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

 

noone????

 

I would bleed the brakes first to see if the piston rod is not stuck out a little and making the pad rub on the rotor will driving. Also make sure brake pads are in correctly and not popping out.

 

I am having the same problem. I recently changed out the axle bearings, thinking that they were the culprit. No dice. I had my differential rebuilt. Still there. I am thinking about buying new alxes, but am beginning to get annoyed that I can't fix it.

 

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????

Any info would be greatly appreciated..thanks

 

Bleed the brakes first, the caliper could be seized, it would either have to be rebuilt or buy a new one. If you can't press the piston back down it's either seized or has a lot of air in the lines.

 

I am able to push the caliper back down easily with my hand....

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.

 

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

JamesC

 

Are you engaging and disengaging the parking brake while the caliper is off the rotor?

 

A bad soft line? What line would this be? the ebrake or brake line ?

 

Yes the caliper is off the rotor on the left side .... But I did leave it on , on the right rotor...it seemed to be retracting fine so I didn't remove it ... Should have I ?

 

The 89 rear should have a soft line going to both calipers.

JamesC

 

Sorry for my dumb ?s ..... So this is the stainless steel lines I have going to each side ? Or would this line be a different rubber line ... ? You wouldn't happen to have a picture?

 

Two hard lines run along the axle, one to each side, then turn to soft lines to the calipers (the OE is rubber. Many members, however, use braided steel, which covers the rubber and/or teflon, IIRC).

You might find a pic in the following link:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC

 

2 hard lines run to each side or they split to 1 each side?
So it would be my stainless steel braided line I should change ? The one going to the caliper?

 

hey james thanks for all the info....when it comes to brakes on here i know u have the best advice...

I asked on another forum and they said this

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"

"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."

Ive been doing some reading...is this necessary?? can this also be the problem? The guy i bought the rear end off told me i didnt need to change the prop valve.......but he would say that since he was selling and installing it for me.....

If it was the prop valve wouldnt it affect both sides and not just the left side????

 

If OE rear end was equipped with drums or with standard disc brakes and the 89+ rear end is equipped with PBR's, the appropriate combination valve is the choice of the best braking performance.

The combination valve will effect both sides equally.

EDIT: Don't worry about the master cylinder.

JamesC

 

Is it a squeak or a squeal? Ceramic pads can squeal and if that's the problem then try some duct tape on the back (not the side that contacts the rotors) of the pad. If that eliminates the squeal then remove it and apply some of the goo they make for this. Either way remove the duct tape after the test.

 

The later disc brake rears will make the metal to metal squeeking noises on turns if the caliper bracket is not perfectly centered over the rotor. C-clip axles have end play which moves the rotor in and out. The caliper brackets are hard mounted to the axle tubes. On turning the axle/rotor moves to the outside of the turn and the rotor can rub the caliper bracket if it is not centered. GM used shims (long since discontinued) between the axle tube and the caliper bracket mount to center them from the factory. If a new rotor has a slightly different offset, and they all seem to, this can move the rotor closer to the caliper mounting bracket. The easiest way to fix it is to use thin washers in between the caliper bracket and it's mount till the rotor is perfectly centered. The PITA way involves adding shims like GM did (which you have to make yourself) between the axle flange and the mount bracket. To do it this way you need to pull the axles out to get to the shim location behind the caliper bracket mount.

 

The shims can be seen in the link I provide above. Shims are readily available from AndyZ28:

http://www.andyz28.com/catalog.htm

JamesC

 

$56.50 plus shipping for 4 brass shims that are hopefully the right size?!? Washers are around $.15 each.

 

Since GM used shims that's the route I took (though several years ago when I purchased them, they were only about half that price), but each to his own.

JamesC

 

I can comfirm that you may need to change master cylinder. Some master cylinders contain a residual check valve this keeps 8-16 psi in your rear wheel cylinders on a fron disc rear drum system. You will allways have slight pad drag if you do not change this. This drag might not be bad at all but there will never be clarence between your pads and the rotor.

 

You may find the following from GM interesting:

The higher brake pedal effort associated with 1982-84 Camaro cars equipped with four wheel disc brakes may be a source of some customer comments. The J65 brake system was designed with a low pedal ratio for reduced free travel and a firmer and higher effort pedal for the high performance buyer. Owners of J65 equipped Camaro cars not sharing this interest and desiring reduced brake pedal effort can be accommodated by replacing the original production master cylinder assembly with the appropriate J50 master cylinder unit specified below.

JamesC

 

Is this because of master cylinder bore size? Differences in hydraulic advantage? im having a hard time understanding that. looked it up on all data said the same thing.

 

Scroll down a bit in the following link for master cylinder specs (also take a peek at the note at the bottom of that section):

http://lukeskaff.com/?page_id=333

JamesC

 

I guess I dont see any difference in the two disc disc ones except year and thread pitch. I might not be seeing what you are. heres the part numbers for J65 and its replacement J50.

ORIGINAL J65 REPLACEMENT J50
MODEL YEAR MASTER CYLINDER MASTER CYLINDER

1982-83 18009370 18009367
1984 18010574 18010572

 

so from reading the article...to my understanding is the master cylinder is fine ...mine originally being from a 86 rear drum set up going to a 89 disc set up... right?

 

Right.

JamesC

 

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 shaft that is bent... ?? 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.

 

Would this be the part i need ? # 1 on the diagram?
http://www.newgmparts.com/parts/1989...diagram=MHP100

#1 on the diagram says its the axle shaft...

If im replacing the axle shaft....would i need to replace the # 2 (on diagram) axle seals and # 3 shaft bearings????? Or would i be fine not replacing them?

im thinking i would atleast need to replace the axle seals.... right?

 

someone helping me on another forum said this

" 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. "

Is it possible for the axle shaft to be bent? or is it just the Shaft Bearing???

I did get hit in the rear about 4 months ago. my dad back up into the car pulling out of the driveway hitting it in the far left quarter panel.

i read that the borg warner 9 bolts dont have c clips.

""All 9 bolt rears for f-bodies use 28 spline axles.
Another advantage over the 10 bolt is it uses pressed on tapered axle bearings allowing the axles to be bolted in instead of using c-clips.""

So if its not the c clips it would be the Shaft Bearing im guessing (# 3 on this link in the diagram ) ?

http://www.newgmparts.com/parts/1989...diagram=MHP100

I dont want to replace the Axle Shaft if its just the Shaft Bearing.
So a Bad Shaft bearing would cause this very noticeable wobble ? ?

another question...if i do end up replacing the Shaft Bearing or the Axle Shaft..im guessing i would need to purchase new Axle Seals ? ?

How hard of a job is this ?

 

I am having this same problem right now terrible squeling/squeaking sound only when turning left can't figure it for the life of me. Goes away also as soon as the brake is touched. It's pretty much consumed my mind for the last few months can't find the culprit. The few times I have driven my car in the last couple months I cringe every time I turn left.

 

Mine sounded metal with metal when i was turning left because i had the wrong rotors on the ca...the bolts were hitting the rotor...but the squeak squeak is my axle flange that is bent

 

Come get your axles!

 

James ?

 

YEa, I saw your post on NJFBOA too