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Front brakes start squealing when coming to a stop

Posted: Thu Feb 10, 2011 6:15 pm
by sotto
Hi guys,

had my VFR for about 4 months now and the other day they just started well, squeaking is not the right word more like a honing sound then a high pitched squeal just before i stop. I checked the pads themselves they still have some ways to go before its metal to metal. When i removed the pads they were kinda easy to take out, some play between the caliper pad and disk, if that makes sense.

A few questions in bouncing around my head:
  • -Do the disk needs to be skimmed(warped, a buddy mentioned)
  • -Dust on the pads
  • -Is it suppose to be so easy to remove the pad
  • -Is it the right brakes pads i have for the VFR (aftermarket stuff :x . Previous owner didn't give me the heads up)
Its been to a mechanic already and came back the same way.

Any clue gentlemen, would really appreciate it, thanks.

Re: Front brakes start squealing when coming to a stop

Posted: Thu Feb 10, 2011 6:19 pm
by uber pikey
The gap between the disc and pads is a bit disconcerting, the squeel could be down to dust but if I were you I would check to see if your pistons are coming out freely and that the pads are free to move up against the discs on both sides.

Re: Front brakes start squealing when coming to a stop

Posted: Thu Feb 10, 2011 7:04 pm
by veefer400
Possible pad/disc contamination when cleaning etc? A good squirt with brake cleaner wouldnt go amiss, if the pads are that badly contaminated then replacement would be the only answer?

Would also advise a smear of copaslip or similar between the pads & pistons/caliper back? Are all the anti-squeal shims in place?

Re: Front brakes start squealing when coming to a stop

Posted: Thu Feb 10, 2011 7:08 pm
by hardnutdvd
veefer400 wrote:Would also advise a smear of copaslip or similar between the pads & pistons/caliper back?
:plus:
you can buy some copper grease from halfords cheap. small little tube. squeeze a dollop on the rear of the pad where each piston pushes against it

Re: Front brakes start squealing when coming to a stop

Posted: Thu Feb 10, 2011 7:21 pm
by sotto
veefer400 wrote:Possible pad/disc contamination when cleaning etc? A good squirt with brake cleaner wouldnt go amiss, if the pads are that badly contaminated then replacement would be the only answer?

Would also advise a smear of copaslip or similar between the pads & pistons/caliper back? Are all the anti-squeal shims in place?
I only did a quick check on the RHS caliper, RHS pad and the anti-squeal shim was there (doesn't mean all of them will be there). I'll remove the caliper this weekend no time right now and let you guys know what i find.

If i do need to replace is there a part no. or brand i should be looking out for?

Thanks for the info guys.

Re: Front brakes start squealing when coming to a stop

Posted: Fri Feb 11, 2011 7:37 am
by amaechizzle
If you dont have brake cleaner, pressurised water works a treat. When I mean pressurised, I mean blocking the end with your thumb.

Also don't forget to put copper grease on the brake pads slides.

Re: Front brakes start squealing when coming to a stop

Posted: Fri Feb 11, 2011 12:52 pm
by sotto
amaechizzle wrote:If you dont have brake cleaner, pressurised water works a treat. When I mean pressurised, I mean blocking the end with your thumb.

Also don't forget to put copper grease on the brake pads slides.
You mean using a hosepipe and covering the end the water comes out with your thumb. If you do then know how.

Thanks.

If you don't mind me asking what's the deal with the copper grease. :?:

Re: Front brakes start squealing when coming to a stop

Posted: Sat Feb 12, 2011 6:22 am
by amaechizzle
sotto wrote:
You mean using a hosepipe and covering the end the water comes out with your thumb. If you do then know how.

Thanks.

If you don't mind me asking what's the deal with the copper grease. :?:
If you do then know how? LOL That doesn't make sense.

Covering the end of the hosepipe with your thumb, does the same job as kinking the hose right near the end where the water would come out.
Not so much that you completely stop the flow of water, but enough to cause a restriction so that the water comes out with more force.

Copper grease helps lubricate the slides, to prevent high pitched squealing from the vibrations of the brake pad against the disc rotors.
And also "You stick it on the back of the pads, where the piston pushes. the squeak is just a very high frequency vibration... the grease damps the vibration out, stopping the squeak. "

Re: Front brakes start squealing when coming to a stop

Posted: Sat Feb 12, 2011 1:22 pm
by sotto
amaechizzle wrote:
If you do then know how? LOL That doesn't make sense. "
Lol, after I read it know I know why tou are laughing. Yes I do know what you mean. The high pressure is to blow out all the crap on the pads so that it can grip better on the disks. I'm thinking of getting the proper pads, as a back up measure.

Re: Front brakes start squealing when coming to a stop

Posted: Sun Feb 13, 2011 4:29 am
by amaechizzle
Well it's not so much about increasing the amount of grip, actually it won't increase the grip at all.

But... Most brake pads come with a chamfer on either the leading edge of the pad or both leading and trailing edges on the pad. (It's the leading edge that is the one that really counts.)
This chamfer helps decrease brake squeal.... How?

Well without this chamfer on the leading edge, you would be left with a brake pad that has a 90 degree leading edge. When there is a small lining of brake dust that would build up, during regular use, around the leading edge and in between the pad and the disc.

Quote "Pads that have not achieved a 90% SURFACE AREA CONTACT with the disc will ALWAYS squeal."

With that build up of brake dust the brake pad, when first applied, will not apply correctly against the disc straight away.

By washing the brake pads down with water, or brake cleaner, your cleaning away the residual brake dust that would be there and cause your brake squeal.

If I ever get a car with a brake squeal, first thing I always check pad thickness, as I am generally checking for the chamfered edge also. If there is plenty of pad left, I simply pull the pad out, grind a chamfer into it, put it back together, wash it all down and roadtest it.

You could go further into it, and make sure your discs aren't glazed but, don't bother until you've done everything mentioned previously.