My 1986 E28 528e is in exceptionally good condition but right before I bought it, it was parked for a many years. I have learned that this sort of thing causes a few typical points of failure. That includes the universal joints in the drive shaft. I had something similar happen on my 1973 Volvo 145, that I parked for several years — a not-so-smart thing to do.
The symptom on the BMW manifested itself with a pretty severe seat-of-the-pants (as opposed to front-end) shimmy at low speeds. My local drive shaft fix-it place diagnosed the problem as the front universal joint being a) completely frozen up and b) non-serviceable. Were the latter not the case, a $15 part would solve the problem, such as was the situation for my Volvo 145.
The last time I heard that the drive shaft on my car was non-serviceable was some years ago, on my 1987 E30 BMW 325. The part cost me $500. So, now that I’m cheerfully in the used-parts business, I could solve the problem myself, this time.
The donor car for my 1986 528e was a 1984 automatic 528e. I haven’t as yet measured and analyzed precisely how the drive shafts differ between stick shift and automatic 528e cars but I’ve been told they are different so I made sure the donor car also has an automatic transmission.
Before removing the drive shaft, it’s a good idea to get the rear of the car up on jack stands. Chock the front wheels because the rear wheels will have to move freely.
Get underneath the car and find the 17mm nuts at either end of the drive shaft, and douse them with penetrating oil such as WD-40 or PB Blaster. That way, the chemicals have time to do their work while you focus on the exhaust, heat shield and center support.
Removing the drive shaft requires first removing the exhaust since that’s pretty much directly below the drive shaft.
Next, there is a large heat shield whose six nuts are best removed with a 10mm socket and a short extension. Some large washers prevent the nuts from pulling through the heat shield, and once you have removed the washers, the heat shield should be ready to fall on your head, which shouldn’t hurt too much since it’s fairly light.
With the heat shield removed, the center support becomes visible. Its two nuts are best loosened with a 13mm socket and a short extension. The ideal approach is where you loosen the nuts to where you can remove them by hand, but leave them in position … for now. That way, the drive shaft doesn’t sag in the middle.
Recruit an assistant (preferably one with pretty shoes, feet, ankles and calves since you’ll be underneath the car and that’s probably all you’ll be able to see). I recommend http://www.qupidshoes.com/ as a supplier of assistant footwear — if you’re going to be working on your car, you might as well enjoy it. Ask her to put the transmission into “park.”
Loosen one nut using a high-quality 17mm ring wrench, ideally a ratcheting one such as those that are part of the Sears Craftsman range. You definitely don’t want to strip this nut. Remove the nut.
Ask your assistant to put the transmission into “neutral.” Manually rotate the drive shaft ninety degrees and then ask her to put the transmission into “park.” Remove the next 17mm nut.
Repeat this process for the remaining two nuts, and then repeat the process for the four 17mm nuts at the front of the drive shaft. You might find the transmission-related parts to be in the way. My donor car had already been stripped in that respect, so that wasn’t a problem for me.
Thank your assistant, and compliment her pretty feet and calves. Ponder the irony that if you’d complimented her shoes, she would probably have liked the compliment more yet. Gently dismiss her.
Next, put something soft (not your assistant) under the drive shaft in case it falls to the ground, which will be the case if things go according to plan. Remove the 13mm center support nuts so that the drive shaft sags. Gently pry at the front yoke with a large flat-tip screwdriver until it separates from the transmission. Try to avoid having it fall on you as it comes down.
Do the same for the rear yoke, and pull the drive shaft forward and out, so that it too falls down, again ideally not on you.
You’ll notice that the drive shaft is large but relatively light, and that in the center, the front and back halves are connected via splines. I’ve been told that it’s a good idea to mark where and how the two pieces fit together, as to their relative positions. Better yet to not even separate the two pieces.
Re-installation consists of taking the part to your local drive line shop and paying them to re-install the part, which might include seeing if it’s in balance and doing something about it, if it’s not.