Uneven brake disc wear

Uneven brake disc wear

Author
Discussion

Mrtank

Original Poster:

28 posts

16 months

Sunday 9th May
quotequote all
Hello everyone, just changed pads o front both sides. It seems that one side is wearing uneven. I've greased the slider pins and cleaned everything. Any idea what the problem might be? It brakes in a straight line no noise etc

fatboy b

9,119 posts

185 months

Sunday 9th May
quotequote all
Always helps to give people a clue on what car.

Mrtank

Original Poster:

28 posts

16 months

Sunday 9th May
quotequote all
Honda civic

HustleRussell

20,056 posts

129 months

Sunday 9th May
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How many miles since changed?

Mrtank

Original Poster:

28 posts

16 months

Sunday 9th May
quotequote all
150 maybe, not sure what went wrong. Thanks for replying

HustleRussell

20,056 posts

129 months

Sunday 9th May
quotequote all
Looks like the pad just hasn’t confirmed to the wear pattern of the disc yet. Have a look after another 150 miles.

E-bmw

6,347 posts

121 months

Monday 10th May
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As above probably just wearing in, but I would be stripping the pad/caliper off the car & checking everything is in right & free.

steveo3002

8,646 posts

143 months

Monday 10th May
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yeah just needs more use to wear the pad into the same profile as the used disc

Evoluzione

6,631 posts

212 months

Monday 10th May
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It's not uncommon these days, even with new pads and discs it does that.
It'll bed in - eventually.

Pastie Bloater

694 posts

132 months

Monday 10th May
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What do the old pads look like?

tapkaJohnD

1,627 posts

173 months

Monday 10th May
quotequote all
The usual "bedding-in" procedure for new pads is not to conform the pads to the worn disc, but to heat them to their maximum operating temp and finally 'cure' them. BUt it might be worthwhile using it here to do the first!

On a suitable stretch of road, brake from progressively higher speeds to a walking pace, until you do so from as fast as the road will allow, preferably as fast as you will ever drive - 70mph? Do not stop, do not keep your foot on the brake for any longer than absolutely necessary, and when done drive home using the brakes as little as possible to allow them to cool.

In this case, then inspect the discs - are the pads bearing across their full perimeter now? If not, then I suggest a more detailed inspection!
John

fatboy b

9,119 posts

185 months

Monday 10th May
quotequote all
tapkaJohnD said:
The usual "bedding-in" procedure for new pads is not to conform the pads to the worn disc, but to heat them to their maximum operating temp and finally 'cure' them. BUt it might be worthwhile using it here to do the first!

On a suitable stretch of road, brake from progressively higher speeds to a walking pace, until you do so from as fast as the road will allow, preferably as fast as you will ever drive - 70mph? Do not stop, do not keep your foot on the brake for any longer than absolutely necessary, and when done drive home using the brakes as little as possible to allow them to cool.

In this case, then inspect the discs - are the pads bearing across their full perimeter now? If not, then I suggest a more detailed inspection!
John
Seems a well-known pad manufacturer has a different opinion.

https://www.ferodo.co.uk/blog/give-brakes-a-break....

Chris32345

1,698 posts

31 months

Tuesday 11th May
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tapkaJohnD said:
The usual "bedding-in" procedure for new pads is not to conform the pads to the worn disc, but to heat them to their maximum operating temp and finally 'cure' them. BUt it might be worthwhile using it here to do the first!

On a suitable stretch of road, brake from progressively higher speeds to a walking pace, until you do so from as fast as the road will allow, preferably as fast as you will ever drive - 70mph? Do not stop, do not keep your foot on the brake for any longer than absolutely necessary, and when done drive home using the brakes as little as possible to allow them to cool.

In this case, then inspect the discs - are the pads bearing across their full perimeter now? If not, then I suggest a more detailed inspection!
John
Bedding is not needed by OEM spec pads that's pretty much only really needed by some more aggressive "race" spec pad

But that being said a few hard application of the breaks shoud help get the pads wearing Better by helping them cut through that bit of rust

rustednut

660 posts

16 months

Tuesday 11th May
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Was it just a brake pad replacement, or pads and discs.

Uneven disc surface to begin with ?

tapkaJohnD

1,627 posts

173 months

Tuesday 11th May
quotequote all
fatboy b said:
Seems a well-known pad manufacturer has a different opinion.

https://www.ferodo.co.uk/blog/give-brakes-a-break....
Whereas I follow Carroll Smith, who knew a thing or two. See "Prevention"
https://www.brakes-shop.com/brakepedia/general/myt...

John

Dave Brand

874 posts

237 months

Wednesday 12th May
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tapkaJohnD said:
The usual "bedding-in" procedure for new pads is not to conform the pads to the worn disc, but to heat them to their maximum operating temp and finally 'cure' them. BUt it might be worthwhile using it here to do the first!
Pads for road use are commonly scorched as a final operation during manufacture to ensure rapid bedding in & eliminate the need to be taken up to high temperatures on the vehicle to optimise performance.

tapkaJohnD

1,627 posts

173 months

Wednesday 12th May
quotequote all
Grabbing the steering wheel and wrenching the thread back on course, why concentrate on a controversy irrelevant to the OP?
The OP wanted a way to get his pads to contact the whole face of the disc. My suggestion was that contrary to usual theory, the traditional 'bedding in' might achieve that, quicker (better?) than waiting hundreds of miles. I still say so, do you say diferent?
JOhn

fatboy b

9,119 posts

185 months

Wednesday 12th May
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I say read the link from Ferodo,

Smint

188 posts

4 months

Monday 17th May
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MrTank, did you 'exercise' the pistons a few times to make sure they are free moving in their bores?, ie by getting an assistant to pump them out gently whilst you watch and push them back?

Ages since i changed Honda pads but do they have those stainless steel sprung clips that the edges of the pad backing plates sit against rather than the pad edge sliding against the caliper itself...if so ping those clips off and give the caliper and clips themselves a good wire brushing, you might find the pad an easier fit once you've done that, get the same issue on Subarus.

I bed pads in exactly as Ferodo suggest in the link, when you fit new pads to an existing disc only a percentage of each pad will be in contact with the disc at first, those contact areas will get really hot if you are hard on them so gently use for a while till they wear in and the whole pad is in full contact the brakes can feel spongy at first for this reason, can take a quite a few miles for bedding in to complete.