Anti Roll Bar (ARB) reinforcement without welding -alternate method

[inTgr8r]

This was first discussed in this thread @ post#22
At the time I considered welding the only way; & still do if repairing one that has been ripped out.

I've since given this subject a lot of thought, as I plan to upgrade ARBs on my car this year.
For those of us with our mounts still intact & looking to strengthen the mount as a preemptive measure, here is what I found out.

First
I have a welder & can do my own work, so that wasn't holding me back.
My main issue was doing welding on a perfectly good mount.
I didn't want to deal with corrosion (long term) due to welding.

That lead me to Epoxy!
I started digging around and discovered that the E46 M3 guys started using epoxy for doing rear sub-frame reinforcement about 3 years ago.
Lots of reading for you here.
**Please note the epoxy used in the first post is not the right type for our use.
This comes up later in the thread.

After some digging; 3M makes a structural epoxy that will work for us.
3M™ Scotch-Weld™ Epoxy Adhesive DP420
Spec sheet

Here's a vid demonstrating the sheer strength for 3M DP420



This makes it a simple DIY project for those so inclined.
All you need is a steel plate sized & 2 holes drilled to go over the studs.

DP420 is readily available on ebay or online hardware sources (google it)
It is an industrial spec product and not to be found @ Home depot et al.

I will be doing this myself and will gladly post a DIY but it will be spring time before I get to it.
I wanted to get this posted for those of you that may not want to wait that long.

Keep in mind... this method is intended for those that do not have any cracking or damage.

[Finnegan]

Whoa! This is a major development!

Great research/work Ian!

[beta]

Awesome stuff, thanks for sharing! Can't wait for the DIY.

[Incompatible]

Absolutely great info, thanks for posting. Waiting for DIY

[Kgolf31]

This will be awesome!

Final specs of the plate and holes will be requested so I can have a friend cut some up for me. This will be much appreciated!

[kennyfrc]

has anyone with a Z4m experienced this issue?

To my knowledge the only subframe failures in our cars were on the front sway bar mounts when stiffer bars were used.

[Beedub]

wonderful stuff ian, real contribution to the community!! well done!!

[Beedub]

Originally Posted by kennyfrc

has anyone with a Z4m experienced this issue?

To my knowledge the only subframe failures in our cars were on the front sway bar mounts when stiffer bars were used.

yes so far they only seem to fail with the beefed up bars.....

[inTgr8r]

Thanks guys, happy to help.
Next chance I get I'll lift the car & get some measurements for the front plate.

AFAIK, no one has experience rear ARB mount issues, but I'll check that out as well.

I'm planning on doing my RTABS this rear & possibly some proper adjustable camber arms.
While I'm in that deep I may just drop the subframe to inspect & look at some plates for that area as well.

I'm curious if anyone familiar with the E46 rear subframe issues knows the history of when the problems started to show.
E.g. Was it later in the cars history when mileage started to add up?

I'm wondering if BMW learned their lesson on the E46, or is this something that may yet be on the horizon for us?

[Beedub]

Originally Posted by inTgr8r

Thanks guys, happy to help.
Next chance I get I lift the car & get some measurements for the front plate.

AFAIK, no one has experience rear ARB mount issues, but I'll check that out as well.

I'm planning on doing my RTABS this rear & possibly some proper adjustable camber arms.
While I'm in that deep I may just drop the subframe to inspect & look at some plates for that area as well.

I'm curious if anyone familiar with the E46 rear subframe issues knows the history of when the problems started to show.
E.g. Was it later in the cars history when mileage started to add up?

I'm wondering if BMW learned their lesson on the E46, or is this something that may yet be on the horizon for us?

I don't think we have the same issues as the m3 rear subframe mounts, so far not one report of this issue now and these cars are getting on in age :-)

[Kgolf31]

Originally Posted by inTgr8r

Thanks guys, happy to help.
Next chance I get I'll lift the car & get some measurements for the front plate.

I'm curious if anyone familiar with the E46 rear subframe issues knows the history of when the problems started to show.
E.g. Was it later in the cars history when mileage started to add up?

I'm wondering if BMW learned their lesson on the E46, or is this something that may yet be on the horizon for us?

For the E46 it was mostly the pre-facelift vehicles (1999-2001). It was focus more so towards the sedans IIRC, not the coupes.

AWD E46s were rarely effected, post-facelift models didn't see failure as often as pre-facelifted.


My 02 w/130k miles showed no symptoms of failure (Class action lawsuit was filed for the E46 chassis, free inspection via BMW)

There really is no equation to a subframe failure.

[exdos]

Originally Posted by inTgr8r

Next chance I get I'll lift the car & get some measurements for the front plate.

Excellent find!

I fitted a set of H&R E46 M3 ARBs a few months ago, and I made and fitted some 5.5mm thick steel shims between the front ARB bracket and the chassis, which I think should prevent chassis flex and metal fatigue causing tearing. I didn't want to weld the shims to the chassis for the same reason that you've mentioned (rust developing around the welding point), but now you've brought this method to everybody's attention I'll definitely use the epoxy glue to stick my shims to the chassis.

I've got a spare shim lying around, so I'll scan it on my photocopier and upload the image in this thread so it can act as a template for anyone who wants to strengthen the chassis.

When I was installing the rear ARB, I had a very good look at the rear subframe and chassis, with the idea of possibly reinforcing the points of attachment. I thought the construction looked fine with no obvious points of weakness, so I left alone.

[Beedub]

Originally Posted by exdos

Excellent find!

I fitted a set of H&R E46 M3 ARBs a few months ago, and I made and fitted some 7mm thick steel shims between the front ARB bracket and the chassis, which I think should prevent chassis flex and metal fatigue causing tearing. I didn't want to weld the shims to the chassis for the same reason that you've mentioned (rust developing around the welding point), but now you've brought this method to everybody's attention I'll definitely use the epoxy glue to stick my shims to the chassis.

I've got a spare shim lying around, so I'll scan it on my photocopier and upload the image in this thread so it can act as a template for anyone who wants to strengthen the chassis.

When I was installing the rear ARB, I had a very good look at the rear subframe and chassis, with the idea of possibly reinforcing the points of attachment. I thought the construction looked fine with no obvious points of weakness, so I left alone.

yesss!!! perfect get on this john and report back, whats your feeling on the Rear subframe mounts on the z4m???? im guessing we shouldnt need to worry ;-)

[inTgr8r]

Originally Posted by Kgolf31

For the E46 it was mostly the pre-facelift vehicles (1999-2001). It was focus more so towards the sedans IIRC, not the coupes.

AWD E46s were rarely effected, post-facelift models didn't see failure as often as pre-facelifted.


My 02 w/130k miles showed no symptoms of failure (Class action lawsuit was filed for the E46 chassis, free inspection via BMW)

There really is no equation to a subframe failure.

Great, thanks for the info.
Sounds like we should be OK then.

[inTgr8r]

Originally Posted by exdos

Excellent find!

I fitted a set of H&R E46 M3 ARBs a few months ago, and I made and fitted some 7mm thick steel shims between the front ARB bracket and the chassis, which I think should prevent chassis flex and metal fatigue causing tearing. I didn't want to weld the shims to the chassis for the same reason that you've mentioned (rust developing around the welding point), but now you've brought this method to everybody's attention I'll definitely use the epoxy glue to stick my shims to the chassis.

I've got a spare shim lying around, so I'll scan it on my photocopier and upload the image in this thread so it can act as a template for anyone who wants to strengthen the chassis.

When I was installing the rear ARB, I had a very good look at the rear subframe and chassis, with the idea of possibly reinforcing the points of attachment. I thought the construction looked fine with no obvious points of weakness, so I left alone.

Good stuff, thanks!

[exdos]

Originally Posted by Beedub

whats your feeling on the Rear subframe mounts on the z4m???? im guessing we shouldnt need to worry ;-)

Byron,

I don't think there's anything to worry about with the Z4MC, it was made long after the problem in manufacture became apparent in the E46. BMW tends to learn from it's mistakes.

As you know, I also have a Z3MC, and there is a real problem of boot floor tearing with that car, there are some real horror images of it, and in comparison to the Z3MC, the Z4MC is a MUCH stronger car of an altogether different design and of better engineering integrity. Relax!

[exdos]

I'm more organised that I thought and I could readily lay my hands on the template.

Here you go! Obviously, it's reversible L <--> R

[Finnegan]

Wow! Thanks.

What a great thread!

[Beedub]

Originally Posted by exdos

Byron,

I don't think there's anything to worry about with the Z4MC, it was made long after the problem in manufacture became apparent in the E46. BMW tends to learn from it's mistakes.

As you know, I also have a Z3MC, and there is a real problem of boot floor tearing with that car, there are some real horror images of it, and in comparison to the Z3MC, the Z4MC is a MUCH stronger car of an altogether different design and of better engineering integrity. Relax!

Ok ok ok ill relax, tend to get abit worried over things that have affected older models, as a car I plan to keep I'm trying to remedy potential issues ASAP, I will definitely be doing the ARB mounts with this epoxy resin, that stuff sets like concrete , great find Ian.

[inTgr8r]

Originally Posted by exdos

I'm more organised that I thought and I could readily lay my hands on the template.

Here you go! Obviously, it's reversible L <--> R

Thanks for the template!
That really helps.

We could use a few more dimensions for the stud holes, if that's possible.
If not I'll add them when I get the car up on the lift again.
The studs are M8 so that will help with hole size.

[exdos]

Originally Posted by inTgr8r

Thanks for the template!
That really helps.

We could use a few more dimensions for the stud holes, if that's possible.
If not I'll add them when I get the car up on the lift again.
The studs are M8 so that will help with hole size.

When I measured the stud centres with a pair of large dividers, they were 90mm apart. If you can drill with your holes at exactly 90mm apart, then you should be able to use holes in the shim which are 8mm each. If the shim doesn't fit onto the studs, just drill one hole at 8.5mm and test fit, if this is not right, then drill the other hole at 8.5mm, and keep increasing the holes by 0.5mm, and so on, until the shim fits with the smallest holes.

in any event, once you use the resin to attach the shim, some of the resin will fill any space in oversized holes, but I don't think that's critical. It's increassing the thickness in the chassis region, preventing flexion, which is what we're trying to achieve.

The shim which I scanned has been fitted on my car, so if you use the centres of those holes, and use a 8mm drill as your starting point, then stepping up in 0.5mm drill sizes, should soon produce a shim that fits.

If I were to weld the shims in place, I certainly would want to weld the shim to the studs, because that would tend to weaken the studs.

[Beedub]

Originally Posted by exdos

When I measured the stud centres with a pair of large dividers, they were 90mm apart. If you can drill with your holes at exactly 90mm apart, then you should be able to use holes in the shim which are 8mm each. If the shim doesn't fit onto the studs, just drill one hole at 8.5mm and test fit, if this is not right, then drill the other hole at 8.5mm, and keep increasing the holes by 0.5mm, and so on, until the shim fits with the smallest holes.

in any event, once you use the resin to attach the shim, some of the resin will fill any space in oversized holes, but I don't think that's critical. It's increassing the thickness in the chassis region, preventing flexion, which is what we're trying to achieve.

The shim which I scanned has been fitted on my car, so if you use the centres of those holes, and use a 8mm drill as your starting point, then stepping up in 0.5mm drill sizes, should soon produce a shim that fits.

If I were to weld the shims in place, I certainly would want to weld the shim to the studs, because that would tend to weaken the studs.

John how thick is the plate???