When I put my 2000 tj on the road this spring I had done the brake lines,calipers,pads and rear brake spring kit. I had not replaced the rear pistons.No abs. Everything till now has been great for 5,000 miles. Brake pedal hard . Now as I sit I notice the pedal start to slowly go down. No leaks anywere. probably the master cylinder I suspect. Anyone run into this?
Is my brake master cylinder bad?
- Thread starter bruceco
- Start date
Sounds like it could indeed be your master cylinder, especially if it's just started happening and you're sure you're not losing fluid.
b0xcar
TJ Enthusiast
I would also bet on the master cylinder going bad. Mine did this before eventually going out on me. Luckily I was at a car wash (on an incline) waiting to get in the bay before the pedal went straight to the floor. I started rolling backwards. I was able to limp it home. Changed the master cylinder and all was good.
That does sound like a master cylinder as other have said since you have no leaks. It means the pistons aren't holding fluid. Fluid is most likely slipping by. If your brake pedal is hard, but the car is not stopping is most likely the brake booster. That is usually how I tell the difference.