Help! Why do my rotors keep warping?
#1
Help! Why do my rotors keep warping?
2003 Base model, 204K miles (yes, 204K - not a typo).
In the past 2 years, I've gone through 4 sets of rotors. I use stock Mini pads.
It's always the same. The new rotors feel great for a few weeks, then slowly I start to feel the vibration only while braking, until it gets so bad I have to bring it to my mechanic and he puts on another set.
With the last set, he also replaced the bushings and rods (I think - I don't know much about those). He hoped that would do it, but now I'm feeling the vibration again after a month or so.
I never had this problem in the 7 years previous to the last 2 years. I'm not an aggressive driver, and don't use my brakes all that much (mostly highway driving).
Any ideas I could pass on to my mechanic for him to look for?
In the past 2 years, I've gone through 4 sets of rotors. I use stock Mini pads.
It's always the same. The new rotors feel great for a few weeks, then slowly I start to feel the vibration only while braking, until it gets so bad I have to bring it to my mechanic and he puts on another set.
With the last set, he also replaced the bushings and rods (I think - I don't know much about those). He hoped that would do it, but now I'm feeling the vibration again after a month or so.
I never had this problem in the 7 years previous to the last 2 years. I'm not an aggressive driver, and don't use my brakes all that much (mostly highway driving).
Any ideas I could pass on to my mechanic for him to look for?
#3
B. Unlikely that my brakes get that hot since I do not use them aggressively. And even more unlikely that it would happen 4 different times.
#4
I don't know what the problem is, but I don't think you're warping the rotors.
Vibration can occur due to the uneven transfer of brake pad material to the rotors. Thus, it could be that you're not breaking-in the pads to the rotors (bedding or burnishing) quite right. It could be that your braking is actually TOO gentle rather than not gentle enough. Maybe if you have the rotors cleaned off with a cleaning solution you can re-bed the brakes.
Vibration can occur due to the uneven transfer of brake pad material to the rotors. Thus, it could be that you're not breaking-in the pads to the rotors (bedding or burnishing) quite right. It could be that your braking is actually TOO gentle rather than not gentle enough. Maybe if you have the rotors cleaned off with a cleaning solution you can re-bed the brakes.
#5
OVERDRIVE
iTrader: (1)
Typically this is caused by the brake pads dragging. A dragging pad causes the rotor to over heat. When you stop and park the car, the part of the rotor away from the pad cools more quickly causing the rotor to warp.
There are some other threads about the pads not being put in correctly on the Gen 1s and the pads dragging. The other possibility is that the piston is sticking. You said your mechanic replaced the slides, but it seems that you are not sure. These if bent, old, rusty, dirty, etc can also cause the outside pad to drag. You might want to check for sure.
Is there a chance that you rests your foot on the brake pedal? Some people have been known to and didn't realize it would cause the pads to drag also.
Do you know if both rotors are warped? Or just one and your mechanic is replacing both? If both rotors are warped, then I wonder if something in the master cylinder vacuum booster is leaking or miss-adjusted and causing it to apply the brakes just a little bit which is overheating the rotors...Just a thought.
There are some other threads about the pads not being put in correctly on the Gen 1s and the pads dragging. The other possibility is that the piston is sticking. You said your mechanic replaced the slides, but it seems that you are not sure. These if bent, old, rusty, dirty, etc can also cause the outside pad to drag. You might want to check for sure.
Is there a chance that you rests your foot on the brake pedal? Some people have been known to and didn't realize it would cause the pads to drag also.
Do you know if both rotors are warped? Or just one and your mechanic is replacing both? If both rotors are warped, then I wonder if something in the master cylinder vacuum booster is leaking or miss-adjusted and causing it to apply the brakes just a little bit which is overheating the rotors...Just a thought.
#6
Do you know if both rotors are warped? Or just one and your mechanic is replacing both? If both rotors are warped, then I wonder if something in the master cylinder vacuum booster is leaking or miss-adjusted and causing it to apply the brakes just a little bit which is overheating the rotors...Just a thought.
Thank you all for your thoughts.
#7
You might also ask your mechanic about brake judder, which is just what you described; moderate to extreme vibrations under braking. I don't know much about it, but it's supposed to be caused by "hot spots" on the rotors; localized high thermal areas on the rotors that render the outside edges wavy or uneven, thus producing a vibration. Any unevenness around the surface of the rotor can be a source of vibration.
Why your new rotors and pads keep developing the same vibration pattern is the bigger mystery.
Why your new rotors and pads keep developing the same vibration pattern is the bigger mystery.
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#10
He specializes in BMWs and Minis, and seems to know his stuff.
#11
I'd suspect dragging rotors. Used to warp them on my CRX often for whatever reason.
Given that you're warping them in that short a time, did you just replace them or have them turned?
I'd have them check the runout and find out if they are all warping, or if it's just front (likely) or possibly just one rotor. The pedal feel would likely be the same.
Given that you're warping them in that short a time, did you just replace them or have them turned?
I'd have them check the runout and find out if they are all warping, or if it's just front (likely) or possibly just one rotor. The pedal feel would likely be the same.
#12
#13
#14
You should be able to check for dragging by lifting the MINI, and spinning the wheels....
#15
Driving style....
Cold brakes...you use them on the highway...then they are cold to hot instantly ....then maybe a splash of water...or a stop at a bottom of a ramp with the pads against the rotors....all the hardesr things you can do on a set.
Strange how minior differences in driving style can cause differences in rotor life from person to person....short of trying a different brand next time, not sure what else you can do.
Cold brakes...you use them on the highway...then they are cold to hot instantly ....then maybe a splash of water...or a stop at a bottom of a ramp with the pads against the rotors....all the hardesr things you can do on a set.
Strange how minior differences in driving style can cause differences in rotor life from person to person....short of trying a different brand next time, not sure what else you can do.
#16
Scooter, I would prob try something else besides "genuine" BMW pads. They suck. Mine were grabby, diffilcult to modulate smoothly and dusted like nobody's business. The BMW forums are covered w/ negative comments from the 1 to the 7 series, so nobodys exempt, and few mechanics I talked to give 'em the time of day. Replace w/ a good set of ceramo-metallics and see what happens, I think its what Jim said, material transfer. Surface cut the rotors lightly to clean them off then change pads. There is no good reason you should have to live w/ this nonsense.
#17
I'd suspect dragging rotors. Used to warp them on my CRX often for whatever reason.
Given that you're warping them in that short a time, did you just replace them or have them turned?
I'd have them check the runout and find out if they are all warping, or if it's just front (likely) or possibly just one rotor. The pedal feel would likely be the same.
Given that you're warping them in that short a time, did you just replace them or have them turned?
I'd have them check the runout and find out if they are all warping, or if it's just front (likely) or possibly just one rotor. The pedal feel would likely be the same.
As far as driving habits, I never had this problem in the first 180K miles or so - only in the last 25K. If it was the way I drove the car, this problem would have shown up earlier.
#18
OVERDRIVE
iTrader: (1)
How many miles on the car?
As for the MINI parts being "crap", having had 3 MINIs I have found little reason to fault their parts and I have run into plenty of after market crap. So if you like their parts, stick with them.
I would be for checking if the pads are dragging. Drive the car a bit in stop an go traffic then jack the car up while things are still warm, spin the wheel and see if you hear or feelit dragging.
As for the MINI parts being "crap", having had 3 MINIs I have found little reason to fault their parts and I have run into plenty of after market crap. So if you like their parts, stick with them.
I would be for checking if the pads are dragging. Drive the car a bit in stop an go traffic then jack the car up while things are still warm, spin the wheel and see if you hear or feelit dragging.
#20
#21
Brake discs can reach temperatures of up to 800 to 1000 degrees. Hit a piece of metal at that temperature with cold water, I guarantee it won't cool at a uniform rate and will warp. Just wait your turn.
#23
I've committed worse crimes than that.
#24
from my old computer programming days:
when you are sure everything is right
and the program still doesn't work
something you are sure of
is wrong
in this case if your mech keeps changing the same things and the problem keeps coming back I'd suspect he's not looking in the right place. Hanging caliber or piston . . .
But if I have to make suggestions to my mech as to where to look, I don't ... I find a new mech! It gets expensive to play 'try this' on a car .. any car.
p.s. I'd REALLY look at different pads if I were you, if for no other reason than DUST. EBC Green perform IMO nearly the same as OEM and the dust is 1/3 of what I see from OEM (I used green on my 02 and on my 07 until recently); EBC reds, which I just recently put on are lower dust yet, but ARE causing me to re-learn brake application in my 07S. They grab earlier and faster . . . did not say this was bad ... different.
when you are sure everything is right
and the program still doesn't work
something you are sure of
is wrong
in this case if your mech keeps changing the same things and the problem keeps coming back I'd suspect he's not looking in the right place. Hanging caliber or piston . . .
But if I have to make suggestions to my mech as to where to look, I don't ... I find a new mech! It gets expensive to play 'try this' on a car .. any car.
p.s. I'd REALLY look at different pads if I were you, if for no other reason than DUST. EBC Green perform IMO nearly the same as OEM and the dust is 1/3 of what I see from OEM (I used green on my 02 and on my 07 until recently); EBC reds, which I just recently put on are lower dust yet, but ARE causing me to re-learn brake application in my 07S. They grab earlier and faster . . . did not say this was bad ... different.
#25
He always replaced them - never turned them. It was always just the fronts. I feel it much more in the steering wheel than in the pedal.
As far as driving habits, I never had this problem in the first 180K miles or so - only in the last 25K. If it was the way I drove the car, this problem would have shown up earlier.
As far as driving habits, I never had this problem in the first 180K miles or so - only in the last 25K. If it was the way I drove the car, this problem would have shown up earlier.
While it's not a solution, if it's recurring, I'd definitely turn them rather than replace. If nothing else, just to see if the reduced rotor mass results in the condition returning more quickly or not. All information is valuable.