97 Tahoe RR Brake Sticking and Won't Bleed.

[wirlybird]

Hi all,
I have a 1997 Tahoe LT 4X4 2 Dr.
The right rear drum brake sticks. Has been doing this for a long time.
Some years back I had the rear brakes done with all new parts including wheel cylinder and drums. Problem is still there.
Pulling away from a stop light or sign, for instance, you step on the gas and feel a slight resistance in the truck moving forward then a "clunk or thump" from the rear and it starts to roll. After driving some the RR wheel is quite hot compared to the left one.
Another thing to note is the dealer, after adjusting rear brakes and trying to replace brake fluid, said they could not bleed the RR but had no further diagnosis of that issue at the time.
So my question would be - what do you think the most likely cause is for this?
Master cylinder would seem unlikely.
ABS components? Something else?

Thanks for any ideas.

 

[bsamole]

I would replace the r r wheel cylinder since it won't bleed. If that doesn't resolve the issue I would check the e-brake a cable for binding.

 

[wirlybird]

I would replace the r r wheel cylinder since it won't bleed. If that doesn't resolve the issue I would check the e-brake a cable for binding.

Wheel cylinders replaced a few years back along with all rear brake components. I can only assume it bled then. Seems like a cheap start but doesn't account for the brake sticking since it did it before.
E-brake is never used but stranger things ...

 

[wirlybird]

A little more research and I think the proportioning valve is part of the ABS unit. Is this true?
I do think my ABS is having issues. Last time I jammed the brakes I don't recall getting that noise and vibration.

Considering the age maybe a good idea to replace the ABS unit?

What do you think?

 

[exp500]

Replace Both rear wheel cylinders, Ilike using new hardware kit too. Bleed brakes well. Actuating ABS on Downstroke. Will take at least 2 QTs.

 

[east302]

Does left rear have the same issue?

If it works but the right doesn’t, then I’d say it’s an issue in the brake line, too far out adjusted shoes or a wheel cylinder problem. The rubber hose meets at a tee-type fitting on top of the rear differential. From that, there’s a hard line each to the left and right.

With the drum off, does the right parking brake lever move freely when you push on it?

Is the drum stuck on compared to the left? Shoes could be sticking in a groove on the backing plate, so that’s maybe another option.

ABS wouldn’t be my first guess since there’s one line that goes from the combination valve to both rear brakes.

 

[wirlybird]

Does left rear have the same issue?

If it works but the right doesn’t, then I’d say it’s an issue in the brake line, too far out adjusted shoes or a wheel cylinder problem. The rubber hose meets at a tee-type fitting on top of the rear differential. From that, there’s a hard line each to the left and right.

With the drum off, does the right parking brake lever move freely when you push on it?

Is the drum stuck on compared to the left? Shoes could be sticking in a groove on the backing plate, so that’s maybe another option.

ABS wouldn’t be my first guess since there’s one line that goes from the combination valve to both rear brakes.

You've basically cover most of my questions.
Dealer tried to do a fluid flush and said it wouldn't bleed at the RR.
I asked if they pulled the bleeder to see if it was plugged. Asked if the left bled. No responses.
I didn't think the ABS had anything to do with it initially. I also figured that it was one line to the back and a T at the rear end. Should have been an easy issue to find why it didn't bleed. Lazy tech I think.

Took it back to the dealer today and said "what the hell!" why didn't anyone try to determine WHY it wouldn't bleed.
It is going back Monday to address the bleed issue and to try and resolve the sticking brake. AND make sure both rears actually are working ok.
We'll see if we get anywhere with this.