The rear end is rattlin' like a tin can full of rocks.....

[Klug]

You might have something in the drivetrain that is out if balance, causing a vibration, and causing the bolts to loosen. Do you have any other vibrations?

Well after tightening the bolts down using my MAX ARM STRENGTH, I've driven on it for over 300miles and so far everything is still tightened down. So far so good, with no other vibrations currently.

[AndrewBird]

You might have something in the drivetrain that is out if balance, causing a vibration, and causing the bolts to loosen. Do you have any other vibrations?

[jlevie]

The use of blue Locktite and/or torquing the bolts to spec should do it. Unfortunately to torque the bolts to spec you will have to drop the subframe.

[MDVDuber]

Loctite is a fine idea - but just buy yourself a good torque wrench and do it yourself.

[Klug]

Update.

So after putting in the two bolts, it seemd that all my problems went away. Then today I'm driving and start hearing a clunking in the rear when engaging 1st and 2nd gears. Sounded like the CSB was going. Went down under and found out now the other two top mounted bolts were loose...and my new bolts were not as tight as they were a few weeks ago.

Should I go the loctite route or take it in somewhere to get it air-tool'ed down to the right torque rather than just hand tightening them down. I feel this is going to keep happening.

Does everybody run into this problem when they've removed the rear?

[Cronopoulos]

Mine did the same thing, also retrofitted new hardware with blue loctite. Glad you got the problem handled... that could have potentially gone a lot worse down the road..

[Klug]

Took a look over everything else after putting about 20miles on it. Bolts looking fit and bushing are all in good shape. I'm going to keep an eye on these over the next few weeks and make sure they are not coming loose. I was going to use loctite but I didn't want to use it if I didn't have too.

Not sure why they removed those bolts to put in springs.

When I was installing my coilovers via Pellican's DIY it requires you to lower the rear diff by removing the two (even though my '89 has four) bolts that hold it up.

[ksjdan]

Wow. Found my problem.....



How the heck do TWO of these bolts get loose and come off? especially from the top! I had to drop my rear a few months back when lowering the car. I did have a highly recommended BMW shop do it....crazy.

So now i'm in need of these two bolts...any one know what size these might be? Should I use loctite?

Diff bolt backing out seems to be a common problem among newer model BMWs. Didn't know e30s do this too.

[gp.plus]

Wow. That's crazy, take a good look at your diff bushing, it has most likely been taking a beating.

Not sure why they removed those bolts to put in springs.

[Klug]

Ran to Lowes (Probably not the best automotive bolt supplier) and picked up two ones that fit perfectly. Everything is all better now.

I'm still in shock about it all...First off HOW? Secondly, if they were removed by the shop to put springs in, how did I put on over 500miles like this?

[Mr. Tasty]

fuck... lol

[Klug]

Wow. Found my problem.....



How the heck do TWO of these bolts get loose and come off? especially from the top! I had to drop my rear a few months back when lowering the car. I did have a highly recommended BMW shop do it....crazy.

So now i'm in need of these two bolts...any one know what size these might be? Should I use loctite?

[Klug]

Any chance it can be the catalytic converter rattling around? Granted I should hear it from the mid vs. the rear. If this was the case shouldn't it rattle under load and idle also?

[jlevie]

I'll investigate all the heat shields first, It does sound like something is rubbing but how is it possible to only be rubbing the drive shaft only during deceleration?

When accelerating the subframe is pushing forward, relative to the car body. But decelerating the subframe is pushing back relative to the car. Ordinarily the subframe doesn't really move, but if the subframe bushings are bad it can move. Because it has a three point connection to the car with the third point (the differential bushing) aft of the other two points (the subframe bushings) deceleration forces can cause the subframe to rock, lowering the front of the subframe. That would cause the back end of the drive shaft to move down, which could bring it into contact with the heat shield.

[gp.plus]

I'll investigate all the heat shields first, It does sound like something is rubbing but how is it possible to only be rubbing the drive shaft only during deceleration?

I would think there are different types of stress placed on the drivetrain wether you are on accel or decel, that being said my guess would be that the drivetrain is moving as opposed to the heat shield moving to rub the DT.