Brake Pull

[SharpAndCunning]

Looking for some ideas. 2014 BMW x1 35i, 80,000miles


Brakes seem to be acting up, if I hit the brakes when they are cold or haven't been applied the car seems to pull a bit to left. It's usually only noticeable with 1 hand on the wheel.

Easy solution, right? So I bled all the brakes, but the bleeder screw broke off in the passenger front caliper. I tried a reman caliper and it was junk, so I bought a Powerstop L3334. The fit and finish was a lot better, but as it should be, the L3334 is a new caliper.

Same phenomenon. Arguable worse. Can't seem to bleed the new caliper enough to get brake engagement towards the top of the pedal. From a bleeding perspective the air is out.

But shouldn't it pull to the right with the new caliper, being it's got less drag and should function better?
*
I did use an infrared gun and both rotors and calipers are within 5*F of each other after normal driving and spirited breaking.

[wheela]

How do your thrust bushings look? I had that problem, and turned out one thrust bushing was shot. I had them both replaced and problem was solved.

[dave14x28]

I second the comment about thrust bushings. I just replaced my thrust arms for the second time, at 134k. First time was at 86k by an indy shop doing my timing chain, and they looked REAL bad (see photo) but all I recall was that at the time the car seemed a little directionally unstable in a crosswind.

This time around, I began noticing a slight pulling to one side or the other under braking. After seeing the YouTube vids of the front wheels toeing out severely as the vehicle comes to a stop on the shop floor, I mounted a camera to my fender and did a few accel/decel tests and sure enough, the toe changes were not as bad but still clearly visible. All I could see on the bushings this time was very slight cracking, but the pulling was real.

I saw someone post that 30-40k is all you should expect to get out of a set of thrust arm bushings, so this time I elected to try the Turner Motorsport monoball thrust arms. I also did the wishbones and the tie rods at the same time, leaving only the struts as original. Definitely a little more NVH from the monoballs, but only annoying on very sharp bumps - most of the time the noise is not much different than stock.

[SharpAndCunning]

Originally Posted by dave14x28

I second the comment about thrust bushings. I just replaced my thrust arms for the second time, at 134k. First time was at 86k by an indy shop doing my timing chain, and they looked REAL bad (see photo) but all I recall was that at the time the car seemed a little directionally unstable in a crosswind.

This time around, I began noticing a slight pulling to one side or the other under braking. After seeing the YouTube vids of the front wheels toeing out severely as the vehicle comes to a stop on the shop floor, I mounted a camera to my fender and did a few accel/decel tests and sure enough, the toe changes were not as bad but still clearly visible. All I could see on the bushings this time was very slight cracking, but the pulling was real.

I saw someone post that 30-40k is all you should expect to get out of a set of thrust arm bushings, so this time I elected to try the Turner Motorsport monoball thrust arms. I also did the wishbones and the tie rods at the same time, leaving only the struts as original. Definitely a little more NVH from the monoballs, but only annoying on very sharp bumps - most of the time the noise is not much different than stock.

I don't see anything bad, they look okay. I'm guessing a pry bar side to side would be a good test to see if they are bad?

Did you mount a go pro on each side? I like this idea, as my issue is only at speeds say, above 40/45mph.

The weird part for me, is if I just gently touch the brakes, then hit them harder it doesn't happen. That is what is leading me to think that one caliper is "slow" to engage, but the car seems to pull to the right, and the right front is new (broken bleeder screw, did it with the old caliper too) and I think, I rebuilt the right rear last year because it was sticking. So I'm guessing the left rear might not be engaging as it's supposed to and the car tracks right until it does.