What bolts for attaching driveshaft to diff?

[FinalD]

So on Sunday this happened:



Despite them all having been done up tight they managed to come undone, quite scary really as this happened at sub 5mph, the day before I'd been on the motorway in the rain. If it had happened then I'd hate to think of the total result!


Anyway, one has sheered off about 10mm from the end, all the rest are ok. However I'd rather replace all of them with brand new items and threadlock them into place so that this doesn't happen again. I've had a look on realOEM and found this page:

http://www.realoem.com/bmw/showparts.do ... g=33&fg=25


It lists two parts:

Torx screw - 33211227279
Fillister head screw - 07119919620

Now, one is £10 and the other £0.80. Google says fillister head screws are just that, screws and not bolts. The parts I want to replace are internal hex / alan key bolts.

My car is a 1988 2.5 cab, anyone know which bolts I need to order from Cotswolds/my local BMW dealer?

[DanThe]

The torx screw is the type thats notoriously difficult to use, you get much better purchase with the cap screw which is part no 07119919620 or -
http://www.cooper-bmw-parts.co.uk/index ... virtuemart
78p indeed
You could probably get them cheaper at a fasteners shop if you take a pattern

The only reason they have come loose is because they were not tight enough, you dont need threadlock, ive seen plenty of E30's with loose driveshaft and diff bolts, seems to be a common problem with the repairers

[Brianmoooore]

Two types of bolt are interchangeable - doesn't matter which you use. Female hex. is the early type, which was superseded by a male torx.
If your bolts had been torqued correctly, they would not come undone or break. I suspect the driveshaft wasn't seated correctly, so the bolts were under tightened.
I'd tighten up the exhaust bock box clamps as well, while you're under there, before that falls off as well!

[FinalD]

That's the thing, I'm 100% sure I did them up he-man tight...I'll admit I didn't torque wrench them but they were done up to the level of 'if I do this more it'll snap the head off'.

I'd rather apply some threadlock to ensure that it doesn't happen again, in case I have been a pansy when doing them up. I'll make sure to torque them correctly though that's for sure (although have to drive it 90miles to get the torque wrench...).

Are the 78p ones actually screw heads, normal headed bolts or hex/torx/alan bolts? As normal screw head seem like a bad idea.

E: The exhaust box clamp is an after market thing, it is tight but doesn't seem to want to bend to the shape of the box...I'll try and do it up a bit tighter though.

[Grrrmachine]

Annoyingly I had the opposite issue about two weeks ago, destroying a bolt and needing to order six more (minimum order). I just took the part number from RealOEM without paying much attention, and ended up with the Torx bolts instead of the Allen head ones

That was part number 33207572716, which don't cost anywhere near 10 quid each.

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I know this has already been resolved, but people searching for this may miss it in E30 chat if they filter their results to the tech section only.

[FinalD]

Cheers for moving, wasn't too sure which section would be best for replies.


I have an idea why vibrations may have assisted in undoing my bolts.....





I think I need a new diff casing!

[bmw9818]

wtf ^

i allways use medium loctite when reassembling majority of bits on the car esp driveshafts/prop and suspension and steering components, brakes, etc for £3 a bottle you cant go wrong

[FinalD]

Yeah, that was my reaction when I crawled under the car! I have no clue how it happened as that is some serious damage!