Never seen this before - Parking Brake Shoe Replacement Help

[cmatt]

176k miles, vehicle specs in sig. @swathdiver @Doubeleive @petethepug and anyone else. A couple weeks ago, I replaced my rear pads and rotors. I noticed the RR parking brake shoe did not have any pad material left on the metal ring. There were no pad material chunks or excessive brake dust. The LR side was fine.

So I ordered parts and set about replacing the parking brake shoes. Got the parts swapped out without issue until I tried to reinstall the RR rotor. The adjustment was all the way in and I was barely able to get it on. Forget about it rotating. What gives? What am I missing? Maybe the last guy removed the pad material so it would fit?

 

[mikez71]

Could be. Try swapping rotors if possible.

I have purchased some parts store brake pads that were just too thick.
Went to another store, material was thinner, everything worked fine.

I know you got the Delco pads, but maybe the rotors were changed before and one was out of spec?

 

[89Suburban]

Are you sure the PB cable or linkage is hanging up?

 

[cmatt]

Checked that and seemed good. LR has good clearance and engagement.

 

[Doubeleive]

I would guess without being able to have a closer look that there is a issue with the parking brake hardware
I am a bit confused by your photos? looks like you replaced a axle and some hardware? can't tell which side is which and what was replaced or not replaced, per side anyway
in any case try measuring both sides and see what's up
the old parking brake shoe does look like it was worn down to nothing but probably happened a long time ago, maybe someone drove it around with the parking brake applied.

 

[Fless]

It looks like the lining/shoe is too wide in the middle of the shoe, but I also don't like how the ends of the lining seem to be apart from the metal shoe. Maybe too much or lack of adhesive, or the horseshoe is bent? Is the lining the same way on the other side?

In the olden days (LOL) at times we had to arc (so, grind) the linings to match the roundness of the drums. Asbestos was an issue then but I'm not sure it is now with modern materials.

How to arc brake shoes to drums? - Chevy Message Forum - Restoration and Repair Help

Chevy Forums FREE technical assistance for your restoration and repair. Model specific subject matter experts, classified ads and more.

www.chevytalk.org

Switch shoes side to side. Switch drums/hats side to side.

 

[tom3]

Might rotate the disc several times and see where the rub marks are on the little shoes. Maybe a little bit of material removal could free it up. Should have a really good EM brake when done I'd think.

 

[petethepug]

VW liked to do a little feckery where the used the same high performance front caliper and pad from an earlier solid rotor set up on …

a later model vehicle with a bigger, vented rotor and the same brake pad, only it had 1/2 the brake material on it.

This was done to accommodate the thicker vented rotor at the expense of thinner pads. Both the thin pads & thick pads had the same part # followed by an A, B, C, etc.

That little bit of difference in brake pad thickness caused all kinds of fits when trying to reassemble things. Does GM make a set of pads specifically manufactured with thicker brake liner material meant for another model??

 

[cmatt]

Thanks for all the input. Please keep it coming. I'll address the questions that I can. Couple other bits of info is that I purchased this vehicle in June of 2020 with 132k miles. Since then, I've used the parking brake a small handful of times and it engaged and released with no issues.

Also, to reiterate, a couple weeks prior, I replaced both rear rotors and pads with AC Delco sourced from my GM parts guy using my VIN. That's how I noticed the RR park brake shoe. Strange thing is the LR park brake shoe looked like it had been hardly used aside from just being dirty. Is there such a thing as the park brake cable(s) being out of adjustment between the left and right sides?

Here's a view of the LR park brake shoe when I initially removed that rotor.

LR side partially cleaned up

@Doubeleive all the photos in my first post are of the RR. The first pic is when I initially removed the rotor. No axle or hardware was replaced, just cleaned thoroughly. The only item attempted to be replaced was the parking brake shoe. The last pic is attempting to show the lack of clearance between the rotor hat and the shoe with the adjuster all the way in.

@Fless agreed on how the lining looks. The horseshoe isn't bent. I compared to the original one and it's a near perfect match for the arc. Thanks for the link. I'll check that out.

@tom3 notice the spots indicated with red arrows. I believe that may be the main rub areas.

@petethepug I'm not aware that GM did such a thing, but that doesn't mean that they didn't. Unfortunately the OE rear rotors and park brake shoe have been discontinued. So I had my GM parts guy give me what they use which is the Delcos.

 

[Fless]

I don't know the GMT900 chassis as well as my GMT800, but if it's anything like mine the parking brake cables come in four pieces. The intermediate cable may (should?) have an adjuster and an equalizer where the two rear cables connect:

One or both of the rear cables could be stretched or broken, too, which would cause issues engaging the parking brake. The whole mechanism where it goes through the backing plate should be carefully inspected for correct operation. I'm curious as to what you'll find.

 

[Doubeleive]

how does the cable look? it should be attached to the panhard bar, I haven't ever heard of anything like this so maybe double check that you have the parking brake pad installed properly and compare each side and inspect both sides carefully inside and out.
doesn't make sense though if the adjustment is all the way in

 

[Doubeleive]

I don't know the GMT900 chassis as well as my GMT800, but if it's anything like mine the parking brake cables come in four pieces. The intermediate cable may (should?) have an adjuster and an equalizer where the two rear cables connect:

View attachment 440457

One or both of the rear cables could be stretched or broken, too, which would cause issues engaging the parking brake. The whole mechanism where it goes through the backing plate should be carefully inspection for correct operation. I'm curious as to what you'll find.

are the parking brake pads left/right designed? like standard brakes? I have only done mine once or twice and I don't recall, I assume there are identical though

 

[petethepug]

The easiest way out of this dilemma is to assume it’s a parking brake cable adjustment issue.

A close look at the rear of the left & right assemblies and cables will tell if someone has been in there before.

The goal is to get the side that’s dragging pulled back in a little, lubed up on the mechanicals and the parking brake cable adjusted evenly from left to right.

Keep in mind after adjustment the cables may show one side has more adjustment than the other because one parking brake pad is thicker than the other side.

 

[j91z28d1]

if you know for sure the cable lever is against the stop and fully released. the adjuster is full adjusted in. my didn't want to move so I had to take it apart and lube it.

at that point, I'd look at the pad to see where it's rubbing and hit it with the whiz wheel and sand a touch off that spot. it's just a parking brake, they will still hold well.

 

[MrMonte]

Should always replace brake pads in pairs including e-brake pads. The poor quality of new parts these days require "fine tuning" to make work. After verifying show arc & cables are good I would sand down the high spots.