BMW 130i warps discs faster than I can change them?!
Discussion
Had it for a good few years now, regular 130i without brembo calipers, brakes were worn when I got it, fitted eicher discs and pads, few weeks later it's shaking like a sh*tting dog when I brake over 60-70 mph.
Replace the bent ones under warranty, twice.
Fair enough, buy nice or buy twice and all that, left them for a bit, replaced them with brembo discs and better pads, these give me about a month or two and then the rear passenger side warps badly, warranty, front right warps.
Figure the issue could be misalignment in the hubs, over time I replace both front hub/bearing assemblies, one of the rear axles and both rear hub flanges. No change, still warping discs.
Totally at a loss, my calipers are in pristine condition and mostly new, I spend most of my life driving up and down the A19, the car doesn't live a hard life, very rare I stand on the brakes or drive particularly fast. All the suspension bushes are fine and tight, alignment is spot on.
I get about 500-1000 miles before a disc warps, I'll replace it, front right and rear left seem the worse having been replaced a few times, front left has warped once, rear right seems to have behaved it's self.
Any ideas??!!
Replace the bent ones under warranty, twice.
Fair enough, buy nice or buy twice and all that, left them for a bit, replaced them with brembo discs and better pads, these give me about a month or two and then the rear passenger side warps badly, warranty, front right warps.
Figure the issue could be misalignment in the hubs, over time I replace both front hub/bearing assemblies, one of the rear axles and both rear hub flanges. No change, still warping discs.
Totally at a loss, my calipers are in pristine condition and mostly new, I spend most of my life driving up and down the A19, the car doesn't live a hard life, very rare I stand on the brakes or drive particularly fast. All the suspension bushes are fine and tight, alignment is spot on.
I get about 500-1000 miles before a disc warps, I'll replace it, front right and rear left seem the worse having been replaced a few times, front left has warped once, rear right seems to have behaved it's self.
Any ideas??!!
It could be due to driving style as well as the mechanical parts.
Do you sit at junctions (or in queues of traffic) with your foot on the brake pedal or use the handbrake? If the former when the brakes are already warm from spirited use then you can create a hot spot on the disc where the pads are clamped, whilst the rest of the disc cools down and causes the warping.
This effect can be amplified if the calliper pistons are sticking and effectively dragging the brakes even when you aren’t applying them. How hot are the discs / wheels when you get out at the end of a journey? If one or more wheel feels hotter (or smells!) more than the others then it could indicate you have a sticking calliper.
Sticking callipers are very common after fitting new discs and pads because the piston has to be pushed right back into the calliper housing and can become jammed due to corrosion or dirt on an area of the outside of the piston that was previously exposed when the brakes were worn.
Chris
Do you sit at junctions (or in queues of traffic) with your foot on the brake pedal or use the handbrake? If the former when the brakes are already warm from spirited use then you can create a hot spot on the disc where the pads are clamped, whilst the rest of the disc cools down and causes the warping.
This effect can be amplified if the calliper pistons are sticking and effectively dragging the brakes even when you aren’t applying them. How hot are the discs / wheels when you get out at the end of a journey? If one or more wheel feels hotter (or smells!) more than the others then it could indicate you have a sticking calliper.
Sticking callipers are very common after fitting new discs and pads because the piston has to be pushed right back into the calliper housing and can become jammed due to corrosion or dirt on an area of the outside of the piston that was previously exposed when the brakes were worn.
Chris
Are they actually warped is the 1st question? Measured? By who? When?
Are you checking the runout on the new ones? Not always necessary I know, but if you are having issues like this it needs to be checked.
Then, bedding in, any ?
And as mentioned driving/braking style can have some effect too.
And as a test have you swapped a "warped"disc from 1 side to the other to see if the problem moves or is no longer apparant?
I think there is an underlying problem that needs to be found first before just keep changing discs and pads. You have probably got a no quibbles part exchange so they are swapping your parts, but it is quite likely it is not the parts at fault.
Are you checking the runout on the new ones? Not always necessary I know, but if you are having issues like this it needs to be checked.
Then, bedding in, any ?
And as mentioned driving/braking style can have some effect too.
And as a test have you swapped a "warped"disc from 1 side to the other to see if the problem moves or is no longer apparant?
I think there is an underlying problem that needs to be found first before just keep changing discs and pads. You have probably got a no quibbles part exchange so they are swapping your parts, but it is quite likely it is not the parts at fault.
Agree with above - your driving, or rather braking style, may be causing this.
It's not so much the hot spot causing actual warping, but the transfer of brake pad material to the rotor surface that can occur if a hot disc and pad are kept in close contact by the brakes at a single spot while stationary. Then, there is more friction in that part of the rotor, and it 'grabs' on each rotation. causing judder on braking.
See: https://www.brakes-shop.com/brakepedia/general/myt... THE WARPED BRAKE DISC AND OTHER MYTHS OF THE BRAKING SYSTEM
And note the author, Carroll Smith, who knew a thing or two about cars.
John
It's not so much the hot spot causing actual warping, but the transfer of brake pad material to the rotor surface that can occur if a hot disc and pad are kept in close contact by the brakes at a single spot while stationary. Then, there is more friction in that part of the rotor, and it 'grabs' on each rotation. causing judder on braking.
See: https://www.brakes-shop.com/brakepedia/general/myt... THE WARPED BRAKE DISC AND OTHER MYTHS OF THE BRAKING SYSTEM
And note the author, Carroll Smith, who knew a thing or two about cars.
John
Coilspring said:
Are they actually warped is the 1st question? Measured? By who? When?
Are you checking the runout on the new ones? Not always necessary I know, but if you are having issues like this it needs to be checked.
Then, bedding in, any ?
And as mentioned driving/braking style can have some effect too.
And as a test have you swapped a "warped"disc from 1 side to the other to see if the problem moves or is no longer apparant?
I think there is an underlying problem that needs to be found first before just keep changing discs and pads. You have probably got a no quibbles part exchange so they are swapping your parts, but it is quite likely it is not the parts at fault.
Exactly...measure to determine exactly what is no longer true. Whether disc, flange, whatever and by how much.Are you checking the runout on the new ones? Not always necessary I know, but if you are having issues like this it needs to be checked.
Then, bedding in, any ?
And as mentioned driving/braking style can have some effect too.
And as a test have you swapped a "warped"disc from 1 side to the other to see if the problem moves or is no longer apparant?
I think there is an underlying problem that needs to be found first before just keep changing discs and pads. You have probably got a no quibbles part exchange so they are swapping your parts, but it is quite likely it is not the parts at fault.
And more often than not with various brake problems...buy OEM. There is no question they are always better quality than those even claiming they're OEM...but not actually OEM.
Firstly, worn castor control bushes (the ones on the lower arms which aren’t in line with the axle) increase a car’s sensitivity to judder, so if your car has done over 100k you might want to change them before you throw effort and money at more brake fixes. I went through 2 sets of discs and rebuilt the calipers on my parents L322 Rangey before I swapped the lower arms and the judder disappeared. I’ve even been involved in road car development projects where bush shore stiffness has been increased to get rid of judder sensitivity
If you’re confident it’s not the bushes then your usage is ideal for creating disc thickness variation if you have excessive disc runout and/or a dragging caliper
Unless you’re an absolute animal on back roads or doing track days and like sitting on the brakes while stationary then it’s unlikely to just be driving style.
Make sure your hubs are cleaned properly and thoroughly with scotchbrite when you’re replacing the discs, any runout when mounted is multiplied out at the rubbing surface
If you’ve done this anyway then replace your caliper sliders and ideally rebuild them completely with fresh seals (and pistons if they’re overly scored or scuffed) while you’re at it.
If you’re confident it’s not the bushes then your usage is ideal for creating disc thickness variation if you have excessive disc runout and/or a dragging caliper
Unless you’re an absolute animal on back roads or doing track days and like sitting on the brakes while stationary then it’s unlikely to just be driving style.
Make sure your hubs are cleaned properly and thoroughly with scotchbrite when you’re replacing the discs, any runout when mounted is multiplied out at the rubbing surface
If you’ve done this anyway then replace your caliper sliders and ideally rebuild them completely with fresh seals (and pistons if they’re overly scored or scuffed) while you’re at it.
Edited by The Wookie on Monday 26th August 23:37
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