Originally Posted by Douglas
Car question, not sure where else to ask it.
I recently had my rear brakes replaced and was a bit irritated afterwards because the parking brake no longer really worked. When I pulled up on it it went all the way to the top, barely engaged, and parking on any kind of a hill it wasn't enough to hold the car in place. So I'd had to get into the habit of putting the car in gear after parking, which has led to at least 3 or 4 embarrassing incidents where I did my new routine (engage parking brake, clutch in, put car in gear, push "engine stop" button, disengage clutch, remove key) in the wrong order, and just sitting in a spot, clutched out before hitting "engine stop" and lurching the car into an unintentional stall.
However, as of two days ago, all of a sudden the parking brake is dead tight. Two or three clicks in, it engages. It was the "old" way for at least 3 or 4 weeks, then bam, it's like the thing re-set itself.
Anyone ever heard of anything like this?
My first thought is that you should talk to the mechanic who did the job, and see if he can come up with a credible explanation for this.
I'll assume you're not driving one of the few cars that uses calipers for their parking brakes (Ferraris, Audi R8, Lambos, Tesla S), and instead have brake shoes inside your rear rotor that pushes outwards on the inside part of your rear rotor hat. If you look at a rotor as a top hat, the "hat" part is the tall cylinder. Think of action movies where the hero can't stand on the floor, and does the splits pushing against opposite walls of the hallway to stay off the floor. Sorry for the stupid analogy, but that's the only one I can think of right now.
Sometimes when changing rear rotors, the new surface inside will be thicker than the old brakes, because it's new. They have to back off the brake shoes for the parking brake so that the brake engages at whatever number of clicks the manufacturer specifies. They may also change the brake shoes if they're worn. The first case could explain your first few weeks if they had backed off the brake shoes too much, but doesn't explain the reset. The second case may explain the reset because the brake shoes may have needed some sort of break-in, perhaps to wear off some kind of surface treatment used by the manufacturing process. After using it a few times, it may have worn off the new surface of the shoes and given you grip, "resetting" the brakes, but it shouldn't be at 2 or 3 clicks. 5 or 6 is more normal.
If this is the case, the best way to deal with this in the future, besides talking to your mechanic, is to drive around slowly with your parking brake engaged so that you wear off the surface. You shouldn't need to go more than a block (or indeed a few revolutions of the wheels).
There can be more complicated reasons for your problem, but these are the most obvious ones to check first.
Anyway, talk to your mechanic, and he may need to readjust the shoes.