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Subject: DIY: How to replace the front shocks absorbers in a '92 750iL (long) Author: DavidC (moderator) : member since December, 2003 : 11918 posts Posted on: 2005-01-06 22:55:20

This is one of my longest, yet most detailed, posts on do-it-yourself BMW repairs. The front shocks in my ’92 BMW 750iL were completely shot and needed replacing. I thought that this would make an excellent BimmerBoard topic, so I embarked on a mission to learn how to do it and document the process. Though this procedure is for a ’92 E32 750iL, everything in it applies to the other 7’s as well, including the older e23’s and the newer e38’s. It applies to all of the other BMW models that use strut-type shock absorber inserts as well, though I’d recommend checking torque specs and part numbers for the other models.

In this article, I’ll take you through the steps of removing and replacing the front shock absorber inserts. Extensive photos with annotations are included at every point. This somewhat mysterious process is surprisingly easy once you see it done. Anyone with the tools and the time can handle the job, which I would rate at a skill level of 7 on a scale of 1-10, mostly because several of the parts are heavy and because compressing the springs can be an intimidating experience.

Speaking of tools, you’ll need the following:
Floor jack and jack stands (at least 2 1/2-ton)
Air compressor and an air wrench, 1/2-inch-drive (you could use hand-tools, but air-tools are much, much easier)
Socket wrench, 3/8-inch drive
Torque wrench (with a range of at least 16 ft-lbs to 96 ft-lbs)
Large flat-blade screwdriver
Large pipe wrench
Spring compressors (available for rental at most auto-parts stores)
1/2-inch-drive sockets (23mm, 19mm, 17mm, 13mm)
6mm hex bit, 3/8-inch-drive
5mm hex bit, 3/8-inch-drive
2 fluid ounces of motor oil (any weight will do)
Plenty of paper towels


With the transmission in Park and the parking brake engaged, position the floor jack so that the foot of it presses against the steel horizontal cross member beneath the engine. Be careful to avoid the oil pan. The foot of my floor jack is bowl-shaped, so I placed a block of wood in it.


Raise the front end of the car and place jack stands underneath the jack points of the car for safety.


Use a 17mm socket to remove the 5 lug nuts then take off the wheel.


A view of the hub/rotor/caliper assembly with the wheel removed.


Remove the two 19mm caliper-to-strut bolts on the back of the hub.


Slide the caliper hydraulic hose with its rubber grommet out of the clip on the strut tube.


Slide the caliper assembly off of the rotor and set it aside on a bucket. Don't let it hang from the rubber hydraulic line.


Remove the rotor retaining screw with a 6mm hex bit and then remove the rotor.


Use a 5mm hex bit to remove the retaining screw for the ABS sensor.


Pull out the ABS sensor. It will probably be very dirty so this is a good time to clean it.


Slide the ABS sensor wire with its rubber grommet out of the clip on the strut tube.


The right front wheel doesn't have it, but on the left front wheel there will be a brake pad sensor that must also be disconnected. Follow its wire and slide it and its rubber grommet out of its clip on the strut tube as well.


Remove the 17mm nut to release the stabilizer bar connecting link at the point shown above. I would've preferred to detach it at the other end, nearest the strut, but I couldn't get an air ratchet in there.


Once the nut is off, slide the stabilizer bar out of the hole in the direction shown.



Next, detach the strut assembly from the steering arm below it. There are three 19mm hex bolts that must be removed. You'll have to turn the steering wheel to make room to access two of the bolts.


Now go on top and use a flat-blade screwdriver to pry off the plastic cover on the strut tower. Just push in gently from the side and then lift up.


Make a mental note of the height of the studs above the nuts on the three bolts on the tower and on the bolt at the center (but don't touch the bolt at the center). It's a good idea to use a grease pencil to mark the location of one of the bolts (mark the top of the stud and the painted metal around the corresponding hole) to make re-insertion easier later. Remove the three 13mm self-locking hex nuts from the strut tower. When reinstalling, be sure to use new nuts.


From below, pull down on the strut to extract it from the mounting holes in the tower above. You may need to insert a flat-blade screwdriver to pry the upper and lower halves apart as shown.


Remove the strut assembly from the car.


A view of the steering arm without the strut assembly. You can easily see the three mounting holes for the strut and the other mounting hole for the stabilizer bar connecting link.


A view of the old strut removed from the car.


Carefully position your spring compressors on the spring so that they're SAFE! You don't want these things to slip around the coils and fly off. I suggest placing the strut on the floor, or a workbench, and pointing it in a safe direction (don't stand in front of the spring). That way, it can't launch itself into the air should something bad happen. I used an air wrench to compress the springs. It’s scary how much you have to wind them down – respect the spring!


Once the spring has been sufficiently compressed to take the pressure off of the top plate, use a 23mm socket to remove the nut at the top of the strut. Then take note of which end of the spring is top and which is bottom. My springs were marked with yellow paint near the bottom. Remove the spring from the strut then lay it back down and carefully unwind the spring compressors. Even though it seems unnecessary, it simplifies things later because it’s easier to reposition the spring compressor when putting everything back together.


A view of the old strut with the spring removed.


Remove the black rubber stop on top. It has a metal cap on top which we'll reuse.


Remove the flexible rubber boot as well. You'll see a plastic ring near the bottom to which we'll secure the new boot.


Lay the strut on its side. The shock insert within the tube is retained by a screw-on collar. The collar usually has a metal cover over it, as shown above. Use a pipe wrench to turn the cover so that the holes line up with notches in the collar, then use a flat-blade screwdriver to pry the cover off of the collar.


Now the retaining collar can be removed. I found this to be the most time-consuming aspect of the project. It took me about 20 minutes to get the strut off of the car, but nearly 2 hours to get the darn collar loose as it was rusted tight. The replacement shock inserts come with a new retaining collar, so don't worry about damaging the one on the tube, but don't damage the threads on the tube, obviously.

I've heard some say that heating the collar will loosen it, based on the idea that the softer metal of the collar will expand more quickly than the harder metal of the strut tube. However, in my case, the solution was generous application of PB Blaster rust dissolving spray and a couple of 24-inch pipe wrenches.


Once the collar is removed, the old strut insert can be pulled out.


Be careful not to spray oil/fluid all over the place, though. My old shocks were completely shot. All of the seals in them had worn out, allowing the fluid in them to seep out into the shock tube. Clean the inside of the strut tube with a paper towel.



There seems to be a bit of confusion about the necessity of adding oil to the strut tube when replacing the shock insert. The Bentley's manual specified adding 30ml (1 fluid ounce) of motor oil for cooling when using hydraulic-type shock inserts. It didn't say anything about that for gas-type shocks. I've read quite a few discussions on the subject and the general consensus seems to be that adding the oil is a good thing, regardless of the shock type. Some people have reported that their shocks are noisier without the oil. I added 30ml of Castrol 5W30 motor oil even though my Boge/Sachs replacement shocks had a "gas" sticker on them. Here's to smooth shocks!


Install the new collar onto the strut tube. The Bentley's manual says to torque it to 96 ft-lbs. I don't have a socket large enough or deep enough to fit on the collar with the shock installed, so I just tightened it with a pipe wrench until it was REALLY tight. I also put some anti-seize compound on the collar threads. Note the new 23mm nut at the top of the strut. It came with the new shock.


The old and new rubber stops that go on the top of the shock.


The old and new flexible rubber boots which protect the shock from dirt and debris.


Install the new flexible rubber boot and the rubber stop onto the new shock. Put the metal cap that we saved earlier on the top, concave side down as shown.


Re-compress the spring so that you grab five coils and crank it down. Again, BE CAREFUL and pay attention to safety! Don't be afraid to loosen the compressors and start again. It took me several tries to get everything positioned properly so that the ends of the spring would mount properly.

Replace the lower rubber spring pad (part # 31331124322).


Replace the upper rubber spring pad (part # 31331135589). Note that I used the 10mm thick version. There's a 3mm thick version (part # 31331128523) used on some sport models.


Once the spring has been compressed sufficiently, place it onto the strut assembly, taking care to make sure that the spring is oriented correctly and that it seats properly into the lower rubber spring pad. In this photo, I didn't have the spring compressed enough, so I had to decompress it and do it again so that I grabbed five coils on the right side.

Install the upper guide support along with the new rubber upper spring pad onto the spring, guiding the shaft of the shock though the hole in the center. Attach your new
23mm self-locking hex nut and tighten it down so that the top of the threads is flush with the top of the nut. Then tighten the nut to 49 ft-lbs. You may need to push down the rubber stop and hold the shaft to keep it from spinning. Alternatively, you can insert a hex wrench in the hole at the top of the shaft and tighten the nut with an open-ended wrench.


Put the entire strut assembly back into the wheel well and guide it up into the strut tower. It helps to have someone press down on the steering arm while fitting the strut back into place.


Insert the three 19mm bolts at the bottom and torque to 81 ft-lbs. Put the stabilizer bar connecting link back into position and replace its nut. Torque to 43 ft-lbs.


Secure the strut to the car body with your new 13mm self-locking nuts on the top of the tower. Torque to 16 ft-lbs. Reinstall the plastic cap over the center area.


Apply anti-seize compound to the front of the hub where it meets the rotor, then reinstall the brake rotor and its 6mm hex retaining bolt. Torque to 12 ft-lbs.
Reinstall the brake caliper assembly with its two 19mm bolts. Torque to 81 ft-lbs.
Reinstall the ABS sensor and its 5mm hex retaining bolt.
Insert the rubber grommets for the brake, ABS and (for the left side) the brake pad wear sensor into their clips on the strut tube.
Reinstall the wheel and lug nuts; torque to 74 ft-lbs.

Shocks should always be replaced in pairs, so do the other side then take your car out for a slow test drive. Listen for any squeaks or pops that might indicate that something needs tightening or if something is rubbing (such as the brake shield on the back of the caliper or the shield on the stabilizer bar connecting link).

When done, pat yourself on the back for a job well done, for learning skills and for saving a bundle of money. I was recently quoted $885 by a nearby BMW dealer for replacing the front shocks, including parts and labor. I paid just $250 for all the OEM Sachs/Boge parts, including all the replacement rubber pieces and nuts, including shipping.

David Cecil, KI4GZR
'97 740iL, 127k miles
'92 750iL, 77k miles
'86 735i, 95k miles

www.e38.org has links for everything about your BMW 7-series automobile

• DIY: How to replace the front shocks absorbers in a '92 750iL (long) (pic) - DavidC 2005-01-06 22:55:20 (38612 views)
  • Re: DIY: How to replace the front shocks absorbers in a '92 750iL (long) - mberg75 2009-06-25 13:42:15 (122 views)
  • Re: DIY: How to replace the front shocks absorbers in a '92 750iL (long) - know1uknow2 2005-12-26 23:44:27 (1084 views)
  • Re: DIY: How to replace the front shocks absorbers in a '92 750iL (long) - fred 2005-01-17 23:28:40 (1208 views)
    • The first one took the better part of the day, but I was going - DavidC 2005-01-18 02:05:33 (1473 views)
      • Re: The first one took the better part of the day, but I was going - mappslr 2005-01-20 01:21:00 (1050 views)
        • I couldn't see a downside to adding the oil, so I did it. - DavidC 2005-01-20 11:36:04 (1074 views)
  • Re: DIY: How to replace the front shocks absorbers in a '92 750iL (long) - mappslr 2005-01-17 15:48:25 (1171 views)
    • Yes, I believe it is as long as you don't have the EDC system. (nt) - DavidC 2005-01-17 19:43:18 (1343 views)
      • Re: Yes, I believe it is as long as you don't have the EDC system. (pic) - mappslr 2005-01-17 23:25:24 (1746 views)
      • Re: Yes, I believe it is as long as you don't have the EDC system. - mappslr 2005-01-17 23:18:33 (1106 views)
  • Nice!! Good pics to! (nt) - ED 2005-01-08 19:35:41 (982 views)
  • excellent , thanks David (nt) - shogun 2005-01-07 00:19:19 (860 views)
    • Re: excellent , thanks David - japhrodisiac 2005-05-21 03:25:14 (723 views)