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-   -   What could be causing this uneven brake wear? (http://forum.e46fanatics.com/showthread.php?t=934562)

Westrace 07-22-2012 12:44 PM

What could be causing this uneven brake wear?
 
I recently had my tires changed to 245f/275r about three weeks ago, but I don't remember if this problem started before or only after the tire change. The left front brake disc seems to show quite a bit of uneven wear. There is no vibration on the highway when just driving, but when I sort of put my foot on the brake pedal, I do feel some mild vibration.
Only the left front brake disc shows uneven wear but the other three are fine.

Do you think there could be something with the tires? Or could be something else?

Pic of left front brake disc. The inner part sees fine but the outer part shows these lines wear.
http://i47.photobucket.com/albums/f1...v/IMG_0237.jpg

Pic of right front brake disc, no such problem:
http://i47.photobucket.com/albums/f1...v/IMG_0239.jpg

sakumaxp 07-22-2012 01:26 PM

im no brake expert, but i doubt tires would cause uneven wear on the rotors. try changing all 4 along with pads and see if the problem persists.

$ilent ///M 07-22-2012 02:41 PM

may need caliper rebuild kit and/or brake bleed. the square seal that help retract the pads from the rotor may be worn causing the brakes to ride. also lube the guide pins

bwallace530 07-22-2012 02:45 PM

I have seen it from bad calipers.

They can be chipped have a chunk taken out.

The calipers are actually pretty soft material.

When did you change the pads they look like they are bad. Maybe got some rocks in there and they groved the pad.

Your best bet it go to les scwab get a free estimate or take them off and see what the problem is.

But you need too do a full brake Job now just replacing that side will be pointless, you can get all brakes and pads for around 230 for drilled and slotted.

tsimurph 07-22-2012 03:37 PM

Unlikely the tire change has anything to do with your brake issue.
There could be several thing going on:
1. Cracked pad. 2. Caliper hanging up (not completely releasing) 3. Bent guide pin allowing the caliper to become unsquare with the rotor. 4. Sticky guide pins keeping the caliper from sliding freely 5. Some debris caught between the caliper and the rotor.
You need to disassemble that side and investigate further.

abakos 07-22-2012 04:55 PM

Something weird is going on...that is to say, that's not normal.

I've seen all kinds of weird things happen, including cross-threaded caliper pins, rust on carrier so pads don't slide, and sticky calipers. I'd do a teardown and see if the pins and pads are sliding okay, and then also see if the piston is hanging up badly. If the piston is hanging up, then just get some new ones from bimmerworld along with a rebuild kit.

Either way, you're going to need a new rotor.

Westrace 07-22-2012 07:59 PM

Do you guys thing the guy who did the tire job may have done something that could have damaged either the brake caliper or something to the brake pads?
Also is it possible to resurface the rotor?

tsimurph 07-23-2012 12:05 PM

Not during the normal course of changing a tire, but who knows what they really did.... If you are going to return to the tire place to tell them you think that they did it you will have a slim chance of proving it; but I guess it is worth a try.
Don't be cheap in attempting to cut the rotor as BMW doesn't sanction it and that one looks like you would have to remove a lot of metal to get it flat. Buy a new one. The other side looks reasonably new so even though I don't reccommend it you might get away with just changing the one side. Usually they are changed in pairs per axle.

DSilk56 07-23-2012 12:10 PM

Tire shops have an extremely annoying habit of over-torquing wheel bolts when they put the wheels back on your car. They use a compressor-driven socket that puts the bolts on WAY too tight, and this can warp your rotors. If you cannot remove the bolts using a simple spanner, without the need to jump on it or use a mallet, they are on too tight.

tmiked 07-25-2012 07:17 AM

Stuck caliper.
Remove & rebuild

Westrace 07-25-2012 11:48 AM

Quote:

Originally Posted by tmiked (Post 14600167)
Stuck caliper.
Remove & rebuild

When at speed, if I just slightly tap on the brake pedal, I do feel a pulsating stream on the brake pedal and on the steering wheel as well, but I wouldn't characterize it as vibration since that may be too strong. If I do stomp on it and brake hard, I don't really feel any vibration and it feels pretty solid and if there's any vibration , it's probably from the road surface. I think I can tell the difference if it comes from the rotor or the road because the rotor will give a more periodic vibration.

My guess is the brake pads are riding on the rotor which is causing the uneven line. This morning when I looked at the rotor surface closely, I saw a couple of pretty sharp cuts on the surface.

If the rotor is warped, then braking hard would feel the vibration the most I think but it doesn't seem to be the case. The car has about 100K miles so I am not sure if the previous owner ever did any maintenance on the brake calipers.

bwallace530 07-25-2012 11:11 PM

You need to take it apart and see im surprised your still driving it and have not even seen a shop or checked it out your self.

Every single person here is guessing until you take the wheel and caliper off.

Westrace 07-26-2012 03:04 PM

Quote:

Originally Posted by bwallace530 (Post 14602784)
You need to take it apart and see im surprised your still driving it and have not even seen a shop or checked it out your self.

Every single person here is guessing until you take the wheel and caliper off.

Will soon but most likely at a shop. August is a three pay check month so the timing is very good. :thumbup:
and "Draghi just put a floor on the market". :-)
Also I have a set of springs and shocks so I plan to do them all at the same time.

But thanks for all the responses.

Westrace 08-28-2012 09:47 PM

I sure feel like an idiot. The problem was simple as re-torquing the bolts. All I did was loosen the bolts a bit, and re-torque at 88lbs-ft. I did this on Sunday and after driving for awhile, I didn't feel any vibration. I wasn't quite sure but after driving for two more days, I am pretty sure the vibration has gone away.

I mean these people are paid but if they can't get something as basic as torquing, I don't know what to say.

tsimurph 08-29-2012 05:05 AM

Glad you found the problem. It is becoming harder and harder to find anyone trustworthy to work on your car anymore.....

Beamer Creamer 09-27-2012 03:38 AM

Machine or looks like replace rotors on both fronts. Inspect caliper slides and if piston seizing? Slides must have worked to get it to wear on the outside of rotor but rocks dont make that many grooves? New pads of course after rotor swap. Push piston into caliper till flush then watch as brake is stepped on. Not from tires for sure. Clean and antiseize slides.

roadtrip1098 09-27-2012 09:13 AM

Sounds like a warped rotor. I'd recommend replacing them. I have to do the same on mine when I tear it down for the Winter. Not a bad idea to check wheel bearings while you're at it.

BWOODM3 09-27-2012 10:06 AM

So your problem was the lug bolts needed to be torqued to spec? Wow, didn't think over tightened lug bolts would cause that. I can't stand it when shops allow their employees to tighten lug nuts/bolts with air. Last couple times I've had a shop take off my wheels, I made sure to stand in and watch to make sure their using torque wrenches and anti seize to put the wheels back on.

Westrace 09-28-2012 12:06 AM

Quote:

Originally Posted by BWOODM3 (Post 14767193)
So your problem was the lug bolts needed to be torqued to spec? Wow, didn't think over tightened lug bolts would cause that. I can't stand it when shops allow their employees to tighten lug nuts/bolts with air. Last couple times I've had a shop take off my wheels, I made sure to stand in and watch to make sure their using torque wrenches and anti seize to put the wheels back on.

I think the M3 rotors are probably lighter, thinner, and maybe a bit softer and are designed for performance and light weight so they are probably more sensitive to over-torqued. I never had this issue before on any of my previous "low end" cars.

Alan 09-28-2012 08:01 AM

Quote:

Originally Posted by BWOODM3 (Post 14767193)
So your problem was the lug bolts needed to be torqued to spec? Wow, didn't think over tightened lug bolts would cause that. I can't stand it when shops allow their employees to tighten lug nuts/bolts with air. Last couple times I've had a shop take off my wheels, I made sure to stand in and watch to make sure their using torque wrenches and anti seize to put the wheels back on.



What are they doing with the anti-seize?


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