Brakes making noise on all 4 ends..replaced almost everything....what now?

[74 challenge]

My brakes are making noise from all 4 ends and I am frustrated trying to find the cause and throwing away money.

Front:

2 new calipers, rubber lines were replaced ~2 years ago all new stainless hard lines, new master cylinder, brake booster and check valve both checked and working properly, pads have TONS of material on them, proportioning valve was cleaned and repainted and all brakes bled. They make an almost grinding like sound like braking like a crappy metal caster on a cart that is starting to rust. it baffles my mind. I have taken the appart, ruibilt them greased the back of the pads....what am I missing? it has to be something minor that I am overlooking. This is also not my first brake job I have done dozens of them this is the first that didn't work.

Rear:

They squeal when braking, from highway speeds not right away but as the car slow down and from slow speeds it's very loud. I have taken the appart rebuilt them lubricated everything that moves, etc... I have tried adjusting them but now they seem to grab before the front brakes and make just as much noise. All the same stuff from above was replaced except of course I swapped out the wheel cylinders, new rear shoes, and springs. All oem stuff. Is this just an adjustment that I am doing wrong? the whole star wheel thing makes sense but I am not great at adjusting it. Steer me in the right direction.

1974 Challenger, front disc brakes, rear drums, no modifications, 318, a904, auto, power assisted brakes.

Pedal is frim, dosen't fade, stock cam... not sure what other details I can give.

[V02Barracuda]

Were the rotors and drums resurfaced recently?  I don't see anything in your post about these 2 key components. 

As for the star wheel, you turn it until the shoes are just about touching the drum.  Spin the drum with one hand and turn the star wheel until you hear friction.  Then STOP!!

Good luck.

[72cudamaan]

Squealing is the result of either a) glazed surface on drums and/or rotors or b) loose hardware or c) chatter resonating
from the back of the pad. Did you lube the contact points on the shoe to backing plate?

[74 challenge]

Were the rotors and drums resurfaced recently?  I don't see anything in your post about these 2 key components. 

As for the star wheel, you turn it until the shoes are just about touching the drum.  Spin the drum with one hand and turn the star wheel until you hear friction.  Then STOP!!

Good luck.

Drums had only a few hundred Miles on them so I never resurfaced them, same thing with the rotors.

as for lubing the shoes to the backing plate I am positive that was done.  I am going to quadruple check tonight though.

[anlauto]

Any sign of the drum rubbing on the backing plate ? Bent backing plate maybe ?

[Chryco Psycho]

Are the front rotors correct offset , the caliper brackets are clearing properly? WHat pad material are you using , Metallic , ceramic etc , sanding the surface of the pads or using a different compound or surfacing the rotor may cure it .

[anlauto]

Oh...good point ! Is the inner hub of the rotor scrapping on the dust shields ?

[74 challenge]

:

Any sign of the drum rubbing on the backing plate ? Bent backing plate maybe ?

The rear brakes spin freely with no rubbing so that one is out.

[74 challenge]

Are the front rotors correct offset , the caliper brackets are clearing properly? WHat pad material are you using , Metallic , ceramic etc , sanding the surface of the pads or using a different compound or surfacing the rotor may cure it .

This is worth a check I will also sand the pads. What grit? Should I try this on the drums/ rotors?

[dutch]

I would take off the rotors and spray them with a good coat of zinc spray. Then take it around the block. If something is scaping ,it will show in the paint.

[jimynick]

Squeals are vibrations, so that's what you're on  the hunt for. Go buy a cheap set of white box frt pads and stick 'em in, them take the car out and see if it still does it. When you put the pads in, use the proper bedding compound, not grease, on where the pad touches the caliper. The rear shoes may be glazed, since you mention they're ok until they get hot. Pull the drum and unless they're brand newish, have them fly-cut to ensure concentricity, then set the shoes inside the nice clean, round drum and using the MkI eyeball, see that they fit closely, if they do, scuff the shine off them with some 120 grit, use some Lubriplate under the shoes on the raised contact pads of the backing plate and put them back in.  The adjuster should be hand turned until the drum just goes on and after having watched for which way it needs to turn to tighten/loosen, remove the rubber plug from the back of the backing plate and use the proper tool to adjust the shoes until there's a SLIGHT drag. If it STILL squeals, turn up that old radio!