Disc brake squeak when not braking

[TJ Hopland]

In the last 40 years of dealing with disc brakes I have never had one squeak when not braking.   I put new pads in the 73 a while ago after a CV boot blew grease all over everything and ever since there is a light squeak unless you put slight pressure on the pedal.   

I have never used any special grease or glue.  If the pads come with some kind of sticker like thing I do use those and I install the clips that come with the new pads.  I'm talking about single piston floating calipers, nothing fancy.   So whats the issue or trick?

I'm asking because I think its the side that I just noticed blew a CV boot so its coming apart tomorrow when the new axle comes in and if there is something I can do to fix the squeak tomorrow will be the day to do it.

[cadillacmike68]

This is almost always a vibration. The pads are vibrating in their slots.

It's such a high rate that it sounds like a squeak or squeal. Put some (a lot) disc brake quiet which keeps the pads from vibrating.

[Cadman-iac]

This is almost always a vibration. The pads are vibrating in their slots.

It's such a high rate that it sounds like a squeak or squeal. Put some (a lot) disc brake quiet which keeps the pads from vibrating.

I refer to this stuff as "Anti-chatter matter". It does work well for stopping disc brake chatter or squeal.
Rick

[fishnjim]

Maybe not from the brake?   
Grease got on something else like a pulley.
Manufacturing variation is common too.   So maybe the new pad and clips aren't too.   
Otherwise the rotor could be warped a bit and engaging the pad causing it to move with no force on it.   The newer pad have wear sensor squealers, so check for those hitting.
It's certain that if this was not happening before it's related to the incident and repairs.   

[cadillacmike68]

If the squeak goes away with a light touch of the brake pedal, it is not a pulley or belt.

[TJ Hopland]

Yes it goes away with a very light touch on the pedal.  Also takes maybe 30 seconds to come back after you let off.  Doesn't seem to do it under 10 mph.  I think it does it at high speeds but there is so much other noise you just don't hear it.

When I pull the pads I should see some wear marks where this movement is happening right?   And that is where the brake squeak stop goes?

[Cadman-iac]

 Actually it goes on all the backing surfaces that make contact with the caliper. The outer pad is mostly on the ends, the inner pad is just around the piston. 
The best stuff I've used is an orange color and if memory serves it's just called Disc Brake Quiet.

Rick

[TJ Hopland]

I will have to pick some up when I go get my axle which will hopefully be soon.  It rained last night so with a few hours of sun the garage is going to get mighty hot and sticky,  would rather be out for a cruise than sweating in the garage.   

Thanks for the tips.

[Big Fins]

Permatex Disc Brake Quiet. It could be blue, it could be orange. I guess that would depend on the date of manufacture. Spray all 4 pad backings and the outboard pads should have 'ears' that you cinch onto the caliper to hold it tight.

[Cadman-iac]

Permatex Disc Brake Quiet. It could be blue, it could be orange. I guess that would depend on the date of manufacture. Spray all 4 pad backings and the outboard pads should have 'ears' that you cinch onto the caliper to hold it tight.

Yes, Permatex,  that's the brand I've been using. I didn't know they changed the color on it though. I haven't had to buy some for years.

Rick

[cadillacmike68]

This is almost always a vibration. The pads are vibrating in their slots.

It's such a high rate that it sounds like a squeak or squeal. Put some (a lot) disc brake quiet which keeps the pads from vibrating.

Yes, as I initially stated.

[TJ Hopland]

I had 3 choices at the parts store.   Permitex came in a decent sized aerosol can for about $9.  There was also a smaller Gunk version for about the same price.   Last option which I decided to take was orange CRC stuff in a squeeze bottle for $6.    Seems like in the past I remember it being a paste sort of thing.  Spraying seemed like it could be messy so we will see.....

[Big Fins]

It's been a spray since I started working for Cadillac in 1974. We just layed the pads on the open box and shot them, dry to tacky, then install.

[savemy67]

Hello TJ,

I have used the spray, but I prefer the squeeze bottle of the CRC Disk Brake Quiet.  You can apply as much or as little right where its needed.  The spray applies to where it is needed and not.

Some GM disc brake pads come with ears that sit in a notch in the caliper.  Once installed on the car, the ears are supposed to be clamped hard to the caliper.  I use a 24 inch long groove joint plier followed up with a brass drift and hammer.  Result - no squeak or squeal.

Respectfully submitted,

Christopher Winter

[TJ Hopland]

Yes 15 or so years ago someone told be about crimping the pad to the caliper and since then I have been doing it.  Not sure if it helps or not but I have done it.   I have a larger than usual Channel-Lock pliers that has worked well for me.

The everywhere vs where it needs to go is one reason I chose the tube rather than spray.   

Getting the parts turned out to consume all my motivation for the day so looks like this will be tomorrows project. 

[cadillacmike68]

I use the CRC stuff. Squeeze as much as you need out and spread.

As to the crimps, some years have them some don't. I think all these years from 1968-1996 should have them, but the kits do not always include them because it is not a wear item, and sometimes they get lost over the years.

[Finndorado]

I also have an annoying squeak from right front wheel and thought it was the caliper/pads, because it`s brake was jamming few times.
The squeak is louder driving straight, and almost silent in curves and when braking.
Caliper, pads and fluid hoses were changed but the squeak did not disappear.
So now the axle(s) and bearings are going to be changed. That right side CV boot seems to be intact and clean, maybe the axle is just dry.
I cannot imagine what else to do with my squeak..

[TJ Hopland]

I had a major lazy attack the last couple days and the weather wasn't really screaming 'drive your classic' so it hasn't really been an issue that its in the garage in pieces.  Maybe today......

[TJ Hopland]

Wow what a drawn out pain in the rear project this simple oil change turned out to be.    Its back together now but since its cold and raining today I didn't take it out to see if I actually fixed anything or not. 

Since I was re installing used pads I was able to see where they were contacting the caliper so I put the orange goo in those areas which was 2 rectangle shapes on the outer one and 2 chunks of the circle of the piston on the inner.   

I never really looked close at the back of pads especially these before.  What ever the material is on the back of the plate it must be reasonably soft.  It appeared to be riveted to the backing plate and was pretty squished in the contact areas. 

I assume this orange stuff is more or less glue?  And its supposed to make the pads stick to the piston or caliper?   I saw a wear mark on the top part of the caliper where one of the shoes must have been rubbing but was assuming that I should not put anything there.   Glue would not be good since the pad needs to move there and grease no good since its really close to the braking surface? 

[cadillacmike68]

Wow what a drawn out pain in the rear project this simple oil change turned out to be.    Its back together now but since its cold and raining today I didn't take it out to see if I actually fixed anything or not. 

Since I was re installing used pads I was able to see where they were contacting the caliper so I put the orange goo in those areas which was 2 rectangle shapes on the outer one and 2 chunks of the circle of the piston on the inner.   

I never really looked close at the back of pads especially these before.  What ever the material is on the back of the plate it must be reasonably soft.  It appeared to be riveted to the backing plate and was pretty squished in the contact areas. 

I assume this orange stuff is more or less glue?  And its supposed to make the pads stick to the piston or caliper?   I saw a wear mark on the top part of the caliper where one of the shoes must have been rubbing but was assuming that I should not put anything there.   Glue would not be good since the pad needs to move there and grease no good since its really close to the braking surface? 

It's more like a cross between silicone and rubber cement. To dampens vibrations by being in between the metal parts. It stays where you put it (within reason) and comes off easily with brake cleaner.