Brakes sticking

[mauro12]

Hello everyone. I’m asking you your advice about my brake problems .
2 months ago I decided to replace many parts of the braking sistem : discs , pads , hoses , master cylinder and fluid . Since than , my problems started to appear . I had the front right caliper sticking while I was driving in the motorway .
I brought the car to my personal mechanic , who inspected the calipers and realized that they were full of old fluid inside and quite dirty . The rear one were sticking badly . He was able to unclock all pistons and the car was driving fine apparently.
Yesterday I drove the car 1 hour in motorway and after I came back , I realized that the rear wheels were extremely hot at the touch and there was also some burning smell .
I came to the conclusion that these brakes overheat while I drive in motorway . What is your view on that ? Is only a caliper problem or something else ? The discs are new and they are the same size as the original ( I bought genuine ate ) . Honestly I don’t know where to look .  Any help is appreciated . Thank you

[Pawel66]

Have you adjusted the hand/parking brake?

[Cees Klumper]

Since you replaced the brake hoses we can rule out the most likely cause.
I seem to recall there may be an adjustment to the brake pedal-to-booster connection possible.
When you lift the front of the car, do the wheels spin freely? What about after you apply the brakes?
If it's not the brake pedal adjustment, I would probably remove the calipers and rebuild or replace them.

[zoegrlh]

Yes replace or re-build the calipers.

[roymil]

In addition to all of the other good suggestions I suggest also thoroughly flushing out the hard lines with brake cleaner fluid.   I had one line that had a lot of internal contamination and buildup that was restricting flow of brake fluid that noticeably slowed the response both in application and in release of the brakes on one wheel.  It would have been difficult to replace those hard lines so I just kept flushing them until the fluid was clear and I could tell the restriction was gone.

Also agree that parking brake maladjustment could cause rear wheel heating but also don't forget to check the rear proportioning valve that regulates both rear brakes.   If it hasn't been rebuilt, you should check it out.

[mauro12]

Thank you guys for your suggestions . I just came back after 2 hours of motorway drive with my mechanic . The car was normal . We’ve checked the temperature of the wheels with a thermometer gun and was normal . About 38 degrees Celsius . We jacked the car and the wheels were spinning freely . Probably some air bubbles in the sistem or some slight settlement with new pads . I will monitor the situation by the way . Everything is new and should work fine .

[stickandrudderman]

The symptoms you describe might have any one or more of the following causes:
Swollen brake hoses
Sticking calipers
Seized counter-lever inside servo mounting.
Insufficient clearance between brake pedal and push rod.
Insufficient clearance between servo push rod and master cylinder.
Master cylinder
Blockage in the pressure differential valve (if fitted)

It most certainly is not caused by air in the lines.