jsp9r

Hi folks, I'm looking to pull from the wisdom of the collective here on my Suburban parking brake issue.

The E-Brake on my 2004 K1500 does not have enough tension to hold the vehicle on anything beyond a perfectly flat parking lot.

Here is what I have tried so far:

I have pulled both rear rotors and confirmed both parking brake shoes still have some meat on them and don't appear to be damaged in any way.
Both rear drum surfaces are free from any grease or other slippery substance that would be causing issues.
I have dismantled and cleaned both rear adjuster mechanisms and then pre-set the brake shoe loading just shy of having the brake drag when the rotor is installed.
Given the brake would not hold with the adjustment nut (just underneath the drivers side in front of the rear wheel) fully tightened, I added a sleeve over the threaded part of the adjuster shaft that gives me the ability to tighten it about another full inch.

Using the shimmed up adjuster, I can get it tight enough that there is significant drag from the rear with the p-brake pedal fully released. Even with this much pre-load, it won't hold the vehicle when I fully depress the brake pedal.

The last thing I did was visually inspect each lever actuator in the rear when the p-brake pedal is moved and I can verify that both sides are in fact deploying when the pedal is pressed.

The only other thing I can think of would be cable stretch but it just does not feel like that. Pedal seems to be fairly firm when I depress it and I just cant imagine that much stretch.

Oh, I never really use the p-brake so this could have been busted for ages, or been a slow decline for all I know. It was discovered when it failed a state vehicle inspection.

Any thoughts on what I might be missing here?

Thanks in advance!

repairman54

I would suspect a bad cable or the brake lining is glazed over and loss of friction to hold. I had the lining break off on my '11 and with fresh ones it holds better on the boat ramp.

Cusser

I'd rarely drive our former 1988 Sub, 1994 Sub, 2005 Yukon and have really driven our May-acquired 2011 Yukon. I always would use the parking brake, and Mrs. Cusser NEVER uses it, just puts in "Park". And she isn't going to change no matter what.

So on the 2005 Yukon, never had to replace the rear parking brake in 11 years and 180K with that....

tech2

pull on the cable by hand and watch the levers move....if they are moving the complete range of travel....the shoe is not adjusted up enough...it should drag at set up. this is best illustrated on dead axle fwd vehicles....you spin the wheel by hand and it should turn 1 turn. Hard to do on an rwd and axle attached but you get the point.

when adjusted properly the foot lever should be ratcheting 4 to 6 clicks to fully applied.

jsp9r

Hmm...this really points to improper rear shoe adjustment then: both rear levers will go through the complete range of motion and the drivers side will actually lever out to where the back of the arm hits a suspension component.

So...In adjusting the rear shoes I was adjusting them out until I could not get the rotor back over the shoe and then just backing off a turn or so until I could slide the rotor on without having to drive it on. And I also loosened the shoe retainer clip a little and pushed the rotor on to make sure each shoe was nice and centered and then retightened the clip. Not sure if that was overkill but I was grasping at straws at that point.

I can go back and spread the shoes out a turn or two and then use some force to get the rotor in place and see what that does for me.

hanky

What I have done and most of the time it helped.
Apply the parking brake, then attempt to drive forward. Usually the vehicle will move without too much throttle. But when you back up the shoes lock up and the brakes hold better. In a safe place with the parking brake applied, ,not hard, drive a few feet and maybe some burnishing will help with more and better contact between the shoes and the inner drum
.It is not necessary to drive the vehicle with the parking brake on more than a few feet, then release the brake and reapply it to see if the braking has improved.

jsp9r

@hanky, thanks thats a good suggestion for cleaning up the brake shoes. It has made me recall an old trick from auto racing days when we used to put a smear of valve lapping compound on the pads to help bed in a new set of pads really fast.

tech2

when adjusting....i do a coarse adjustment then put the rotor on....apply the ebrake ...this centers the shoes to the rotor hat. release and then set the final adjustment.