Propshaft Bolts

GreatOldOne · #1 4th March 2008, 21:23

Hi guys - looks as if my propshaft will be arriving imminently, according to the latest from Marlin. With that in mind, what strength bolts do I need for it? Will 8.8s do, or will I need some 10.9s?

Ta,

Jason

peterux · #2 4th March 2008, 22:00

I used standard 8.8's but don't remember what the BMW bolts were?

GreatOldOne · #3 5th March 2008, 07:04

Real OEM has them down as 10.9s:

http://www.realoem.com/bmw/showparts...11&hg=26&fg=10

Code:

04 HEX BOLT     M10X50/10.9     3  06/1988 26111209498 
05 HEX BOLT     M10X54-10.9-PHR 3  06/1988 26111225744 
16 KNURLED BOLT M10X25          4          26111206718

Looks like I need to go shopping...

GreatOldOne · #4 19th March 2008, 16:44

Right, my propshaft turned up yesterday. I've put it in for now with 8.8's, as the BMW ones are way too long - and I'm having real problems trying to track down some 30mm M10 10.9 bolts that will do the job (no one seems to sell them on line in quantities less than a 100)

Am I obsessing? Do I need 10.9s? or will 8.8s do?

Also, the rear flange that mates to the diff - Mine has a flat mating surface around the edge, where the bolts go - but in the centre there is a raised section. When in place, this section prevents the two flat surfaces from meeting... Is this right? do I need some sort of packing between the two?

MartinClan · #5 19th March 2008, 19:48

That doesn't look right to me. You have to be very careful with anything associated with the propshaft when you consider it can turn at 6000+ rpm (or 600 times a second - sounds even faster lol) It would be a good idea to compare the propshaft flange with the original one from the donor.

Where did your propshaft come from? I had my propshaft made by a specialist using the original real UJ and flanges. Needless to say it fitted OK with the BMW bolts. There's some pics of the propshaft on my website that might help.

Edit: Sorry they don't help - no close up of the rear flange - just the front one...

Robin

GreatOldOne · #6 19th March 2008, 20:05

Nope, that's the rear flange, bolted to the diff.

I got my prop from Marlin.

peterux · #7 19th March 2008, 20:37

The raised circular flange on the propshaft should fit snugly inside the recess in the diff flange. It makes it hub-centric.
Mine was a bit of a tight fit but did fit flush once I tightened up the nuts and bolts.
It might be just paint on the propshaft flange? From memory this flange is not painted on the BMW original propshaft.

Peter

GreatOldOne · #8 19th March 2008, 20:43

I'll take another look tomorrow.

GreatOldOne · #9 1st April 2008, 12:12

My propshift fits like a glove - Just pete said, as soon as you torque up the bolts, eveything seats fine.

I've just used normal 8,8 bolts like the rest of you, but whilst noodling around in the garage I cam across my old front brake caliper bolts - which are M10, 10,9 grade and are exactly the right size for the gearbox flange end, a bit long for the diff end.

So if I get a little paranoid about it, I may just order some more of the caliper bolts and use those. There's no reason not to use them, is there? 10,9 bolts are 10,9 bolts, reagrdless of where they where originally used on the car.