i am having some issues with repairing the brakes on my 98 bonneville. in going through te brakes, the following parts have been replaced. m/c brake booster, pads, wheel cylinders both sides and shoes.

bench bled m/c then started to bleed the brakes. left front, and right rear would bleed fine and brakes were working, would compress. right front, and right rear however, when bleeding, pedal would not release. i know that the proportioning valeves go diagonal on this model, so that leads me to wonder two things. one that i have a small brake line leak, or two that the prop valve is not working properly.

today i am going to replace both front lines fron calipers to abs box, they could use replacing anyway.

I figure i have one or all of 3 problems, debris in system, faulty prop valve, old rubber lines.any input would be greatly appreciated.

Hey man, I wouldn't have a solution to that, but I have the same issue right now. I have replaced wheel both rear wheel cylinders and pads but for some reason the rear left pads keep baking off. There was grinding at one point also, but most of the time they just stick almost like i always have the brakes on but only on that left drum. i was also thinking the prop valve, like it isnt opening or releasing correctly and holding fluid in. No leaks yet but that is my next venture, to replace the valve.

whoops typo. I meant the shoes keep baking off.