Caliper not releasing.
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Describe not releasing. Nothing pushes back a caliper piston other than slight wobble of a disk.
I had one of those back in the 70's. Popped out the piston, cleaned out some debris and it started working correctly.
tonysrt
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It seems new caliper didn't help. Is the rotor locked up? Did you just install new pads? Try to back track on what has been changed. Open bleeder on stuck caliper to see if there is pressure there, or does fluid just dribble out. if pressure maybe bad master cylinder. Is it a 2 reservoir or single one? need a lot more information.
Tony Tee
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I had a brake hose go bad. Try replacing it.
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Just a shot in the dark, but was this a drum to disc conversion and the residual valve was left in the front brake output port?
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Crack the line at the master.... does the caliper release?
New problem?.. or only since changing caliper and hose?
New problem?.. or only since changing caliper and hose?
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Well apparently it didn't. Why I said crack the line.
You also didn't answer if this was a drum to disc mod, without changing the master.
You also didn't answer if this was a drum to disc mod, without changing the master.
The valve that warns you of brake problems stuck to side so fluid won't return to master.?
Moparfever65
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Sounds like a clogged line. The id of brake lines is pretty small, and rust will build up from the moisture that the fluid takes on. Disconnect both ends and blow out with compressed air to be sure.
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There is a small amount of return from the piston seal.
As the piston moves outwards from its static position (1) the fluid seal is deflected (2). When the hydraulic pressure is released the fluid seal regains its static position, moving the piston back and providing clearance at the friction pads.
ynst
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Change the flexible line. It’s probably swollen and restricting the flow back to the master cylinder.
I own THREE Dodge Magnums and, since 2008, I have had to replace NUMEROUS flex lines that were causing the calipers to seize and obliterate brake pads.
BTW, that’s not three successive Magnums, all three are currently registered and on the road and I’ve owned one of them since new.
I own THREE Dodge Magnums and, since 2008, I have had to replace NUMEROUS flex lines that were causing the calipers to seize and obliterate brake pads.
BTW, that’s not three successive Magnums, all three are currently registered and on the road and I’ve owned one of them since new.
Did you dis-assemble everything and clean every part?
Or did you do a quick change and not check for a rusty lip on the piston....and other parts.???
ynst
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I just pulled my stock of hoses and found two brand new, in the box, rear Raybestos hoses for my Magnums that were already partially plugged. Needles to say, I just binned them.
As for the possibility of having the wrong dual master cylinder due to a mistake replacing it or not upgrading to a disc/drum master cylinder if a conversion is made, it's rather easy to determine which master you have.
Nearly all of the drum/drum dual master cylinders have equal sized front and rear reservoirs. Disc/drum dual master cylinders almost always have a larger reservoir for the disc brakes and a smaller reservoir for the drum brakes.
Piston size is also different but for your problem of a stuck caliper, that shouldn't be a concern.
The problem with a drum/drum master cylinder on a disc/drum vehicle has to do with the residual valve(s) in the output ports of the master cylinder.
Drum brakes will have a 10 psi residual valve under the outlet fitting. This valve prevents the brakes from bleeding down and also allows you to "pump" the brakes to compensate for improperly adjusted (loose) brake shoes. 10 psi is strong enough to keep the brake shoe springs from forcing all of the brake fluid back into the master cylinder after the pedal is released. It, also, slows the rate of fluid return so that you can overcome the lack of braking force if the brake shoes are too far away from the drum. Each successive pump of the pedal forces the shoes out a bit further until they finally contact the drum.
Disc brakes do not require a residual valve because the pads, for all intents and purposes, don't pull away from the rotor leaving a wide gap like drum brakes do. Most early disc brake applications depended on the natural run-out of the rotor to slightly push the pads back away from the rotor but there was always a very slight drag on the rotor.
Disc brake technology improved and newer piston seals can actually drag the piston ever so slightly away from the rotor BUT ONLY ON THE SIDE WITH THE PISTON. The pad opposite the hydraulic piston still depends on the natural run-out if the rotor to create a bit of clearance and reduce drag. This, second action, is accomplished by forcing the entire caliper outwards and only works IF the locating pins are well lubricated and the caliper assembly itself is not binding on the caliper mounting bracket assembly.
Before you install the pads, place the caliper on the mounting bracket and see if it slides easily. If it doesn't, find out why.
Now, back to the residual valve. If you have a drum/drum master cylinder, remove the disc brake line adapter fitting from the casting then remove the rubber residual valve from behind the fitting then put everything back together again.
A drum/drum master cylinder won't give you the same performance on a disc/drum car as the correct disc/drum master cylinder would but it is more than adequate to stop the car but it DOES require a bit more effort on the brake pedal.
When we were drag racing our cars back in the sixties, we always made sure that they were drum/drum brake cars because the disc brake drag was good for a fraction of a second and could mean losing the race. I converted a few cars for fellow racers back to drum brakes on the front for that very reason. My late brother's '67 Camaro picked up almost a second after we did that one. (but still not enough to beat me in my GTX)
Another day of beating my kid brother down the drag strip in his 325 hp 396 with turbo 350. It was a COPO. He worked at a Chevy dealership.
As for the possibility of having the wrong dual master cylinder due to a mistake replacing it or not upgrading to a disc/drum master cylinder if a conversion is made, it's rather easy to determine which master you have.
Nearly all of the drum/drum dual master cylinders have equal sized front and rear reservoirs. Disc/drum dual master cylinders almost always have a larger reservoir for the disc brakes and a smaller reservoir for the drum brakes.
Piston size is also different but for your problem of a stuck caliper, that shouldn't be a concern.
The problem with a drum/drum master cylinder on a disc/drum vehicle has to do with the residual valve(s) in the output ports of the master cylinder.
Drum brakes will have a 10 psi residual valve under the outlet fitting. This valve prevents the brakes from bleeding down and also allows you to "pump" the brakes to compensate for improperly adjusted (loose) brake shoes. 10 psi is strong enough to keep the brake shoe springs from forcing all of the brake fluid back into the master cylinder after the pedal is released. It, also, slows the rate of fluid return so that you can overcome the lack of braking force if the brake shoes are too far away from the drum. Each successive pump of the pedal forces the shoes out a bit further until they finally contact the drum.
Disc brakes do not require a residual valve because the pads, for all intents and purposes, don't pull away from the rotor leaving a wide gap like drum brakes do. Most early disc brake applications depended on the natural run-out of the rotor to slightly push the pads back away from the rotor but there was always a very slight drag on the rotor.
Disc brake technology improved and newer piston seals can actually drag the piston ever so slightly away from the rotor BUT ONLY ON THE SIDE WITH THE PISTON. The pad opposite the hydraulic piston still depends on the natural run-out if the rotor to create a bit of clearance and reduce drag. This, second action, is accomplished by forcing the entire caliper outwards and only works IF the locating pins are well lubricated and the caliper assembly itself is not binding on the caliper mounting bracket assembly.
Before you install the pads, place the caliper on the mounting bracket and see if it slides easily. If it doesn't, find out why.
Now, back to the residual valve. If you have a drum/drum master cylinder, remove the disc brake line adapter fitting from the casting then remove the rubber residual valve from behind the fitting then put everything back together again.
A drum/drum master cylinder won't give you the same performance on a disc/drum car as the correct disc/drum master cylinder would but it is more than adequate to stop the car but it DOES require a bit more effort on the brake pedal.
When we were drag racing our cars back in the sixties, we always made sure that they were drum/drum brake cars because the disc brake drag was good for a fraction of a second and could mean losing the race. I converted a few cars for fellow racers back to drum brakes on the front for that very reason. My late brother's '67 Camaro picked up almost a second after we did that one. (but still not enough to beat me in my GTX)
Another day of beating my kid brother down the drag strip in his 325 hp 396 with turbo 350. It was a COPO. He worked at a Chevy dealership.
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