Rear subframe bracket bolts NLA

[scenturion]

As many of you have discovered, the awful rear subframe bracket hex bolts (P/N 33311129676) have gone NLA in the past year.



On every BMW I've worked on they have been in terrible shape and many have rounded out during removal.



The original bolts are M8x1.25 22mm length. They are 10.9 rated strength, hex cap with 18.2mm flange.
They have a long threaded lead in, a cut in the threads, and what seems to be a black phosphate coating for corrosion protection.

I am about to reinforce the subframe on my car so I put some effort into finding a suitable replacement.
I found two eligible M8 22mm long bolts that might do the trick.
Both are VW/Audi parts, 10.9 rated, and intended to be used on the exterior of the car, so good for corrosion resistance.
I bought a set of both and it was ~$6 from my local Audi dealer

WHT003252 - Brake caliper bolt, e-torx, 17mm shoulder, blue locktite patch, no lead in

N91203202 - Suspension bolt, triple-square, 16mm shoulder, blue locktite patch, short lead in

Left to right, OEM, WHT, N91






I don't like that the WHT bolt does not have a lead in because I remember the bracket bolts being extremely difficult to align, but I'll try and use them for the job.

edit: if the pictures don't load in-line, see this album

[khammack]

Not sure if they actually have them in stock, but FCP Eruo seems to have them even if costly.

https://www.fcpeuro.com/products/bmw...22-33311129676

[z3forlife]

They show back ordered none in stock

[scenturion]

They show back ordered none in stock

Yeah, they've been out of stock since Jan of 2019.
getbmwparts.com shows them as "Discontinued"

[jclausen]

Call bowlin equipment co Berkeley California they specialize in metric bolts

[solimans]

On mine, replaced with standard M8X22 bolts from hardware store.

I’ve also used boltdepot.com


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[kolosy]

What’s the function of that plate? It’s called a compression strut iirc, I’m wondering what loads it sees.

[magnetchief]

What’s the function of that plate? It’s called a compression strut iirc, I’m wondering what loads it sees.

It’s connecting the sub frame to the car chassis.
So it’s seeming all that weight and stress between the two.
I personally would not use a lower quality bolt than specified.


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[kolosy]

It’s connecting the sub frame to the car chassis.
So it’s seeming all that weight and stress between the two.
I personally would not use a lower quality bolt than specified.


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the studs do that, and the subframe is sandwiched between the suspension and the body. The plate isn’t all that beefy, and neither are those bolts, hence my question.

[scenturion]

kolosy, you are correct. The compression load is taken by the nut and stud into body.
The plate boxes out the subframe stud so that it is in double shear.
It prevents the subframe stud from deflecting left/right/fore/aft at the bottom, which reduces the stress at the top of the stud.
The plate doesn't need to be thick to prevent lateral motion.

[kolosy]

kolosy, you are correct. The compression load is taken by the nut and stud into body.
The plate boxes out the subframe stud so that it is in double shear.
It prevents the subframe stud from deflecting left/right/fore/aft at the bottom, which reduces the stress at the top of the stud.
The plate doesn't need to be thick to prevent lateral motion.

yeah, that's what i figured. thanks!

[SteveG66]

I had a few stripped threads, i was able to find a split die to chase and repair the threads. If i can remember who i ordered from I'll post it.

[scenturion]

I had a few stripped threads, i was able to find a split die to chase and repair the threads. If i can remember who i ordered from I'll post it.

For me, it's the hex that strips out, not the threads. Both of these alternatives should be huge improvements in that respect, both triple-square and e-torx are much more resistant to rounding.

[PbFut]

Factory part is not a socket hex head, it's a torx and why everyone buggers them up. You can replace with a 8.8 socket hex head bolt without issue. Most hardware stores have them. Use a lock washer on it for a little extra protection since the collar is a bit smaller. I'm sure you could get away with softer bolt but most socket hex heads are 8.8 and you only need four. You talking a 5 dollar bill for all 4. Unless you are doing a restore to perfect, no need to use a 5 dollar each part even if they had them in NOS.

[solimans]

For me, it's the hex that strips out, not the threads. Both of these alternatives should be huge improvements in that respect, both triple-square and e-torx are much more resistant to rounding.

https://youtu.be/hGNp4Exurw0


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[scenturion]

Factory part is not a socket hex head, it's a torx and why everyone buggers them up. You can replace with a 8.8 socket hex head bolt without issue. Most hardware stores have them. Use a lock washer on it for a little extra protection since the collar is a bit smaller. I'm sure you could get away with softer bolt but most socket hex heads are 8.8 and you only need four. You talking a 5 dollar bill for all 4. Unless you are doing a restore to perfect, no need to use a 5 dollar each part even if they had them in NOS.

The factory bolts are most certainly hex socket head screws. Check out my pictures above or the part listing on FCP Euro.

The VW bolts are only $0.50 each. Buy some extras for the family!

[bluptgm3]

As many of you have discovered, the awful rear subframe bracket hex bolts (P/N 33311129676) have gone NLA in the past year.

I have noted in another thread that the E30 and the E36 318ti both use a similar yet different fastener that might work.
Are you familiar with realoem.com?


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[scenturion]

I have noted in another thread that the E30 and the E36 318ti both use a similar yet different fastener that might work.
Are you familiar with realoem.com?


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Yup. They used other P/Ns that are also NLA and were superseded by the 33311129676 part in the original post.

Screenshot 2020-08-31 at 9.37.51 PM.png

[320iGUY]

Lost my last post, but found this;
http://www.uturnfasteners.com/m8-1-2...xoCYX4QAvD_BwE

[bluptgm3]

GM LS Pan Bolt - zinc-plated grade 10.9 steel hex head flange screws.

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[JimZBim]

kolosy, you are correct. The compression load is taken by the nut and stud into body.
The plate boxes out the subframe stud so that it is in double shear.
It prevents the subframe stud from deflecting left/right/fore/aft at the bottom, which reduces the stress at the top of the stud.
The plate doesn't need to be thick to prevent lateral motion.

Copy and makes total sense to me. Apologies, I’m having a time trying to find torque to install these. Bentley ignores this bracket completely during rear subframe removal. Else it will just be Gudntight… thanks!

[scenturion]

Theyre standard M8 into steel nut insert, so should be ~16ft-lb