[Fundguy1]

So I've never experienced this before. I have 221,000 miles now so the list of suspects is long. It feels like rotors are warped, but the brake rotors and pads are new and..... it happens only sometimes. Other times they're smooth like they should be.

I have new rotors and pads from stop tech. Thought it might be a bad bushing. I upgraded the front control arms to new M3 arms and one of the bushings was blown. I thought great. Problem solved. Nope. Still present.

Could the pads be bad possibly? Something loose? Different bushing? Looking for possible culprits to check.

I don't think it's rotors. They don't warp then unwarp. I also don't think it's rims or tire for the same reasons. They're Beyron with Michelin PSS. I redid the coil overs with new KWV2 after this started happening and no change.
Thx

[Fundguy1]

Nobody?

[feuer]

Uneven brake pad deposit?

[Fundguy1]

Originally Posted by feuer

Uneven brake pad deposit?

What's a fix for that? I was thinking maybe the pads are the wrong rating for me, mostly daily driving, and could be leaving deposits on the rotors. Or the breaking didn't take. I'm also thinking of swapping to a ceramic.

[feuer]

Originally Posted by Fundguy1

What's a fix for that? I was thinking maybe the pads are the wrong rating for me, mostly daily driving, and could be leaving deposits on the rotors. Or the breaking didn't take. I'm also thinking of swapping to a ceramic.

Flex-hone

[Needbmwpartzz]

I have found weather or temperature variance does this but your case could be many issues..eg....worn wheel bearing or even bushings gone or struts worn can imitate the type of intermittent issue you have described because when the brakes are applied these worn components present themselves the same as a warped rotor so check for the obvious.
A shop can easily detect axial or lateral run out on a rotor with a dial-guage micrometer and also the other issues that mimic this.

[Fundguy1]

Front control arms and struts are new. Just had then installed. Problem was before they were installed. I'll have the brakes looked at by a shop. Any other bushings?

Weather and temp aren't a factor. I'm in Florida. It's consistent.

[Fundguy1]

Still trying to figure it out.
Problem is intermittent. More bad than good unfortunately.
New rotors and pads. If it was every brake I would say these.
Doesn't happen without braking. Probably not wheels or tires.
Replaced front control arms. They cone with bushings installed. Oem M3.

Any other ideas?

[justpete]

Originally Posted by Fundguy1

Still trying to figure it out.
Problem is intermittent. More bad than good unfortunately.
New rotors and pads. If it was every brake I would say these.
Doesn't happen without braking. Probably not wheels or tires.
Replaced front control arms. They cone with bushings installed. Oem M3.

Any other ideas?

Rotors not seated correctly, lock screw backed out, wheel improperly torqued (unevenly), pads not beveled (probably not needed), guide rods worn, bushings at end of lifte?

[Fundguy1]

I'll check guide rids. Brakes were professionally installed so I'm guessing they're torqued correctly. It is intermittent so i would think if there was a rotor problem it would be constant and occur each time i brake. Which bushings should I check besides strut/coil over and front control arm? Those are new. Thx

[justpete]

Originally Posted by Fundguy1

I'll check guide rids. Brakes were professionally installed so I'm guessing they're torqued correctly. It is intermittent so i would think if there was a rotor problem it would be constant. Which bushings should I check besides strut/coil over and front control arm? Those are new. Thx

Might've handed it off to a lesser tech who mucked up the torque.

Was thinking the guide bushings might be shot or lubed when they shouldn't be, maybe causing the pads to catch a bit.

[Fundguy1]

I'll check them myself. What's the final torque? 90? And caliper bolt torque?

[justpete]

Originally Posted by Fundguy1

I'll check them myself. What's the final torque? 90? And caliper bolt torque?

rotor bolt - 12 ft-lb

front pad carrier to knuckle - 81 ft-lb

brake caliper to pad carrier - 22+/-1 ft-lb

rear pad carrier to bearing carrier - 48 ft-lb (says 50 on previous page)

wheel to hub - 88.5 ft-lb (assuming stock bolts)

Per Bentley

[Fundguy1]

Thx muchacho

[justpete]

Originally Posted by Fundguy1

Thx muchacho

de nada

[335D Alpha Pappa]

Originally Posted by Fundguy1

I'll check guide rids. Brakes were professionally installed so I'm guessing they're torqued correctly. It is intermittent so i would think if there was a rotor problem it would be constant and occur each time i brake. Which bushings should I check besides strut/coil over and front control arm? Those are new. Thx

I would not assume that about the torque. I have the same problem with brake judder.

So while I am waiting for the new rotors and pads to show up, I decided to pull the tires and scuff the rotors to see if there was uneven pad buildup causing the shudder. I had the fronts replaces last year by the dealership under warranty for the same problem.

I could not break free a couple of lug bolts with my 300# impact gun. I had to get a breaker bar and really wrench on it. Looks like the dealer tech used his impact gun to really tighten the bolts. Also had a bitch of a time getting the tire off. Tech didn't use anti-seize between the rotor and wheel.

Put the fronts back on and torqued it to 88lb-ft. Should probably break the rears free and re-torque them to the correct torque.

[asrautox]

Originally Posted by Fundguy1

Replaced front control arms. They cone with bushings installed. Oem M3.

Any other ideas?

Upper, Lower, or both? My research says it's the upper control (thrust) arm that causes this issue.

[Fundguy1]

Both unfortunately. One had a blown bushing too but it still does it.

[gabbo241]

Hi everyone,

I have a 2009 328i sport package (78k miles) with similar brake judder issues. Front pads and rotors have been replaced three times now and the issue occurs the same way every time:

1. For the first few weeks and couple of hundred miles, brake judder seems gone

2. After a couple of hundred miles the brake judder reappears when braking, first when braking lightly or moderately at 60-80 mph.

3. The judder gets progressively worse - manifests as an oscillation in the steering wheel under braking.

4. Each time, the dealer diagnoses "warped rotors" and replaces the rotors and pads. Repeat process.

5. They have inspected the calipers, suspension bushings, suspension components and find that all of that checks out.

6. I've had the front wheels recently re-rounded and balanced since they were slightly bent from pothole impacts.

From what I've read, "warped rotors" really means "uneven pad deposits" - but what could be causing this uneven pad deposit??

The issue only manifests itself under braking.

Any ideas are greatly appreciated - the dealership techs can't seem to really diagnose the problem here.

[Fundguy1]

I never had one brake issues. I've had 3 oem rotor and 6 oem pad sets. If the torquing doesn't work I'm going to try a new set of pads. Probably cool carbon or akebono ceramic.

[Fundguy1]

Gonna try torquing today.

[feuer]

Let us know but I'm very skeptical that re-torque will fix it.