Hi, despite my best efforts I just cannot get my parking brake to hold on a hill, seems worse facing downhill than up. The shoes are not new but have just over 2mm of friction material left on them, which I consider should be plenty? I have followed my GM manual to the letter where I back of the cable adjuster, then adjust the shoes until I can only just get the rotor/drum back on, followed by adjusting the cable again.
Am I being stupid & missing something obvious here?
Any suggestions would be appreciated as I really need the parking brake to work properly, as I regularly have to park on steep hills so it makes it difficult getting the transmission out of park when the parking brake isn't doing it's job?

 

You mention adjusting the parking brake cable...but are you adjusting the shoes after drum is back on? By going through the slot on the back side of the backing plate. Using an adjuster or screwdriver to rotate the little wheel on the actuation mechanism? Take a look at the pic...the part you need to adjust is the brass colored pieces in the top row. Basically the same concept as old drum brake adjusters



Adjusters should be adjusted prior to adjusting the cable (say that 3 times fast . Adjusted until you start feel a slight drag, then adjust your cable. (On a '98 Blazer anyway)

 

I had a similar issue on my truck. When you have the rotor and brake shoe removed, inspect the actuating cam/piston assembly for movement. Mine were rusted solid and would not expand the shoe.

Cleaned and lubed everything. Now the parking brake works great!

Cheers,
Joe

 

I have never noticed a hole in the backing plate where the adjuster can be accessed - will have a look. I have stripped & lubed the actuators, they move fine. Will keep you posted. I don't know what the wear limit is for the friction material? Mine has about 2mm left which I would have thought is OK - correct me if i'm wrong?

 

I took a look in the TSM I have handy sitting next to me (97 Blazer) and I could not locate any minimum thickness for the lining. I'm guessing as long as it has some friction material on it and it holds the truck still, it should be good to go.

To access the adjusting wheel I'm pretty sure you have to get to it using the same slot that the lever sticks out of. My recommendation is that you disconnect the cable (or loosen it so there is slack in it). Pull the wheels back off. Pull the rotors back off. Then turn the adjusting nuts until you can just get the rotors back on. This way you can see the adjusting nut and get a feel for how it rotates before your trying to adjust kind of "blind". Then put the wheels back on

Then from the backside of the backing plate access the adjusting nut and adjust it until "...the rear wheel will not rotate without excessive force in a forward direction." (that is a correction to my previous post...however with only 2mm left, you may not want to stop just short of the ("excessive force" mark). Once you have done that on both wheels..then adjust your parking brake cable.

 

Well, despite looking in my GM manual & also enquiring online I could not find ANY information on minimum lining thickness for the parking brake shoes. So - I phoned the (only one in the UK) main GM dealer that still deals with the Blazer & was told that 2mm should be enough but if the drums/rotors are worn enough then the shoes still may not hold the vehicle on a hill. Rotors are new so they should not be a problem.
Anyway, I ended up ordering a new set of Raybestos shoes (GM ones were a stupid price), fitted & adjusted them & parking brake couldn't be better now.
Problem solved, with the benefit of hindsight I should have just bought new shoes when I bought the rotors but thought at the time that there was enough lining left on the shoes to last for a while yet?

 

Thanks for the follow-up.

 

No problem - out of interest, where abouts are you in PA? I have visited a friend in PA several times when i've been in the US. He lives in south-central PA about 25 miles east of Johnstown. Nice part of the country.

 

to adjust drum brakes, put it in reverse, start moving, and slam on the brakes, That is how its done on most.

 

I'm north of Harrisburg.