Q: Hard brake pedal and rear brakes locking up.
I had an issue with a spongy pedal so I replaced my rear wheel cylinders as it felt like my back brakes were grabby. I got the new ones on and had absolutely no brake pedal. Trying to fix the problem I put a new master cylinder, brake booster, a brake line I found was leaking, a booster check valve and bled the brakes a whole bunch of times. My pedal is now hard and it seems like the front brakes aren't doing anything and the rear brakes want to lock up unless you barely tap the pedal. I've since dropped it off at the dealership but would like to know some possible causes of the problem.
My car has 223000 miles.
My car has an automatic transmission.
Hi. I will help you with this issue you are having with your 2001 Durango. Unless you bled the master cylinder, it is possible there is still air in the system. If you car is equipped with ABS, air could have also gotten trapped in the ABS modulator. If ABS equipped, a bi-directional scan tool would be essential to manually activate the ABS system to clear air from that segment of the lines while you are bleeding the system. It is also possible that in all of this work somehow the proportioning valve has been affected causing the desired pressure differential, front versus back, to get out of spec. Using a 2,500 PSI gauge, you can check the pressures at each wheel and that will definitely give you a clue as to which brake circuit is the issue (or both), whether the proportioning valve is working properly and whether the line pressures at each wheel are within spec. Should you need a second opinion, by all means feel free to contact YourMechanic for assistance and we will diagnose and repair the issue for you.
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