1984 fj60 with 3 year old brake master that’s been braking fine for the last 5 years after I replaced front rotors/pads and rear shoes. Just two weeks ago started noticing a stiff pedal getting off the interstate, and subsequently a significant brake drag without pull to one side while driving. I assumed the brake booster was the issue, and installed a new one. I’ve triple checked the booster push pin and have actually shortened it to the point that it’s much shorter in comparison to the old booster. I’ve also confirmed the length of the pushrod inside the cab, and I’ve got about .25 inches of travel before the brakes engage.
Despite all that, I can’t get the brakes to stop dragging and then locking. When the lockups occur, it’s after I’ve driven around 3 miles or so, and all four wheels begin to drag, and even without further compression of the pedal they increase drag until they lock. I’ve confirmed all four lock by jacking each up individually. The brakes release when I loosen the brake lines from the master, and fluid is released.
When the truck is sitting still and cool before driving, the back wheels feel free, and there’s enough drag on the front that they both only spin around 3/4 turn with a good push around (I don’t know if that’s normal).
I hate to keep throwing parts at it, but I think it may be the master cylinder at this point, but I can’t explain why all four wheels would gradually drag with worsening until they lock up. Any thoughts or suggestions are very appreciated.
Despite all that, I can’t get the brakes to stop dragging and then locking. When the lockups occur, it’s after I’ve driven around 3 miles or so, and all four wheels begin to drag, and even without further compression of the pedal they increase drag until they lock. I’ve confirmed all four lock by jacking each up individually. The brakes release when I loosen the brake lines from the master, and fluid is released.
When the truck is sitting still and cool before driving, the back wheels feel free, and there’s enough drag on the front that they both only spin around 3/4 turn with a good push around (I don’t know if that’s normal).
I hate to keep throwing parts at it, but I think it may be the master cylinder at this point, but I can’t explain why all four wheels would gradually drag with worsening until they lock up. Any thoughts or suggestions are very appreciated.
