Newbie in need of help. I have a 1984 f350 crew cab 2wd with the 7.5L 460bbl. I recently started having a noise issue with my front disc brakes. I changed out the pads and had the rotors turned. I also replaced both brake lines and bled out the system. The truck stops fine, but I am getting a constant loud squealing and metal on metal rubbing sound when I drive and when I apply the brakes. I think maybe the calipers are going bad because it sounds like the pads aren't releasing completely after I brake. the odd thing is that there is no noise when I drive in reverse or brake in reverse. Any ideas?? Thanks in advance....

 

I'd start by jacking up the front end and spinning the wheels by hand. If that doesn't reveal anything try stepping on the pedal then try spinning the wheels to see if caliper is hanging (brake dragging), but sometimes sticking caliper won't show up until brakes are hot.

Usually the "metal squeal when stepping on the brakes" happens because the pad is worn down and the "wear sensor" is touching the rotor. But you said you just replaced the pads. Is the noise the same one you heard before you replaced the pads?

Maybe backing plate is bent and touching rotor.
is the noise definitely coming form the front?

 

As mentioned, the backing plate could be bent. I'd jack the wheels off the ground and shake them top to bottom and side to side, to check the wheel bearings. If they're squealing STOP driving it IMMEDIATELY. Not only can frying to bearings do a lot of expensive damage, it can result in the loss of the wheel and a crash. (you'll also lose the brakes if the wheel comes off)
When you did the pads, did you compress the caliper piston all the way in?

 

Pads are touching the rotor, which is difficult to turn, but not impossible. Took caliper off rotor and the wheel spins freely. Definitely sure its not the bearings. I did notice a little leak of brake fluid coming from seal around caliper piston. By the way, I did compress the caliper piston all the way with my trusty c-clamp. A new caliper setup is only $40 a piece here, so replacing it is not a problem.

 

Also, the problem does get worse the hotter the brakes get.

 

Checked backing plate and it's not touching anything or bent.

 

Well it sounds like your calipers are sticking. Get a rebuilt set and you will be go to go. Also be sure that the caliper is sliding on the mounting bracket freely when you reinstall.

BTW - when you push the pistons back into the calipers; sometimes this is what causes the sticking because dirt/crud builds up behind the piston over time then when you press it back in (to accommodate new pads) the dirt/crud jams up between the piston and the caliper bore causing the sticking. it is more common with vehicles that are not driven a lot, and on older vehicles where the brake fluid never gets changed.

 

Thanks for you help. Waiting to get new calipers in tomorrow. Will keep progress posted.

 

Make sure you lubricate the caliper slides with dielectric grease, or brake caliper grease on the caliper slides-it'll make the pads last way longer because they'll wear more evenly.

 

I had a problem with one of my calipers sticking, put a seal kit in it for $5 a side. Fixed the problems I were having. My brakes would make a chirping noise going around a corner. Or going straight down the road.

 

The only thing that pulls the piston back in the caliper is the piston seal. It "rolls" when the brakes are applied and then when it rolls back it pulls the piston back a little bit. Of course this doesn't have much oomph behind it so a little bit of drag in the caliper bore can cause a problem.

 

Exactly, I have receipts when mine were replaced with the last brake job. 42,000 miles ago. The seals were a little hard and there was some sludge in there.

 

Update: Replaced calipers and re-bled the system. Grinding noise is gone, but still get the squealing. I figure it will go away in a few day since I have new pads and fairly new rotors (not very much room for pads to retract). Also replaced brakes lines. Truck stops great though, just have to live with noise until pads wear down a little. Thanks for everyone's input, it was helpful!

 

The squealing may just be a result the pad construction ("compounds" used). Premium pads tend to be nosier because they have more metallics in them. I like to use the "non-premium" (cheap) pads because they are quieter, but that also means they wear faster.
Most times the squealing/squeaking noise is coming from the pad itself and due to vibration/harmonics. You should be sure that "anti-vibration backing films/pads" are not missing or left out. These may be a thin metal backing plate that needs to be taken off the old pads and put on the new pads. Sometimes this anti-vibration pad (looks like teflon material) is adhered to the back of the new pad when you get it. Also there are aftermarket products (applied like a paste) that can be applied to the backside of the pads in a couple of dabs to help prevent noise.

 

Did buy the "premium" pads. Squeal is lessening though. I did make sure to grease everything (pad slides, and back of pads). Also the pads came with an anti-vibration backings.