another ratchet/spanner to hold the eccentric bolt to prevent it from turning once the nut is loose. The bolt needs an 18mm socket but I don t have one so I was able to get away with a 19mm. 6. With the nut removed, gently tap the bolt towards the front of the car until you can grab it with your hand on the other side. Pull the eccentric bolt almost the entire way out apart from about 2 inches. You want the bolt to be clear of the integral link for ease of removal. 7. Next remove the upper bolt holding the integral link in. 8. With the bolt removed you should now be able to pull the integral link out. It ll take a bit of wangling and maybe the odd tap with a hammer but it should come free. 9. Now pull the eccentric bolt out completely. When the threaded end of the bolt enters the ball joint you will need to turn the bolt to get it to come out. I used a pair of mole grips so I could pull and twist at the same time. It s not actually threaded it s just the load of the sprung swing arm causing problems. You ve almost got access to the ball joint, just one more step. 10. Using a 22mm deep socket remove the bolt holding the wishbone in (pictured below). After it s initially loosened you may have to use a 10mm and 22mm spanners to counteract the spinning spindle in the wishbone. Pull the wishbone free of the wheel carrier and support as necessary.

4 Congratulations! You now have access to the ball joint. 11. Remove the circlip/snap ring that encircles the ball joint. In my case both were rusted/oxidised badly and were a pain to remove. It can take up to 20 minutes! I started by spraying a little bit of WD40 over the area to try and remove excess dirt etc. Get a small flat bladed screwdriver with as sharp a head as possible. Try to hammer the screwdriver under the circlip so you can get a mole grip on the end of it. With a mole grip you should be able to twist and contort the circlip so it pulls off. Keep at it. It will come off! 12. Now it s time to use the special tool. Assemble the tool as shown below. If the extractor shell won t fit over the ball joint properly use a file to remove old rust and dirt for it to fit properly. Grease the main drive stud and thrust bearing assembly before starting. Hand tighten the nuts at either end to take up any slack. You will need to use a 24mm socket on B1 (to counteract any spinning) and 24mm spanner on A1. Slowly turn A1 with your ring spanner until everything feels tight, keep going until a loud clink sound. The stiction on the ball joint has been broken. Keep turning the spanner until the ball joint is out and everything feels loose. Remove the special tool and you ll be left with this: Clean out the ring of any dirt 13. I recommend doing the strut replacement next as there will be more room to manoeuvre. Start by removing the 3 nuts that hold the top of the strut in place. They are located inside the car under the parcel shelf before removal. You will need to cut/rip a protective layer of foam away to gain access.

5 3 x 13mm nuts 14. Remove the bolt at the bottom of the shock absorber that holds it in place with the wheel carrier. 22mm socket required 15. In a perfect world you should just be able to knock the old strut out with a hammer. If your car has done high mileage without the struts being removed it is very unlikely that they will budge with just a hammer. Try applying heat to the area with a blow lamp/gas torch and hammering at the same time. This was unsuccessful for me so I had to develop my own method. If you were successful then skip to step 22. WARNING: HAVE A FIRE EXTINGUISHER ON STANDBY AT ALL TIMES! 16. This method will ruin the old shocks so make sure you have new ones (I used Bilstein B4 Gas BNE- 2687). Start by reattaching the three 13mm nuts you removed earlier, this will make the next step easier. 17. Using a suitable hacksaw, saw through the strut at the point where the metal ring around the eyelet meets the vertical piece of the strut (illustrated below using picture of new strut and spring). This will take a lot of time and patience. Try to only make one cut, if you make two they may not meet up in the middle. Try to cut level or you may cut too high resulting in fluid from the old struts leaking. If this happens surround the area with rags and just keep cutting, eventually it will all come out. It took me 30 minutes to an hour to saw through the strut. When are you close to cutting all the way through, a sharp tap with the hammer will free it.

6 18. Remove the three 13mm nuts again and remove the strut (well at least 90% of it anyway) and coil spring. 19. The next trick is to remove the ring of metal that encapsulates the eyelet, it is held in place by rubber essentially. Using a blow lamp/gas torch to melt/destroy the rubber and then tap the metal ring off with a hammer. You may require an assistant. There will be bits of melted rubber everywhere unfortunately. Do your best to clean everything. You will now be left with this: Strut eyelet stuck in wheel carrier 20. Firmly attach a pair of mole grips to the eyelet where it bulges in the middle. Get your gas lamp out again and heat the wheel carrier for about 5 minutes. When you think everything is hot enough, give the mole grips a sharp tap with a hammer. The eyelet should spin, twist the mole grips up and down to free the eyelet, it will come out with a bit of muscle and patience. It s hard work and unconventional but it s how I managed to get the strut out. 21. With the eyelet out, clean up the hole it came from with some WD-40 to remove rust. 22. Time now to return to the ball joint. Assemble the special tool as shown below: Make sure you put the ball joint in the correct way round! Turn the nut until the ball joint is pushed into position and the flange is firmly located against the wheel carrier housing.

7 23. Install a new circlip/snap ring. It should all look something like this: 24. Time to start putting things back. You will need an assistant to help while you line the suspension components up. The swing arm wants to travel up as it is spring loaded. Using two hands push it down by kneeling over the brake disk. Use enough force to bring the swing arm hole into line with ball joint hole. Be careful not to damage the rubber on the ball joint. Hold everything in position while your assistant pushes the bolt through the swing arm and ball joint. 25. Adjust the bolt so it doesn t poke out the other end of the ball joint, this is to help install the integral link. 26. Reinstall the integral link. Everything will be very tight so you may have to jiggle things or use the odd tap with a hammer. Make sure the upper hole of the integral link is properly lined up with the upper mounting point of the wheel carrier. Ensure that the bolt will thread properly and freely without cross threading (it may take a few goes to get the alignment correct). Reinstall the upper mounting bolt. 27. Push down on the swing arm again to bring the bottom hole of the integral link into the line with the swing arm. A small pry bar or screwdriver may help. 28. With the 2 holes lined up get your assistant to push the eccentric bolt the whole way through. A gentle tap with a hammer may help. 29. Turn the eccentric bolt to drive it home. Install the 24mm nut making sure the eccentric bolt does not turn. Use a spanner or socket to counteract any movement. Ensure everything is tight and that your alignment marks you made earlier are correct. 30. Onto the strut and coil spring. Assemble the new strut and coil spring using suitable compressors. Check the condition of the upper and lower rubber springs pads. Replace them if they are cracked or in unsuitable condition. Your newly assembled strut should look something like this: Ensure the spring is correctly located on the spring pads. You may find this diagram useful,

8 31. Reattach the strut with the nuts at the top. I recommend using 2 people for this as it can be difficult to line the 3 holes up. Use one person to hold the strut up while the other guides them and attaches the nuts once it is located. 32. With the strut hanging from its upper mounting point, reattach the wishbone. It takes a bit of muscle and a tap with a hammer. 33. Reinsert the bolt that holds the strut into the wheel carrier. It will be necessary to push down on the wheel carrier so that the strut will line up. You may need an assistant to help you. 34. Reinstall the brake calliper 35. Replace wheel and lower to ground. 36. Repeat process on the other side. 37. Refit interior. Job done, time for a brew! New shock and coil spring installed (picture from driver s side) It may be wise to take the car for a test drive before refitting the interior just in case you need to get access to the strut again.