3.25 lsd shredded hex bolt found inside

[The Bimm]

Can any one explain to me why I found a little hex bolt inside my diff while changing my fluid last night? Should I be worried? . I'm opening it up anyways, but would like to know if it's happend to anyone else.

[jlevie]

Yes you should be worried. Get the cover off and look for where the bolt came from.

[The Bimm]

Haha daymmmmmm that sucks. Who knows how long I've been driving without it well looks like a project for the weekend. Thanks man

[FredK]

Yes. It is a lot more common on E36 limited slip diffs, where the socket head cap screws that hold the LSD capsule together back out. There are 8 socket head cap screws that hold it down. They are M8x1.0x16 screws. They are available through MSC, Fastenal, and also the dealer (PN 33147740005). They are finer pitch thread than the normal M8 screws you find on BMWs.

The solution is to use locking compound on the screws upon reinstallation.

It's possible to remove the LS unit without dropping the whole diff. You need to disconnect the halfshafts, remove the rear cover, remove the axle stubs, remove the side plates (being sure to keep the plates and shims on each side of the diff in order, right side and right shim need to be reinstalled on the right side).

Hopefully the threads in the diff weren't damaged by the bolt loosening. If they weren't the best thing to do is to remove one bolt at a time, put some solvent into the hole, and blow it out with compressed air, being careful not to blow it back into your eyes, and reinstall the bolt with Loctite on it to a torque appropriate for the grade of fastener you're using.

[The Bimm]

Thanks for the help man I'll be doing this Sunday. I might just take the whole diff out to inspect everything else on it.

[jlevie]

No need to pull the differential. Short of gear mesh and end play checks, which require the differential on the bench and special equipment, you can fully inspect the differential by removing the cover.

[The Bimm]

So I can just pull the cover off the diff, and will be able to see the lsd capsule where the bolt came out from?

[FredK]

Yes.



On the left side of the ring gear you'll see that it's bolted to the LS carrier with a bunch of really large M14 bolts. Inboard of those bolts are the smaller M8 capsule socket head cap screws. You'll obviously need to rotate the diff to see all of the fasteners.

[The Bimm]

Alright cool man thanks for the pic, and the advice.

[Wanganstyle]

Honestly if you have a bolt head hanging out in the oil the clutch discs and steels will show some nasty wear.

the 1995 e36m was notorious for this; it often leads to broken top caps and melted internals: many photos of this on BFC and the like.

The little bolt heads also enjoy destroying the ring and pinion set.

I guess bmw decided in 1994/5 that loctite was too expensive to use on m3's

If it's been ran prolonged and too many bolts are loose strange damage can happen to internal parts. This unit internal set also had contact hit while wheel to wheel racing and further complicated the damage.



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