2009 Tahoe LTZ 4x4 Parking Brake sudden failure

[PatDTN]

I was trying to get my Tahoe to hold on a fairly steep hill and SQUASHED the parking brake on. As I stepped down on the pedal it popped and slammed to the floor. No more parking brake at all.

I looked at the cables figuring I had popped the end off one. Nope. All good. I just forgot about it for a while.

Now I find myself with enough time to check things out. I pulled the right rear wheel because I remembered I had a leaking axle seal there. Things were all gooey back there as I expected. That's likely why I had to step on the pedal so hard to make it hold.

I can't really see anything wrong to cause the parking brake to fail completely. The pedal goes through full travel with no resistance though it does tell me the brake is on when it isn't pulled all the way up by hand.

My rear rotors are worn out and the pads are worn unevenly inside vs outside so I'm going to get all the brake parts for both sides. I want standard one piece backing plates since I'm pulling the rear axles to also replace those leaking axle seals. My diff cover is badly rusted as are the bolts.

Oddly I can add a rear diff cover to my order at one site but when I try to get just a gasket for it it wants to know more specifics about my differential. ?? Not for the cover; that was just one choice. Somehow to get a gasket for that I need more information than I know.

What kind of can of worms am I opening here? I see getting to the diff cover means lots of really rusted parts have to be removed. Is it likely the backing plate has failed some way to cause the parking brakes to fail??

 

[dnt1010]

Sounds like you are from up North? 10 yrs and a vehicle is rusted out and done,. Trade that puppy....

 

[PatDTN]

It was a Virginia vehicle. I'm guessing from the fact that much of the rear of the vehicle is rusted he used it to launch a boat in the ocean and thought you had to get WAY into the water.

Can't afford to swap out the vehicle. It's an LTZ and I love my air conditioned seats.

 

[PatDTN]

Well I finally figured it out. The middle cable was broken inside its rubber sheath. It looked fine but when I was pulling on various cables that one suddenly got longer. :-O Feeling along it there was a limp section with no cable inside the sheath.

 

[avalonandl]

I hate it when it goes LIMP ......

 

[PatDTN]

New cable in plus all new parking brake stuff inside the wheel. How do I adjust this? Going searching soon...

 

[swathdiver]

New cable in plus all new parking brake stuff inside the wheel. How do I adjust this? Going searching soon...

The parking brake shoes are supposed to be a 1/4 of a millimeter away from the drum. You have to release tension on the cable by lifting the pedal all the way up and inserting a screwdriver through a hole on the side of the actuator and then set about replacing the shoes and adjusting them back aft.

When I did mine, I didn't really get it right. The pedal went down quite a ways and over time the travel increased and the hold was less and 18 months later they have all but stopped working again. I bought an old school brake shoe caliper to measure them with when I finally get in there to get them working right again.

At the same time, I'm thinking of going with the JNC push to park/release pedal assembly inside of the lever release mine came with. All three cables have to be changed and for the conversion, parts will run a little less than $150 for all GM OE. Going to buy new parking brake shoes just in case though.

Anyway, get the procedure from AllDataDIY or your shop manual to adjust them right.

 

[PatDTN]

Thanks. I've watched videos on the whole thing. Oddly nobody really addresses some of the issues I found. That single nearly circular brake shoe can move up and down across the actuator so that the top or bottom can hit the drum while the opposite side has clearance. No easy way to measure and center that up.

Once that's done measuring the circumference of the shoe vs the inside circumference of the drum should get me closer but I'm going to just pull it, adjust it, put it back on, until it's too tight and then back it off some.

 

[swathdiver]

Thanks. I've watched videos on the whole thing. Oddly nobody really addresses some of the issues I found. That single nearly circular brake shoe can move up and down across the actuator so that the top or bottom can hit the drum while the opposite side has clearance. No easy way to measure and center that up.

Once that's done measuring the circumference of the shoe vs the inside circumference of the drum should get me closer but I'm going to just pull it, adjust it, put it back on, until it's too tight and then back it off some.

It moves around without the drum in hat rotor on but doesn't have so much freedom afterwards! Just measure the spread distance across about halfway down and it is supposed to be .024 of a mm less than the inside diameter of the drum! I tried to eyeball that and failed. Bought the tool for next time. Then again, maybe I didn't adjust the tension on the cables right or something.

It was NO FUN pulling the rotor off when the shoes were adjusted out too far, 15 minutes to remove the rotor without wrecking the shoe.

 

[PatDTN]

Yeah, I'm facing that on one side but the adjuster is all the way in so who knows what went wrong.

Thanks for the tip on measuring.