Hi all,

I started doing a check of my parking brake prompted by it not holding my truck on small inclines. This is important as I use this truck to launch my boat and I want a working parking brake. I figured that the problem was that the the cable might have stretched a bit and/or the self-adjusters on the parking brake shoes were not working properly. I've had to do this adjustment several years ago.

But when I got to the parking brake shoes and the drum surface on the inside of the rear rotors I saw what I think is perhaps the cause of the lack of holding; the drum surface is no longer smooth. It isn't pitted but has low little mounds of rust on there surface. FYI, I'm pretty sure the parking brake mechanism and drums did not get wet when launching since I have a long enough tongue on my trailer that the treads of the rear tires only have to just touch the water to launch my boat.

Also one of the shoes has lost a small amount of material on the outside edge. (see pics)

My question is could the surface of the drums be the culprit in the brakes not holding as they should? Is it reasonable to have them resurfaced?

Any other thoughts?


Shoe; LF This shoe looks fine to me.


Shoe: LR, note loss of material on the shoe


Left rotor Note the surface of the drum


Shoe, RR This shoe looks fine to me also.


Right rotor Note the surface of the drum.

 

I'm not an expert by any means, but if it were me I would start with the parking brake adjusters. The drums could be cleaned with a wire brush and the shoes that are failing could be replaced.

Failing that, you might look at replacing the drums, to me resurfacing seems like a last resort. It seems to me the shoes should hold even though the surface is poor.

 

I would lightly scuff drum surface just to remove surface rust with emery cloth or sandpaper . Machining them just increases the diameter and then they get close to the outer limits of the adjusters in order to work . The further the circular parking brake shoe expands the less contact it has with drum because it distorts as a circle . If you do machine them just remove any high spots don’t want to remove more metal than necessary since they just need to wedge tight against shoes to hold good and aren’t used to stop .
The parking brake shoes could be scuffed also just to break the glaze off , but I’d be tempted to just replace them since it’s easy now that all apart. Be sure all pivot points are clean and lubed . Then adjust parking brake tight with rotor/drum on to center shoes and back adjuster off until just barely no drag .
Then if pedal isn’t tight halfway through its travel do parking brake cable adjustment .