Brake Squeal

[DN14]

so iv had this issue for a while now and it is really getting annoying now

at first i had alot of squeal though after machining my rotors i had got rid of most of all that

though now my brake starts to squeal after about 15 minutes of city driving

why is this?

ill note

brand new bendix general ct brake pads

pads bedded in & edges smoothed

new rotors very recently machined

brakes components should be all clean

anti squeal compound has been used behind pads

i know that last time i did i brake fluid flush i used dot 3 which repco rep told me was what i needed

though i found out my car actually uses dot 4 could this possibly be the cause?

Edited January 22, 2015 by DN14

[Sinista32]

Not an expert but - did the new Pads have shims on the back of them as well as applying the Anti squeal compound ?

[djr81]

No fluid doesn't cause pads to squeal.

Easiest way to try & fix it is to take the car for a drive and use the brakes alot to get them hot.

[GH05T]

poor bedding in, scuff the pads back up and re bed

[Missileman]

F***ing brake squeal, it's a black art. Some times you can over heat them when bedding them in and you will never get rid that horrid noise. You can try taking out the pads and rubbing them on a nice bit 80 grit/ concrete to freshen the surface then scuff the rotors up with 120 grit, blow off the dust on the pads and clean the rotors with brake cleaner, reassemble and do a less aggressive brake-in again.

Make a Bonfire do a little dance sacrifice a goat / neighbours cat...

[DN14]

Not an expert but - did the new Pads have shims on the back of them as well as applying the Anti squeal compound ?

new pads didnt come with shims i used the old shims for fronts, but for rears i dont have shims

F***ing brake squeal, it's a black art. Some times you can over heat them when bedding them in and you will never get rid that horrid noise. You can try taking out the pads and rubbing them on a nice bit 80 grit/ concrete to freshen the surface then scuff the rotors up with 120 grit, blow off the dust on the pads and clean the rotors with brake cleaner, reassemble and do a less aggressive brake-in again.

Make a Bonfire do a little dance sacrifice a goat / neighbours cat...

could using a fluid with lower boiling point then recommended also cause to overheat

poor bedding in, scuff the pads back up and re bed

my mechanic bed them in, he also told me if it squeaks again i need to replace pads with a softer compound one

i dont know if this is the case

[GTRPSI]

A few things to look out for on Skylines (we own a brake shop)

If they are the Sumitomo calipers (4 piston front and 2 piston rears)....

Most of the noise is from 2 places.

1/ contact points between the pad and the caliper (not rotor), shims help in that area however a little smear of copper grease between the pad and pistons, pad and caliper leading edge helps a long way, just dont get any of the stuff on the pad friction face or rotors.

2/ The calipers have a wide flat spring type clip that fits around the 2 pins that hold the pads in, this pushes down on the pads, sometimes you need to bend them a bit so to retension them to apply more downwards force on the pads.

Not enough tension pushing the pads down lets the pads vibrate, the noise your hearing is not the pad on the rotor, its the pads vibrating and rubbing on the calipers, slider pins and pistons.

Also watch out for sticking pistons, the cars are getting old, seals sweal, pistons rust up internally which will make pistons stick and not release which can glaze rotors and pads and overheat them

[kingtube69]

After having my rear pads get to metal on metal shortly after buying my car I replaced them with *surprise surprise* bendix GCT as well. No shims because they were not on there and GCT don't come with them, rotors machined etc. I've ordered new pads that come with shims so I'll swap them in later next week and keep you updated.

[DN14]

After having my rear pads get to metal on metal shortly after buying my car I replaced them with *surprise surprise* bendix GCT as well. No shims because they were not on there and GCT don't come with them, rotors machined etc. I've ordered new pads that come with shims so I'll swap them in later next week and keep you updated.

please do mate

after tons of work done on the brakes to stop the squeal they still bloody squeal, cosidering taking it in to a brake specialist now

[GTRPSI]

The factory sumitomo calipers come with stainless shims already there.

Problem is many people throw them out then blame pads for not having shims with them.....

Your supposed to keep and reuse the factory ones between the pad and pistons.

If you have pads with metal backing plates, put the original shims aside so you have them when buying pads without shims.

[Missileman]

I have Sumitomos without shims ... zero squeal, with no copper grease, and I did not throw my shims out, they are in Chinese take-away containers waiting to be needed again.

Squeal is a harmonics thang, the tightness of your whole front suspension plays a part too.

[Missileman]

walking through the city this morning, beautiful black R35 pulling up at the lights, squealed like a banshee...

[niZmO_Man]

walking through the city this morning, beautiful black R35 pulling up at the lights, squealed like a banshee...

Because race car

[GTRPSI]

walking through the city this morning, beautiful black R35 pulling up at the lights, squealed like a banshee...

We just threw a set of new EBC Yellow Stuff pads in a modded R35 the other month, he had the same issue with the factory pads, nothing but noise, new pads in for the last 2-3000Km and not a sound.

He just sold it and picked up a nice F430 Ferrari, just a few days old and wants the same pads in it now.....

No, suspension tightness has fark all to do with brake noise, its the pads vibrating in the calipers and rubbing on contact points, we had a customer here the other day complaining of noise on his Subarus Sumitomos, took one look and one side didnt have the sprung plate over the pins that presses down on the pads, the other side did have one that lost its tension from heat cycles.

Put 1 new plate in, retensioned the old one on the other side and no more noise from the old pads.....

[89CAL]

Is it a Bendix pad problem as well perhaps? I don't go near Bendix, always use QFM pads. Never had them squeal. I've got all the shims in but no grease etc. I get the occasional squeal (I'm talking maybe for 1 week in the year on a daily driver) but other then that the pads are great.

[75coupe]

Its def not a pad fault, ive used all sorts of pads and rotors, and had a squeal issue with the same pad and rotor combo im still using and went thru the whole brake squeal ordeal, its a vibration thing, project my shims was the solution for me, along with clean everything, some copper grease, just need to zero the high frequency vibrations

[kingtube69]

I had GCT on my last car and the one before that and I didn't really have any issues with them. I was pretty happy with them but the performance was a bit how do you do.

I have the GCT on the rear of my car now (not sure what's on the front) and they didn't like the heat at all last night, After a few hard brakes they started to fade which I guess is expected, just more than I thought.

Anyway, new pads come this week so I'll get the front rotors machined and swap the pads in the rear (Rotors were only machined <2,000 KMS ago.

[75coupe]

You sure its not tje fluid that was causing the fade? When did you last bleed the brakes?

[kingtube69]

Haven't bleed them at all, I've only owned the car for a month or two now. When I do the pads this weekend I might change the fluid. I was thinking about going to .4 as it says use .3 on it at the moment. Is there anything I need to know about changing . ratings? I've read somewhere you cant change from one to the other.

[75coupe]

Chances are they have never been flushed, flush all fluids, clean all calipers with brake cleaner, read up on how to bleed brakes, if you have abs read up on bleeding that too, use a decent dot 4 atleast if you goto track days consider using rbf600.

I can get too carried away with things i guess but you can easily go further than what ive written