I have a 1995 Pontiac Firebird 3.4L V6 automatic with ABS brakes. When I drive the car between 5 to 10 miles, the right rear brakes begin to bind, eventually locking up the right rear wheel.
I changed the brake shoes, both drums, all springs, the piston at the top and greased the self-adjusting rod. Also I took off the master cylinder and cleaned out the reservoir (there was a lot of gunk in there). I also separated the reservoir from the master cylinder and cleaned the gunk from the inlet holes (there was a ton of slimy stuff in there). I then put it back together and did a 'bench bleed', mounted it back in the car and bled the brakes.
I was able to drive twice as far as I did before the bleeding but after 10 miles the issue returned.
I always notice a high pitch but not too noticeable squeak that begins about 2 miles before they lock up. I'm assuming it?s the beginning of the brakes beginning to push against the drums. When I apply push on the brakes (as I'm driving), the squeak stops but the squeak returns as I start driving again.
Next the brakes become really hard, almost as though the brake lines are full of pressure. When I stop at a stop light and take my foot off of the brakes, the car doesn't roll forward at all. Then eventually the brakes lock up against the drums. The car must sit for about 45 minutes until the pressure is released and I'm able to drive it again. At that point, it is as though there was no issue at all, the brakes work perfect again until I get to the 5 to 10 mile range.
It seems to me that the brakes are building up pressure in the lines to the right rear brakes but it never releases that pressure. It seems as though every time I press the brakes, it keeps that pressure in the lines until the pressure is too high to allow for the drums to turn.
What could be causing this issue? Could it be that 'Proportioning valve? If so, does the 1995 firebird have one and where? I can't seem to find it at parts stores.
Could it still be a bleeding issue? I successfully bleed the rear until the fluid ran clear but the front caliper bleeding valves on both sides were too stuck. I was unable to bleed those.
Could the ABS hydraulics cause this issue?
What could cause for only the right rear brake drum to lock up?
Any and all suggestions are appreciated.