Engine mount bolts

M

Mos6689

Member
So I’m trying to do as much preventative work as possible, which has brought me onto this.

I’ve been reading about the engine mount bolts failing due to being crap. I’ve bought 6/8 motorsport bolts from main dealer but they no longer do the 35mm bolts, discontinued.

I read that beedub said somewhere it was just a specific batch of bolts in the US but the more reading I do, the more I find these failures all over the world.

Has anyone done this over here and if so where did you source the bolts? I’ve been reading about what coating is acceptable for automotive use and this has lead me to looking for geomet treated bolts only. Found a website that does these in the correct tensile strength & size, but they’re only partially threaded. Is that going to be acceptable? The motorsport ones are fully threaded so I’m trying to find a like for like. Is there a different finish that would be acceptable?

The motorsport ones I need are for the left hand side, M8x35mm 10.9 hex head. Can’t find any information on what treatment they had and dealers couldn’t provide me with any information.
 
When I last had my car at RBM Hampshire earlier this year, I asked them to change the bolts as preventative maintenance.

At the time, I believe all bolts were available from BMW (Cross referenced the part numbers from Realoem) and when Ross changed them, none of the existing bolts were loose.

Glad it has been done for peace of mind though.
 
I’m actually getting Ross to do mine as well. Did you use the upgraded motorsport bolts though? Or just like for like 8.8?
 
Thanks.

Upgraded 10.9 strength bolts are part numbers:

07119913673 M8x35mm you need 2 of these. These are the ones BMW discontinued.

07119913653 M8x25mm you need 6 of these. These they still do, for now.

07119903078 Washers.

31106772199 8xReinforcement plate bolts. These are standard but you do need to swap them as they’re one time use.
 
From looking at a previous thread on here, the following is what I had discussed with Ross.

https://www.realoem.com/bmw/showparts.do?model=DU92&mospid=49422&btnr=22_0064&hg=22&fg=05&hl=6

"You'll need six of number 3 (07119905724) and two of number 10 (07119905533). Four of the number 3s are used on the intake side of the engine. The other two number 3s go in the rear upper and lower holes of the exhaust side bracket. The two number 10s are slightly longer at 35mm and are for the front upper and lower holes (they are longer because in addition to securing the braket to the engine, they also secure the Vanos accumulator mount to the bracket)"

The above was from the following thread: https://z4-forum.com/forum/viewtopic.php?t=59449

I can't seem to find the invoice in my e-mails so will ask Ross to re-send.
 
No worries. I’m going to see him in a few days so I’ll discuss when I get to RBM. Thanks for having a look though!
 
If anyone does come across this in the future and requires the same bolts that bmw no longer do, I sourced them from here:

https://nutsandbolts.co.uk/index.php?_route_=M8-x-35mm-Flange-Hex-Bolt-DIN-6921-Metric-10-9-Grade-Geomet-500-Partially-Threaded&search=M8%2035mm

These aren’t fully threaded but that wasn’t a problem & to be safe I used nordlock stainless steel washers.
 
Beedub said:
Well done !! preventative work is always best!
Click to expand...

100%! My original bolts weren’t poking out or anything awful like the horror stories I’ve seen but Ross at RBM, did ask the tech who swapped them over & he did say a couple of the bolts were very easily removed/loose. So well worth the £50 or so it cost!

Well worth mentioning as well, it’s been said already but RBM in Hook, top quality specialist. Reasonably priced & well documented/photos of all the work undertaken! Anyone looking for a local specialist down these ways, look no further. Won’t be long until these guys are booked up for months like Reddish & Munich Legends!
 
You must log in or register to reply here.
Back
Top Bottom