E36 diff query

[V8mate]

I've bought a new diff with a known fault: the bolt hole at the flange end has clearly had a loose-fitted bolt and has worn the hole oval. I intened to drop the diff over to an engineering firm to get them to weld the hole up and rebore it, but I've ordered a new bolt from BMW and it won't go in at all.

So, before I spend any money getting this bit repaired, I want to know what function this bolt performs. Is it just some kind of 'damping', so I could just leave it out altogether?

It's part 16 in the plan and the obvious bit in the photo. Any clues/advice?

[pat_y]

hmm, same part number as a bolt on the diff mounting cradle, suspect it might be number 17 in the below drawing

[V8mate]

Ah - good sleuthing. So it does look like a vibration suppression mount.

I might just not bother then...what's the worst that could happen?

[pat_y]

or just fit a longer version and chuck a large locknut on the end, i would fit it personally just to be sure but i'm a picky bugger anyway.

[Salom]

You must fit that bolt, do not drive the vehicle without it, it stops the diff rotating and has worn due to enthusiastic driving by the previous owner, either use a smaller bolt or drill the hole out to fit the new one..

[V8mate]

Salom said:

You must fit that bolt, do not drive the vehicle without it, it stops the diff rotating and has worn due to enthusiastic driving by the previous owner, either use a smaller bolt or drill the hole out to fit the new one..

OK. I shall heed your advice. Especially as this is on a track car where 'enthusiastic driving' will be the norm.

I'm just perplexed as to why the new bolt won't go into the hole at all. You'd think that it would just fall in and wobble about but you can't even poke it in slightly.

[ian_touring]

V8mate said:

-snip- I'm just perplexed as to why the new bolt won't go into the hole at all -snip-

Maybe previous owner bodged it with a too-small bolt, which allowed a degree of movement, which in turn made the hole oval?