So I have all new drum pads, brake cyl. drums and such on the front for my 69 cutlass. They were doing great but in the past couple of weeks, they seem to be acting a little wonky, nothing to keep me from stopping, but decided to pull off the drum today.

Everything is seated, looks great, but feeling the brake shoes themselves, the back pad feels nice, just like it should, but the front pad is getting worn at the top and bottom but leaving the middle smooth like it should. The wear on the top and the bottom of the one shoe makes me worried, its pretty rough, nothing I am to worried about atm, but what could be causing it to wear in just those two spots? the rear pad of the drum is perfectly fine, and nothing is out of line.

 

A couple of things you need to understand about drum brakes. First, on these brakes, the front shoe is the primary and is known as "self energizing". That means that as the drum rotates and you step on the pedal, the wheel cylinder pushes the top of the front shoe out and it grabs on the inside of the drum. This serves to push the front shoe into the drum, increasing both stopping force and wear. The other thing is that brake shoes are supposed to be arced to match the inside of the drum. That uses a press or bender to change the radius of the shoe to match the ID of the drum. Pretty much no one does this anymore, which is why you get wear at the ends of the shoe but not the middle - the radius doesn't match the drum. This is really a self-correcting problem, since once the friction material wears down, the radius will match. Of course, that means that the edges of the shoe will wear out early, but that's pretty much life these days. Nothing to worry about.

 

oh, i forgot to mention that I don't have the break booster hooked up, does that change anything on the subject? Brake booster took a dump on me after the last master cyl. i installed, so i just plugged it up and am running manual brakes.

 

I saw the same wear pattern on mine when I went to repack the wheel bearings. My brakes work just fine. Joe P. has never steered me wrong

 

The brake booster is irrelevant to shoe wear. Note that if you have the booster disconnected, the brake force at the pedal will be higher than for manual brakes. The pedal ratio is different for manual and power brakes.