Very squeaky brakes after new pads

[Otispunkmeyer]

Is this normal? Had the MOT done begining of februrary now and they advised new pads, but the disc's where fine. Honda wanted a lot of money and so I went to Tanvic (always done ok by me in the past), who did the job at a much more reasonable price.

However I am now thinking I should of just paid the extra! I know pads take a bit to bed in but its been over a month and they still shreek and squeak loudly at the lightest touch on the pedal. Whats more some stabs at the brake pedal result in an odd grating/grinding sound (and you can feel it through the pedal). In addition they seem to chirp and squeak while you are just driving along! They are rubbing somewhere.

Somethings not right I am sure. I am guessing some of it is down to likely poor quality el-cheapo brake pads. But given the sort of "trundle-wheel" chirping going on as you drive along (doesnt always do it mind) I am guessing one of the discs is warped slightly. There's no evidence of scoring so theres no foreign object wedged in there. There is also a back-plate arrangement behind the discs but these show no sign of interference that I can see and from giving them a prod, would guess they make more of a low pitched scraping noise instead of a high pitched shreik.

I've been doing some pretty heavy braking in an attempt to wear the pads down but the noises so far persist!

Do I just continue hoping they will wear enough to stop or go back to Tanvic as ask them to adjust the calipers/fit less cheap pads?

[JAHetfield]

Take pads out, coat back with copper grease and refit. Should cure the problem.

[Cupramax]

I'd go back and ask if they put some copperlsip on the back of the pads... this is the most common reason why pads sqeal. The copper slip stops them vibrating which causes the noise. otherwise, just wip them out yourself and put some on... Halfords sell it in tubes.

[Ozzie Osmond]

Otispunkmeyer said:

Honda wanted a lot of money and so I went to Tanvic (always done ok by me in the past), who did the job at a much more reasonable price.

There's your answer.

However, what I would do is,

• drive the car for a while and see if it settles down
• if not, try the copper grease route

Manufacturers put considerable efffort into engineering brake materials which don't squeal. Aftermarket parts are not so rigorously tested.

If you drive sensibly it may well settle down. I'd advise against following the advice of anyone who says "give it a few hard stops". Just normal driving and wait...

[Otispunkmeyer]

There was definitely copper paste on the back of the pads. I checked when I got the car back. It was visible on the back of the pad where it shows through the frame of the caliper. But, how does copper paste on the back of the pad do anything? (EDIT: read above... curbs vibration)

Ill have them look at it again. I wanted to fit new discs as well anyway, but everyone told me not to. Im guessing its just cheap pads.

Edited by Otispunkmeyer on Thursday 15th March 15:18

[mwcr85]

Otispunkmeyer said:

There was definitely copper paste on the back of the pads. I checked when I got the car back. It was visible on the back of the pad where it shows through the frame of the caliper. But, how does copper paste on the back of the pad do anything? (EDIT: read above... curbs vibration)

Ill have them look at it again. I wanted to fit new discs as well anyway, but everyone told me not to. Im guessing its just cheap pads.

Edited by Otispunkmeyer on Thursday 15th March 15:18

Take it back to where you got the work done and see what they say? It probably will be the combination of new pads and old discs, they often get a small lip on the outside due to wear.

[Decky_Q]

The grease might be there but its possible they didnt put enough, or used the old rusty shims or put the new ones on the wrong way round (easy with no rust to guide you) or summant, brakes are a real easy maintainence job that anyone can do with just 1 spanner and vice grips, I know that you priced around and probably dont want to do the work yourself but taking the caliper off and checking everything is in its place is very do-able and would take around 20mins to get wheels and calipers off and check both sides. With new pads in, you wont even need to wind the caliper back or anything its super easy if you want to do it and plenty of help available here if you feel stuck or unsure.

[BusaMK]

How many miles have you done on the pads? Mine took about 200 to stop squeaking when I upgraded to Yellowstuff, and that was with new discs.

[chryslerben]

STOP STOP STOP now I know everyone is going to flame me and shout me down on this but covering the back of the pad in copper grease is going to do nothing toward stopping the squealing.

Theres a reason manufactures put sticky backings on pads, its to keep the pad in contact with the caliper so when you lift your foot off the brake pedal it also pulls the pad away from contact with the disc to eliminate squeal. Covering it in copper slip may actually make your problem worse.

Now a little copper grease on the ends of the pads where they locate in the carrier is ok to stop seizing.

What I suspect your problem might be is new pads on old disc or the friction lining on the pad isn't upto spec.

A quick test to see if its friction lining would be to remove the pad and see if the contact surface is shiny compared to the normally mat finish of a new pad then lightly rough it up with abit of scratch then refit and test this is normally the cause of brake squeal whilst braking. This is of course if you've not got a sticking caliper but as your garage haven't advised it.

[PhillipM]

They don't put sticky backings on pads, they might put rubber type backings on there, but that's just to dampen vibration to reduce squeal.

[Krikkit]

They'll often put a retaining spring/clip on the back of the pad to hold it in the caliper so it releases cleanly, but I've not heard of any which are stickied.

[S8QUATTRO]

PhillipM said:

They don't put sticky backings on pads, they might put rubber type backings on there, but that's just to dampen vibration to reduce squeal.

They do, some pads now come with a 3M sticky shim on the back. Quality pads anyway as its extra cost.

[PhillipM]

Yeah, but usually it's sticky on the side that goes to the pad...it being sticky on the other side I could see reducing noise by offering further damping of the system through the adhesive sticking to the piston, but usually if the piston comes back then the pad will push back enough from runout and debris on it's own anyway, shouldn't need retracting.

Edited by PhillipM on Thursday 15th March 18:42

[penryar]

Personally I'd take the pads out, file a small chamfer onto the leading edge of the pad, copper slip on the backing plate and refit. Should remove all squeal until they've bedded in fully.

[Fish981]

chryslerben said:

STOP STOP STOP now I know everyone is going to flame me and shout me down on this but covering the back of the pad in copper grease is going to do nothing toward stopping the squealing.

Theres a reason manufactures put sticky backings on pads,

[...]

They don't.

HTH

[S8QUATTRO]

PhillipM said:

Yeah, but usually it's sticky on the side that goes to the pad...it being sticky on the other side I could see reducing noise by offering further damping of the system through the adhesive sticking to the piston, but usually if the piston comes back then the pad will push back enough from runout and debris on it's own anyway, shouldn't need retracting.

Edited by PhillipM on Thursday 15th March 18:42

Not sure exactly on the above, but i'm invloved in the OE/Aftermarket parts business. Quite a few decent quality pads now come with this 3M sticky back shim, already stuck to the back plate, but still with it being sticky on the other side too. Lots of different shims now though, rubber, metal, sticky back, smooth, textured etc.

[Jimmyarm]

Metal shims in the caliper carrier have probably bent and are touching the disc if you are getting a constant noise.

Just take it back to where you got them fitted and they will fix it

[Eggman]

chryslerben said:

when you lift your foot off the brake pedal it also pulls the pad away from contact with the disc

...but then again, maybe it doesn't.

[chryslerben]

PhillipM said:

They don't put sticky backings on pads, they might put rubber type backings on there, but that's just to dampen vibration to reduce squeal.

funny that fitted a set earlier with 3m adhesive on the back.

just to clarify can somebody actually explain why applying copper grease to the back of a pad will stop squealing caused by the friction lining?

As much as I probably do sound abit patronising which I really dont want to it would be nice to solve this myth about copper grease on pad backings solving squeal.

[OllieC]

chryslerben said:

PhillipM said:

They don't put sticky backings on pads, they might put rubber type backings on there, but that's just to dampen vibration to reduce squeal.

funny that fitted a set earlier with 3m adhesive on the back.

just to clarify can somebody actually explain why applying copper grease to the back of a pad will stop squealing caused by the friction lining?

As much as I probably do sound abit patronising which I really dont want to it would be nice to solve this myth about copper grease on pad backings solving squeal.

it worked on two separate capris I had...

both had the metal shims fitted but the copper grease stopped the squeal, I have no idea how it works

it is good to put on the retaning pins (depending on the caliper design i suppose) to make them easier to remove when you need to change the pads again