Weird brake feel post pad/disc change
Discussion
Recently changed pads and discs on my c6 s6 and having done so the brake pedal feel is a bit different. it seems to take more effort to produce the same level of stopping power and there seems to be less immediate bite. ive torqued up to the right specs and followed the factory procedure down to a t
now the old pads/discs had more than 50% left but not sure why that would make any difference
ive done this a million times on other cars with no issues so wondering what might be at play here
- could there be some air in the system (i did have the brake fluid reservoir cap off to draw off fluid)
- is it that this is how they should normally feel and that previously they felt different due to the wear (i dont think so)
now the old pads/discs had more than 50% left but not sure why that would make any difference
ive done this a million times on other cars with no issues so wondering what might be at play here
- could there be some air in the system (i did have the brake fluid reservoir cap off to draw off fluid)
- is it that this is how they should normally feel and that previously they felt different due to the wear (i dont think so)
Usually as well if you change both disk and pad at the same time they would need less bedding in as they are both pretty flat surfaces already.
My S6 has fairly new disk and pads all round, done by the previous owner last year. It does require quite a lot of force on the pedal to make them work. They do work well but don't feel like they do if you know what I mean.
Might need bleeding, worth a try?
My S6 has fairly new disk and pads all round, done by the previous owner last year. It does require quite a lot of force on the pedal to make them work. They do work well but don't feel like they do if you know what I mean.
Might need bleeding, worth a try?
944fan said:
Usually as well if you change both disk and pad at the same time they would need less bedding in as they are both pretty flat surfaces already.
My S6 has fairly new disk and pads all round, done by the previous owner last year. It does require quite a lot of force on the pedal to make them work. They do work well but don't feel like they do if you know what I mean.
Might need bleeding, worth a try?
you've summed it up perfectly... ill put it down to normal for now thenMy S6 has fairly new disk and pads all round, done by the previous owner last year. It does require quite a lot of force on the pedal to make them work. They do work well but don't feel like they do if you know what I mean.
Might need bleeding, worth a try?
If you're not following a prescribed bedding in process, what you're experiencing is completely normal. Discs and pads need to be bedded it to achieve different things.
Discs need to be bedded in to the pads so that an even, microscopic thick, layer of pad material coats the contact face.
Pads need to be bedded in to de-gas the friction compound and thermo stabilise them. As well as coat the disc face as above.
You can achieve both things using one process. typically pad manufacturers will have a specific bed in process they'll recommend. However, you can do the job using the following method.
1. Take the car out and use normal braking for a period to warm the pads up (so as to not thermally shock them).
2. Once the pads are warm, perform 10 brake applications from 60mph to 5mph at about 90% effort (just before the ABS kicks in is the sweet spot), using normal acceleration between cycles. DO NOT come to a complete stop when doing this. You may start to notice brake fade (reduced stopping power for the effort expended) as you get to cycle 7 or 8, that's completely normal, but bear it in mind for your (and others) safety. You will also notice the smell of the pads again, this is normal. A little smoke is also normal so don't panic.
Once you've completed the 10 applications, drive around normally trying to use the brakes as little as possible, until you're comfortable they're cool enough to park the car up.
I sincerely doubt you have air in the system from just having the cap off the fluid reservoir. You'd notice a spongy peddle if there was air in the system too, not a peddle feel as you're describing.
If you've been using the brakes hard since you've fitted the new discs and pads and not bedded them in correctly, you could have glazed the pads. This would give similar symptoms to those you describe. If you've done this, you'll need to take the pads out and treat the pad surfaces with emery paper to reface them. Then you'll need to bed them and the discs in again.
Paul
Discs need to be bedded in to the pads so that an even, microscopic thick, layer of pad material coats the contact face.
Pads need to be bedded in to de-gas the friction compound and thermo stabilise them. As well as coat the disc face as above.
You can achieve both things using one process. typically pad manufacturers will have a specific bed in process they'll recommend. However, you can do the job using the following method.
1. Take the car out and use normal braking for a period to warm the pads up (so as to not thermally shock them).
2. Once the pads are warm, perform 10 brake applications from 60mph to 5mph at about 90% effort (just before the ABS kicks in is the sweet spot), using normal acceleration between cycles. DO NOT come to a complete stop when doing this. You may start to notice brake fade (reduced stopping power for the effort expended) as you get to cycle 7 or 8, that's completely normal, but bear it in mind for your (and others) safety. You will also notice the smell of the pads again, this is normal. A little smoke is also normal so don't panic.
Once you've completed the 10 applications, drive around normally trying to use the brakes as little as possible, until you're comfortable they're cool enough to park the car up.
I sincerely doubt you have air in the system from just having the cap off the fluid reservoir. You'd notice a spongy peddle if there was air in the system too, not a peddle feel as you're describing.
If you've been using the brakes hard since you've fitted the new discs and pads and not bedded them in correctly, you could have glazed the pads. This would give similar symptoms to those you describe. If you've done this, you'll need to take the pads out and treat the pad surfaces with emery paper to reface them. Then you'll need to bed them and the discs in again.
Paul
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