palmaceae

OK, about ready to give up, I replaced the pads on the rear drums on my '86 GT because they were worn and were squeaking. I replaced the pads, the hardware and the wheel cylinder. The problem I am having now is the drivers side squeaks when I first apply the brakes, but when you press the pedal further down the squeak stops. But I can feel both rears grabbing and the drums gets real hot, plus you can smell the pads burning, and the pedal feels a bit mushy when they get hot. I have everything installed correctly and adjusted, like I mentioned above everything has been replaced in the back and the drums look good. Can this be caused by a bad distribution valve, master cylinder or hoses? That is the only thing other then the brake lines that have not been replaced. What would make the rears grab, what am I missing?

jacostang

Have you checked the fluid and made sure the lines are clear? The fluid looks clear and not brown or dark?????

svopaul

It is possible that your proportioning valve is stuck.....brake fluid should be changed at a minimum once every 2 years and should be clear. If your brake fluid is not clear, it is toast.....Brake fluid by nature absorbs moisture and that is created by the heating and cooling cycle they go through. If your fluid is dark or black then it is possible you have a stuck proportioning valve.

jacostang

I have not changed mine in long time.. Weekend here I come...

Puter

You did not turn them?

palmaceae

It was dark, but bled them. But would old fluid cause this?

palmaceae

Proportioning valve, that is the word I was looking for, not distrubution valve! This was the next thing I was going to replace, because it makes the most sense.
BTW, are new proportioning valve available at local auto parts stores?

palmaceae

Yes, forgot to mention that.

jacostang

Dark fluid is bad for all components, Dirt and Moisture like Paul said carries rusty crap all through your brake sysytem...

svopaul

No, they are not. Your best bet is to take it apart and clean it. There are O-rings in there and it can be rebuilt. Sludge build up from lack of fluid changes can cause it to seize up.

palmaceae

Thanks, can I get the O-rings somewhere?

svopaul

Take it apart and see how the O-rings are...you may be able to reuse them if not hard and brittle or you can carry them to your local auto parts store and choose from their selection of O-rings. Worst case you can buy an O-ring assortment kit from Harbor Freight or Northern Tools.

palmaceae

Thanks!
I do not look forward to taking the lines off the block, they look a little corroded on the outside (where the nut joins the line, turn the nut the line moves with it), hopefully a shot of WD-40 will loosen them up.

svopaul

Make sure you use a line wrench and you can use a hammer to tap the wrench and hopefully shock them loose.

palmaceae

Just to let you know you were right! The valve was stuck and quite dirty when I opened it up. I cleaned it first but still had the problem (while bleeding the rear brakes, no fluid would flow when pumping the pedal) but took it apart again and made sure nothing was sticking, now all works well. I would still like to replace it if I could find one!
Thanks again!

svopaul

Glad it worked out....you should not have to replace it once it works again. Just make sure to change the brake fluid in the system at least once every 2 years and you will not have another problem.