Brakes locked up

[Quisp]

It's something not letting the piston in the master cylinder get back past the return port. Pressure builds up with expansion from heat. I've seen this with aftermarket brake levers on motorcycles.

 

[Bonesaw]

Wow, this is crazy. Makes me not want to work on my brakes anyomore. I have read some horror stories on here with people doing routine stuff and then boom- mystery problems. I just swapped out my brake lines for stainless steel braided lines last night- with a bit of apprension if my car was going to be operable when done. Thank goodness all went well and seems normal- shew! lol

 

[Questionable]

Yeah, something's preventing the piston in the master cylinder from fully retracting. My master cylinder was replaced, and later the booster, so I think my problem is somewhere between the firewall to the pedal. The pedal and the hard lines are the only things I haven't replaced yet.

 

[D1JL]

Yeah, something's preventing the piston in the master cylinder from fully retracting. My master cylinder was replaced, and later the booster, so I think my problem is somewhere between the firewall to the pedal. The pedal and the hard lines are the only things I haven't replaced yet.

Don't forget the ABS module and it is between the master cylinder and the wheels.
A stuck internal valve can cause a similar problem.
This is why you should never force old fluid back up through the system when retracting the calipers to accept new pads.
You should always open a bleeder to prevent the possibility of causing a problem.



Dave

 

[Chiro6262]

Pulling up on brake peddle (came up a half inch with slight click) fixed the issue.

 

[Intuit]

I've driven behind many a vehicle with the lazy brake pedal syndrome. Arriving at a prior job, I noticed a coworker's Volvo still had the brake lights on. To keep from running down the battery I immediately went to the front office and had them announce his car over the PA. He was already aware of the problem but obviously forgot to pull up the pedal.

Some folks like to top-off their reservoir between pads. Following the old method of forcing fluid back through the system when retracting the brake piston, this results with an overfilled reservoir. In the case of the motorcycle that someone mentioned, this would cause the brake to clamp down as the fluid and parts expanded, then running out of room in the reservoir.

BTW when using the bleed valve to free up the brake piston, be sure not to let the reservoir run dry. Don't want air in that system.

 

[AnArmyOfJuan]

I can't believe that something as dumb as pulling up on the brake pedal solved this week long nightmare. My buddy and I replaced my pads and rotors all the way around last week. Tried to drive the car, rears are locked up.

Pulled the rear calipers, took them in to get rebuilt. Replaced the guide pins, made sure everything was lubed up nicely, re-installed the calipers, bled all four corners and topped off the fluid between bleeds. Took it for a test drive, seemed fine. Did the bedding procedure, felt like it was dragging a bit, but not bad.

Let everything cool down and went around the block again, brakes locking up again but with intermittent severity.

Read this thread, say "F" it and pull up the brake pedal. Car immediately rolls freely, even after engaging and disengaging the parking brake.

I'm going to wait an hour and take another test drive once everything is cool to the touch, but I'll be damned if this isn't the dumbest yet most effective fix I've heard yet!