Disc pads dragging on rotors

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OldJoe54

OldJoe54

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1975 Duster, slant 6, auto, had factory installed disc brakes on front, drum on back. Last trip out on long cruise. After we had been driving for a while, over an hour, we noticed whenever I had to apply heavy pressure to the brakes, we heard a grinding noise. Light pressure on the brakes, we didn't notice the noise. After returning home, I pulled one wheel. The rotor surface is wearing unevenly, looks to have plenty of thickness still but but due to the unevenness of the wearing probably should be turned. I could not pull the caliper off, more to come about this. What I could see of the pads, they seemed like they have thickness still although I could not measure them to be sure. I removed the 2 bolts/brackets that hold the caliper in place but the pads are tight against the rotor surfaces. The pads being tight against the rotor is the reason I couldn't get the caliper off. So my question is, should these pads be this tight or should I be looking for a specific problem? Thanks in advance.
 
Tight is subjective. They all drag some. You likely have a stuck piston, perhaps from gum/ rust etc in the caliper. You should be able to work a big screwdriver in there and work it in a few different places between the caliper and pad backing, just to crack it loose a bit.
 
I always used a c clamp to push the piston back then remove the caliper. Then I removed the ridge on the outside perimeter of the rotor. Cleaned up the sliding surfaces and lubed them sparingly with never seaze. Reassemble and if they still don’t move freely, you have to pull the caliper apart and address the piston issue, clean, repair or rebuild.
 
Oh, by the way, take your cover off your master cylinder before compressing the piston and go slowly to avoid making a mess.
 
Could be a problem or it could be normal... The calipers don't "retract" so the pad is always in contact with the rotor... But it shouldn't cause significant drag on the rotors.. If the rotors are getting hot without applying the brakes then something is wrong...

Get the car up in the air, have someone try turning the wheel while someone else presses the brake pedal, as soon as the pedal is released the wheel should turn pretty easily...

If it doesn't turn easily try cracking the bleeder screw... Initially crack the screw loose then re-snug it... Have someone press the brake pedal and when they release it crack the bleeder, if fluid dribbles that's normal, if it spurts something is causing it to hold pressure... Could be a master cylinder, could be a hose....

Of fluid dribbles but the wheel still binds check the caliper for sticking & the caliper mount for binding...

Let us know what you find..
 
Not normal at all. While there's no springs to retract the pistons the "knock back" from the bearing clearance in the hubs should let the rotors be free of the pads if the brakes aren't applied. Either way if you've unbolted the caliper it should slide off, unless something is still holding pressure in the caliper. If there's a grinding noise, then either you've gone metal to metal somewhere on the pads or it could be that you're losing a wheel bearing.

The internally collapsed brake hose is usually the culprit if the issue is only on one side. It can happen with really old or even brand new brake hoses, and you can't tell from the outside. The fluid usually pushes past the collapse when you step on the brakes, but it's enough to hold pressure on the caliper side of the collapse so the brakes drag.

If it's both sides then it's more likely a master cylinder issue, but it could also be an issue with the brake lines above the point where they split.

One sided can also be a caliper piston seal or a piston that's sticking in the bore.

Sliding calipers can also bind up between the caliper and the caliper bracket, but, the pistons should still move freely in that case.
 
I had this issue on both sides years ago. I made an alum. spacer to go between MC and firewall. I later learned there is a plastic one for it I did not have. This was on 1974 style disks. If it just one side probably sticky caliper.
 
An update, it was a stuck caliper on the driver side. Once I freed it up, it started working properly. I still need to replace the pads, they are wearing unevenly, but I consider that to be minor, just have to find a place that stocks them. Thanks everybody that responded.
 
OldJoe54,
I have *** N.O.S. *** O.EM. MOPAR *** in the MOPAR BOX !!!
It doesn't get any better than that --- N O T expensive, either !!!

P.M. me, as per forum rules, if interested......
Craig.....
 
^^^ Keep in mind, that is all the cheapie Chineseum garbage ^^^ that will rip up your Rotors to smithereens as it " attempts " to stop a car.....

If you love your car, you don't dare use that garbage.....
 
mobileparts said:
OldJoe54,
I have *** N.O.S. *** O.EM. MOPAR *** in the MOPAR BOX !!!
It doesn't get any better than that --- N O T expensive, either !!!

P.M. me, as per forum rules, if interested......
Craig.....
Click to expand...
Ok, I don't know the forum rules on P.M.ing, nor am I sure how to do so.
 
I bought rebuild kits. But after i made sure calipers and pistons were not pitted. A quick cleaning, blast, hone, high heat paint. And reassembled. I think it was better off than cheap rebuilds of suspected crappy quality. That way I know the bodies and pistons condition versus unknown rebuilds. Once your good cores are gone they are gone.
If yiu have Amazon these are good cheap pads.

Amazon product ASIN B01LWSTS8D
 
OldJoe54 said:
1975 Duster, slant 6, auto, had factory installed disc brakes on front, drum on back. Last trip out on long cruise. After we had been driving for a while, over an hour, we noticed whenever I had to apply heavy pressure to the brakes, we heard a grinding noise. Light pressure on the brakes, we didn't notice the noise. After returning home, I pulled one wheel. The rotor surface is wearing unevenly, looks to have plenty of thickness still but but due to the unevenness of the wearing probably should be turned. I could not pull the caliper off, more to come about this. What I could see of the pads, they seemed like they have thickness still although I could not measure them to be sure. I removed the 2 bolts/brackets that hold the caliper in place but the pads are tight against the rotor surfaces. The pads being tight against the rotor is the reason I couldn't get the caliper off. So my question is, should these pads be this tight or should I be looking for a specific problem? Thanks in advance.
Click to expand...
4 piston Kelsey Hayes calipers?
 
Hey 340six ,
Did you enjoy the FREE egg roll with that purchase ???

It is critical to get that free egg roll delivered, excuse you can't stop your car until a quarter mile past a Chinese food place.......
 
mobileparts said:
Hey 340six ,
Did you enjoy the FREE egg roll with that purchase ???

It is critical to get that free egg roll delivered, excuse you can't stop your car until a quarter mile past a Chinese food place.......
Click to expand...
I am not giving away my old USA Wagner and Raybestos drums or rotors as,well pads or shoes.
The Op is not the only one reading this thread.
So you can get off your high horse. As for as the ones i mentioned goes are fine all as the Element 3.they are both good pads. Not everyone can get NOS.
And for a new car same goes.
Stay away from.the cheap Rockauto 12 buck or what ever cheapie.
But to state all new pads made elsewhere are junk is not true.
If you have NOS parts great PM and sell them.
News brake they stopped making NOS parts. Some guys have to make do with the best after market they can find.
 
Last edited:
mobileparts said:
^^^ Keep in mind, that is all the cheapie Chineseum garbage ^^^ that will rip up your Rotors to smithereens as it " attempts " to stop a car.....

If you love your car, you don't dare use that garbage.....
Click to expand...

What’s the coefficient of friction for your ancient asbestos pads? Do you even know?

Most modern brake pads have much better coefficients of friction. I know you’re just an opportunist with a warehouse full of asbestos, but friction creates wear. If you’re saving your rotors, you’re not stopping your car.

But anyone buying NOS wearable parts is probably driving a show pony anyway, not actually driving their car much.

I see you’re still skirting the business rules here by not becoming a sponsor to actually sell your parts, just jumping in and belittling people into sending you a PM. Classy.
340six said:
I am not giving away my old USA Wagner and Raybestos drums or rotors as,well pads or shoes.
The Op is not the only one reading this thread.
So you can get off your high horse. Fast is the ones i mentioned and Element 3 are both good pads. Not everyone can get NOS.
And for a new car same goes.
Stay away from.the cheap Rockauto 12 buck or what ever cheapie.
But to state all new pads made elsewhere are junk is not true.
If you have NOS parts great PM and sell them.
News brake they stopped making NOS parts. Some guys have to make do with the best after market they can find.
Click to expand...

Yeah, only old cars with NOS pads can stop right?

He does this all the time. It’s just because he has a warehouse full of outdated asbestos brake pads and hasn’t figured out that technology didn’t stop improving 50 years ago. Modern pad compounds far exceed anything NOS that these cars had. Sure, there are cheap pads out there that aren’t great quality, but there are also plenty of brake pads that will out stop anything NOS for these cars.
 
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