Okay Maybe RallyCrossing a Lowered Car Was a Bad Idea

I mean, I was just saying how RallyCross is a blast and the M3 was fine after a full day of thrashing in the dirt. Just kidding. It is not fine.

See that? That’s the front control arm bushing bracket, or “lollipop,” if you’re into delicious nicknames. Except this one doesn’t have a congealed mass of Tootsie Roll in the center, just rubber. It holds the rear of the control arm in place, determining camber, caster, and toe. Like, all of the important front suspension geometry measurements.

At some point after the RallyCross in August, I noticed a creaking sound coming from the front right when I would apply the brakes. Some Googling informed me that this was common on BMWs and was due to metal-on-metal contact in the caliper. Cool, no biggie, I’ll get to it when I get to it. Well, two autocross events and a 600 mile round trip to Minnesota later, I got to it. Only to find that the creaking was not the brake caliper, but the FREAKING SUSPENSION MOUNT BEING RIPPED OUT OF THE FRAME RAIL. Okay, cool. I got this. Let’s pull the lollipop off and see what I’m in for.

I decided to pull the insert out of the frame and clean the area up a bit. Except OOPS I JUST KNOCKED THE INSERT INSIDE THE FRAME RAIL. Good thing I have that digital inspection camera.

 

I probably spent a good half an hour fumbling around with the hook, magnet, clothes hanger, and screwdriver trying to fish it out of there. Finally it popped out and I was able to cut out the bent metal and clean up the surrounding area.

After some CAD (cardboard-aided design), I cut out some 3/16″ plate to fit the new hole.

Next up was cutting out the oval. Fortunately my little 110V plasma can pierce 3/16″.

Lots of test fitting. Measure 14 times, cut 13 times, I always say.

I put the insert in place using the remnants of the frame rails to position it. I also measured depth based on the other side. It’s…close?

With the bracket tacked, I was able to fully weld the insert to the plate on both sides.

Then I fully welded the plate in place.

It was then primed and undercoated.

So what have we learned? As usual, nothing. This car will most certainly see dirt again. The funny thing is that the two autocrosses I ran with it broken were my best finishes to date. So I guess I learned that suspension geometry doesn’t matter? Or maybe that variable suspension geometry is better? Who knows. But while I’m under here and the welder’s already warmed up…