e46 braking issues
Discussion
After getting my e46 brake judder issues fixed last summer with some new front pads/discs and a new caliper...
Recently parked it up for a couple of weeks as the MOT expired and I was waiting for a new windscreen. Discs showed some rust in that time but not much I could do (had unfortunately driven on some very salty roads).
Discs cleared up a bit on the way to the MOT, but still look patchy with the rust not totally cleared up in some places. Passed with no issues, but a lot of judder/wobble through the steering wheel.
A couple of days later I get a pad wear light up on the dash
Loads of meat on the front pads, rears look low but hardly down to the backing.
What to do next? Use a on-car disc skimming service (guessing will cost £200 ish), new rear pads (can I use the fronts or are they scrap now)?
Or admit defeat and buy all new discs/pads? Guess that will be £500 for genuine stuff...
Really pissed off as it's expense I could have done without and it shouldn't have been necessary... Don't understand why the pads didn't clean the rust off, there was no problem before...
Recently parked it up for a couple of weeks as the MOT expired and I was waiting for a new windscreen. Discs showed some rust in that time but not much I could do (had unfortunately driven on some very salty roads).
Discs cleared up a bit on the way to the MOT, but still look patchy with the rust not totally cleared up in some places. Passed with no issues, but a lot of judder/wobble through the steering wheel.
A couple of days later I get a pad wear light up on the dash
Loads of meat on the front pads, rears look low but hardly down to the backing.What to do next? Use a on-car disc skimming service (guessing will cost £200 ish), new rear pads (can I use the fronts or are they scrap now)?
Or admit defeat and buy all new discs/pads? Guess that will be £500 for genuine stuff...
Really pissed off as it's expense I could have done without and it shouldn't have been necessary... Don't understand why the pads didn't clean the rust off, there was no problem before...
Some interesting information in general here: https://alconkits.com/technical-info/brake-tech/56...
HTH
HTH
Could just be spots of surface corrosion that are not being braked off with enough heavy braking - it's not just salt that causes this, even normal rain, washing or tyre/wheel cleaning products will do the same.
Mine do it within about a week, and it takes about 50 miles to clean them up again - although only the parts the pads touch...the bit between the bell & the inner disc stays rusty as the pad doesn't sweep it.
Could also be areas of pad transfer - as the BMW pads are quite soft.
How many miles since you had all new discs & pads - my CSL-size discs last about 30,000 miles and pads (including track days) about 5,000.
Mine do it within about a week, and it takes about 50 miles to clean them up again - although only the parts the pads touch...the bit between the bell & the inner disc stays rusty as the pad doesn't sweep it.
Could also be areas of pad transfer - as the BMW pads are quite soft.
How many miles since you had all new discs & pads - my CSL-size discs last about 30,000 miles and pads (including track days) about 5,000.
It does appear there is an issue with a lot of cars with modern, reasonably soft, pads.
On the front of a well used car you dont see it, but on rears, and infrequently used cars stored outside, you get into a mess where the disk rusts and then isnt fully cleaned back by the pads, and the rust again, till you get to a situation where the rough rusted disk appears to wear the pad away, rather than the pad buffing the disk back up again.
The rears on my E46 330ci are working on half the available surface, I cant get i to clean up for all the heavy driving and hard braking in the world, even trailing the brakes. The MOT doesnt appear to have an issue with it, but its not nice to look at.
If it where on the front I expect you would feel it as brake judder.
I am sure disk can warp, but I have also heard people say that you can typically cure it by putting them in a domestic oven at 280C for an hour. And that certainly you should do this before re-skimming them cold, else they will just change again when next hot.
Daniel
On the front of a well used car you dont see it, but on rears, and infrequently used cars stored outside, you get into a mess where the disk rusts and then isnt fully cleaned back by the pads, and the rust again, till you get to a situation where the rough rusted disk appears to wear the pad away, rather than the pad buffing the disk back up again.
The rears on my E46 330ci are working on half the available surface, I cant get i to clean up for all the heavy driving and hard braking in the world, even trailing the brakes. The MOT doesnt appear to have an issue with it, but its not nice to look at.
If it where on the front I expect you would feel it as brake judder.
I am sure disk can warp, but I have also heard people say that you can typically cure it by putting them in a domestic oven at 280C for an hour. And that certainly you should do this before re-skimming them cold, else they will just change again when next hot.
Daniel
Brake discs can warp...yes.
It's just that in 99% of the cases where people insist they've got warped discs, it is nothing of the sort and they're riding the brake pedal, or they've put sport pads in and drive like they've got Miss Daisy in the back.
I've had fully floating discs rumble and shake like mad after a few laps on a track day (strangely only when wet though) and the passenger at the time said I'd warped them. Did the rest of the day driving as hard as usual, and there was still the shaking for about 50 miles, until normal use had smoothed the pad deposits off again and by the time I was home an hour later there was no sign of vibration.
I did that again and again over 6 or 7 track days - and the drive home, or the weekly commute the following week would clear it all up.
It's just that in 99% of the cases where people insist they've got warped discs, it is nothing of the sort and they're riding the brake pedal, or they've put sport pads in and drive like they've got Miss Daisy in the back.
I've had fully floating discs rumble and shake like mad after a few laps on a track day (strangely only when wet though) and the passenger at the time said I'd warped them. Did the rest of the day driving as hard as usual, and there was still the shaking for about 50 miles, until normal use had smoothed the pad deposits off again and by the time I was home an hour later there was no sign of vibration.
I did that again and again over 6 or 7 track days - and the drive home, or the weekly commute the following week would clear it all up.
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