And sometimes Master Cylinders go bad for a reason. For instance, it's more common than people admit to, but wrong fluid contamination swells all of the "rubber" parts in the hydraulics, the Master Cylinder is just the first in line. And once those seals in the Master swell, they 'seal really good', and they don't release pressure on the return stroke after that.
If you see any swelling of the "diaphragm" or "bellows" that is on the bottom of the fill cap, the master has probably been topped with the wrong fluid, ie PS fluid, Oil, etc...
Bad master cylinder. Stop driving it NOW and get it fixed. Your brakes are dragging as you go down the road.
Replace your master cylinder. They have one way valves that impede the return of brake fluid so that pumping the brakes does something. Your valves are bad. But that is the breaks, not the brakes.
if some one put oil in master cylinder by mistake. form heat oil will swell and slowly put brake on till lock up , get a clear glass of water stick finger in master cylinder brake fuiled will turn white and drop to bottom, if iol in it oil will float to top , that's how you tell . and if iol is preswnt have to flush break system with presser bleeder and new brake fuiled , have fun
sounds like the master cylinder is bad.
it is a 2002 GMC sierra, the breaks works good when you first start driving but the farther you drive the harder they get. After about 10 KMS the pedal is so hard that you can not push it down, I still have good stopping brakes just can't budge the pedal. The brakes get so hot that they smoke by times and when you stop at a light or stop sign you have to give it a lot of gas to start moving again. then after you stop and shut the truck off for awhile the pressure will release and the breaks will be back to normal until you start driving again.
