Brake squealing. Metal with metal sound in rear
 

Hey whats going on guys. I tried searching online to find what it could be causing this metal to metal sound but cant seem to find anything.

Car is a 1986 trans am with a 1989 formula 3.45 rear end disc swap. A friend and i recently changed the rotors and pads front and rear. I purchashed the rotors (wearever) from advanced auto parts along with ceramic brake pads (wearever). I replaced only the front calipers.

As soon as i pull out of my friends house ,and start driving home everything is fine till i get on the road and can here a squeak squeak coming from the left rear tire. The squeaking countinues and only STOPS whens i press on the brake. As soon as i let off the brake the squeaking starts AGAIN.

Also when i make a hard left turn i can hear a real loud and annoying metal with metal screach. We raised the car took the wheel off and noticed the heat shield on the brake pad was off the pad and rubbing on the rotor . I set it back in place and took the car for a spin . It was still screaching and only when i would press the brake would it stop. The metal with metal sound went away for a moment when making a hard left but returned after a 10 minute drive!!

After the storm passes im going to return the rear rotors and pads and have them replaced for another set. What can the problem be? The car has steel braided lines in the rear. Could it be my rear caliper needs to be replaced ??? Or is it something much simpler??

Any input would be great help.

Did you put anything on the backs of the pads? You can rather buy that Disc Brake Quiet (it's red), use some high temp anti seize or high temp RTV. The noise is more than likely the outter brake pad wiggling around due to a bad wheel bearing on that side.

yes finally a thread that doesnt begin with "for sale"

could possibly be a seized piston on the caliper.
lift it in the air and step on the brakes let go, then try to rotate the wheels by hand

No we didnt...and It was the outer pad that was lose. So this would be the symptoms of a wheel bearing? and not the caliper?

Ill try that as soon as the storm passes. IF the wheel doesnt spin then it would be the seized piston on the caliper right? if it does spin then im guessing it would be the wheel bearing like zraff suggested? I just want this damn noise to go away...i cant stand it..it drives me nuts....makes me want to get out of the car and start kicking it lol...

yes. kicking works aswell

Probably crap pads, shims hitting, or maybe the pads aren't returning off of the rotor due to fitment etc.

thanks for the info guys... any other probabilities?

When a rear caliper seized on my G35, that wheel got noticeably hotter and had more brake dust as well.

Is the rotor contacting the brake bracket? Had that issue on my '94.

Did you check to make sure the caliper wasn't sized on the sliding pins? Once you do a simple pad swap the thickness of the new pads create havoc if the caliper can't center itself.

wheel/axle bearing?

my truck did that, turned out to be the shim that the brake pad rests on. a tab broke off and it hit the rotor

True, that happened with the back brakes of my truck. The clip on the end of the caliper had the little nubby part break, and it was rubbing the top edge of the rotor. And also the backing plates rusted up and were rubbing to rotor too ... :lol:

OK this is my UPDATE..... thanks for the info guys....so me and my friend ..we take a look at the rotor and notice the bolts holding the caliper where actually hitting the inner backside of the rotor...the bolt was actually grinding off....Also the caliper bracket was flush with the front side of the rotor....that had to the the reason it would squeal so hard making a left turn.

(my car is a 1986 trans am....with a 1989 formula rear end disc) I tell him to call the autoparts store so i can use his discount...he call to have a new set of rotors replaced for the rear...i go ahead and give him the part # for the rear rotors....(he has the guy on speaker) the guy said we dont have that part# for the rear we have another....WTF!!!...i know i gave him the correct part# the first time......the only explanation for this either HE or the auto parts guy got me 1986 rotors all around since i did buy front rotors as well....Funny thing is the right rear rotor was fine and not rubbing the rotor with the bolots or bracket.

I looked up the spec for 86 rear rotors and 89 rear rotors.. the 86 were 1.03 inches in width 89 was .73.....a .30 DIFFERENCE......the diameter for the 86 was shorter than the 89..that is why the bolts were hitting it in the rear....

We installed the new rotors today and no longer were the caliper bolts hitting the rear of the rotor nor was the bracket flush against it the front of them....I FINALLY thought this NIGHTMARE was over....

I pull out to drive and its STILL SQUEAKING,,,,,BUTTTT no longer is it rubbing metal with metal when i hit a hard left...so im guessing that problem is fixed..but still have the squeaking problem from the left rear side.

Now what would be the only other explanation????? we removed the caliper...I engage my EBRAKE and see the caliper piston come out, but when i release the EBRAKE it wont retract it stays in the same place....would this mean my CALIPER is seized OR can this be fixed by adjusting the EBRAKE cable OR is it my brake line? i have stainless steel lines... Is this one way to tell that i need a new caliper????

I would also like to add that the when i pull the ebrake ,,the caliper stays siezed only on the left rear caliper and retracts when i push it back in manually .....but works perfect on the right caliper..... Would this be the parking brake cable? or is it for sure my left caliper just seizing and my parking brake cable is fine ????

I dont want to replace the whole caliper if its just the parking brake cable.

Any info would be greatly appreciated..thanks

The disc brakes in the 3rd gens before 1989/1990 were trash especially because of the proportioning valve. Your pistons may have build up on them, preventing them from gliding back smoothly, common on rear caliper pistons with cars that brake fluid is never/rarely bleed from the system. I hate to say it, but I would buy a Centric rebuild kit, and clean/rebuild that calipers to see if that fixes the problem, if not, well you may be on your own. Also Advance brake products are trash, should of at least went with Auto Zone or NAPA.

from my understanding 1982-1988 where iron calipers...and 1989-1992 where aluminum....they are still trash..though i heard the 82-88 were much worse..i had drums in the rear prior to the swap.... my rear end now is off a 89 posi borg warner 3.45 .

The Centric rebuild kit is to rebuild the caliper??? Can i just buy an aftermarket one? I thought autozone was trash lol.....thats why i went to Advance :facepalm:

I would also like to add that the when i pull the ebrake ,,the caliper stays siezed only on the left rear caliper and retracts when i push it back in manually .....but works perfect on the right caliper..... Would this be the parking brake cable? or is it for sure my left caliper just seizing and my parking brake cable is fine ????

I dont want to replace the whole caliper if its just the parking brake cable.

I believe the 9 bolt setup you have came with aluminum PBR calipers, with the parking brake assembly built in to them, like the one the LT guys have. The problem with 3rd gen rear setups is that they had a recall and redesign of the proportioning valve for the 82-88 design after they found out they were doing little to almost no braking whatsoever in the rear! There is a site where someone goes over upgrading the brake system, and needing to pick up a 90 or 91-92 prop valve to make it work right.

Since you had drums in the rear, you most likely need a disc brake rear designed master cylinder as well since it may have been designed for the drum setup and not disc. If the master cylinder isn't pulling the piston back in the caliper, it's probably because it was setup to pull the pistons in the wheel cylinder, and also doesn't require as much pressure to push wheel cylinder pistons, as it does to push caliper pistons. So take a look at a 90-92 Disc master cylinder, that should help, or at minimum, you've upgraded a 25+ year old part on your car. and what ever you do DON"T GET A REBUILT ONE!!. Calipers are okay to get rebuilt, but any other hydraulic part.....just don't.

Centric sells both just a rebuild kit AND rebuilt calipers. Unless your calipers were toast, I would just rebuild them, the kits are cheap. I just bought two rebuild kits for the 3000GT VR4 front calipers for 5 buck a pop off amazon. Do your homework first and make sure the Centric part numbers match what your purchasing. when you take the pistons out, look on the surface and see if there is black stuff, or any oxidation/rusting. Take a soft or mild scotch brite pad, clean them up. Make sure to use brake fluid as a lubricant.
As a veteran of Advance Auto, I can assure you their brakes are the ****tiest of ****. not a day went by where we had to defective exchange pads or rotors. :lol:

heres a couple sites to look at:

http://www.3rdgenformula.com/modification/brakes.htm

http://www.thirdgen.org/techboard/br...rformance.html

Also the prop valve DEFINANTLY has to be upgraded to a disc style, otherwise it'll continue to pressure the amount for drums, so find a 90-92 Camaro or buy one new. No U-pull it will allow you to purchase one for insurance reasons, so good luck finding one. I had that problem with my 1996 Camaro. Rear wasn't braking at all, wasn't until the inspection station put it up on the brake test that I found out, so I had to buy an LT1 ABS/Prop unit.

Thanks for the info BLACDOUT96.......i appreciate it.....

One question though...if it was the prop vavle..wouldnt it be affecting both sides and not just the left? i asked this same question on another forum and they stated

"What you're experiencing sounds like the common symptom of a bad soft line acting as a check valve."

I have stainless steel lines.....can stainless steel lines go bad??

Anything can go bad, but stainless steel aren't as easy to make go bad as compared to an ordinary line. I still recommend changing to the correct master cylinder and prop valve, you won't hear the passenger side as well as the driver since it's closer to yoy. If your worried, first inspect te caliper and caliper piston and see if there is build up on it. I'd still purchase a caliper rebuild kit jut I case any bad seals break while inspecting.

UPDATE...... ended up raising the car up from the rear end..took my wheels off and put the car on Drive......



When i put the car in Drive...what i noticed was the the whole disc would Wobble which was causing the pads to hit back and forth....The wobbling looks very bad .....the right side doesnt..only very very slighlty..not as bad as the left side thats making the squeaking sound..



Now my question is....what part do i need to change to fix this???? The mechanic said its the Left side Axle... Is he not Bsin me?

As i stated before i have a 1989 Borg warner 3.45 rear end....i know parts for this rear end are supposedly harder to come by....any parts and part #s will be great...thanks for any info guys.

Before you put it in drive, did you torque the lug nuts down to proper spec? Only way your axle would move far is if your c clip went bad, or a bearing went bad. If the face of the axle went bad, well that would be first I've head, but if the rear axle hit a curb by sliding into it, I guess it would be possible. Take the rotor off, and clean any rust, or crap built up on it, also check to see if the rotor isn't out of round, I wouldn't be suprised if the advance auto rotors were bad, especially if they stocked them on the shelve on their sides instead of laying flat.

Swap the rotors side to side and see if the problem stays or follows.