M3 Rear ARB installation...

[Steve_M]

I ordered an M3 Coupe bar (22.5mm) from HP Autowerks a couple of months ago and finally got around to installing it. I did a ton of research on dropping the rear sub frame, tips, tricks, problems, what to look for, what not to do, etc., and that part of the job went pretty darned well.

Snaked the old wimpy bar out and the new one in and took a celebration break. I told my buddy we were on the down hill slide, now.

Well...

We had looked at the bushings after I took all the parts out of the box before we dropped the sub frame and remarked on how small the hole was. We really didn't think all that much about it, figuring we would just squash all that rubber under the bracket with the bolts once we got it in place.

If anyone else has done this job, then they know where I'm going with this.

The only good pictures I found were at ECS Tuning.

Bottom Half - http://www.ecstuning.com/ES248877/ES59206/
Top Half - http://www.ecstuning.com/ES59207/
Bracket - http://www.ecstuning.com/ES59208/

If you look at the bottom half, the square section that rests against the sub frame and extending up around the sides are a very hard rubber or plastic. There is a recessed section, then a rim inside that. That rim contains a metal half circle piece that is covered with rubber, then inside that is a softer rubber. Top half is similar and mates with the bottom half. Once you try to put it into the bracket, there are two small triangular catches that clip into the bracket to hold it, I guess.

If you mate the two halves together in your hand and measure the hole, it is a bit over 18 mm. The only give you have is inside the rim with the metal circle which is around 24 mm diameter. Basically, you need to squish about 2 mm of rubber in an area that is about 3 mm thick. There was so much pressure in all directions it actually spread the bracket, which is pretty hefty. This has got to be the wrong part, even though that is what is called out in realoem. As much trouble as it was with a 22.5 mm bar, I couldn't imagine trying to get it to fit on a 23.6 mm bar, which calls for the same bushing.

Has anyone else had this problem? How did you get it to fit?

We ended up getting one to fit, but it was not easy and took forever. Once we got it started, we took another look at realoem and became convinced that they called out the wrong part. We ended up grinding quite a bit of rubber out of the other bushing and it went on fairly well.

It's installed for now, but I'm not completely happy about it. We were able to get plenty of grip on the bar, even on the one we ground down, so it will probably work and not give any problems, but...

I plan on trying to find the real bushing for that bar, but this is what BMW says fits. I'm not convinced.

Anyone have other solutions they tried? Another part that works better? Some inside info on the real part?

[MilehighM3]

That's how the bushings are. I out the E93 23.6mm rear bar in mine and they use the same 2 piece bushing as the 22.5. I used a long set of bolts to get them started, then swapped them once the right ones were able to be threaded in enough to properly to be tightened without damaging. It's not an easy task without different bolts, but they'll be fine.

[Steve_M]

Originally Posted by Bmw135er

That's how the bushings are. I out the E93 23.6mm rear bar in mine and they use the same 2 piece bushing as the 22.5. I used a long set of bolts to get them started, then swapped them once the right ones were able to be threaded in enough to properly to be tightened without damaging. It's not an easy task without different bolts, but they'll be fine.

Well, dang. I guess I need to get another bushing and replace the one I ground down, now.

Longer bolts...that would work. Didn't even think about that.

Thanks!