Brakes a bit graunchy/lurchy just as you stop.

Brakes a bit graunchy/lurchy just as you stop.

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Discussion

Ken Figenus

Original Poster:

5,706 posts

117 months

Tuesday 2nd December 2014
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There is a little audible groan and a small lurch as I feather off the brakes and come to a gentle stop - ruins the smooth effect! Does anyone know how what causes it? Plenty of meat on the pads. 20k miles - disks like new.

Cheers
KF

Locknut

653 posts

137 months

Wednesday 3rd December 2014
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20k miles, is that on the pads or the car or both? In other words, are these the original pads or replacements?

Ken Figenus

Original Poster:

5,706 posts

117 months

Wednesday 3rd December 2014
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Originals I would have thought - no one has needed to swop disks on a this car yet due to wear according to dealer.

The Wookie

13,946 posts

228 months

Tuesday 9th December 2014
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That sort of light braking at low speed can polish up the discs and pads quite a bit and cause low friction, which then can cause all sorts of NVH issues, usually squeal, under whatever conditions are the trigger for that particular vehicle. Could be the cold weather in this case.

Try giving the brakes a good pasting and see if it disappears.

Also might be worth checking that everything is as it should be around the brakes, for example pad sticky backings have been unpeeled so the pads stick to the pistons, pistons move freely, sliders move freely, everything is torqued up to the right spec, disc and wheel mounting faces are clean and free of any debris.

Next option is that the pads are worn and have deteriorated, introducing the issue or the wear has removed any edge chamfers they had. If the pads are supposed to be chamfered then chances are the chamfer was added to cure an issue, perhaps even the issue you have.

The final alternative is that something in the suspension has gone out of spec and has introduced a sensitivity, probably the bushes!

Edited by The Wookie on Tuesday 9th December 08:49

Ken Figenus

Original Poster:

5,706 posts

117 months

Tuesday 9th December 2014
quotequote all
Thanks Wookie - sounds like a little root around over the Xmas break (ha!) is in order. I am quite a light braker (17mpg makes you tight!) and there is a lot of engine braking on offer so I think Plan A (a quick 'amble') sounds good as a first try. Remember having to do that with a Scooby on some temporary harsh pads once and it did fix the issue. Thanks for the advice. KF

The Wookie

13,946 posts

228 months

Tuesday 9th December 2014
quotequote all
No worries, keep us updated!

This sort of thing is often brought about by a fluke of driving style.

We had a customer complaint about a squeal on a particular type of vehicle. I had driven our one for thousands of miles of varied driving, and in trying to get the damn thing to squeal I put another few thousand miles of light braking in with no result.

Gave it to one of my colleagues and he had it going within 2 days.

Took it back and I still couldn't get it to do it. Looked through some telemetry from the data logging kit we had fitted, copied his braking style and voila! Barking dogs, glowering old people and crying children were abound.

Ken Figenus

Original Poster:

5,706 posts

117 months

Tuesday 9th December 2014
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thumbup

trickywoo

11,781 posts

230 months

Tuesday 16th December 2014
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The Wookie said:
for example pad sticky backings have been unpeeled so the pads stick to the pistons
Never heard of that before. Since when do pads come with sticky tape?

Locknut

653 posts

137 months

Tuesday 16th December 2014
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trickywoo said:
Never heard of that before. Since when do pads come with sticky tape?
I've seen those pads but I always took it that they should be left in place to avoid metal to metal contact and prevent brake squeal.

The Wookie

13,946 posts

228 months

Wednesday 17th December 2014
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trickywoo said:
Never heard of that before. Since when do pads come with sticky tape?
Some don't, some just have a grippy back plate material or even just a plain shim, but most of the pads we sell have a sticky backing that you have to peel off like this:


Ken Figenus

Original Poster:

5,706 posts

117 months

Sunday 11th January 2015
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Well its cured - all that was needed was to give it some beans! I'm normally really gentle on the brakes and lift off well in advance to slow down etc, so actually giving the brakes a bit of a workout (as suggested by Wokkie) when the opportunity arose has cured the issue. Cheers :-)

The Wookie

13,946 posts

228 months

Monday 12th January 2015
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Glad to hear thumbup