E-brake issue

[Tleg93]

I was performing a routine rotor and pad replacement this weekend and ran into a small snag. I was having a bitch of a time getting the rotor off. It seemed to come almost all of the way off but the E-brake wouldn't let the rotor come completely off, it seemed to be hanging up. Before anyone says, yes the E-brake was off. A friend suggested that there could be uneven wear causing this to happen. A look at the brake pads confirms there is some uneven wear. There's a noticable groove in the pads and I'm wondering if it could be the same with the E-brake pads. Is there any danger of it becoming a pain in the butt if I just yank the rotors off with force? Is it going to damage something? Thanks in advance.

[vrg3]

Hmm, what exactly do you mean by uneven wear? You mean the inboard and outboard pads had different amounts of wear on them? How would that cause the rotors to stick to the parking brake shoes?

Some brake pads have a channel cut in the middle of them (across the short dimension) to let some air in and to catch debris and stuff; are you sure that's not what you were seeing?

I've never replaced parking brake shoes, but it can't be that hard. And that's all I can imagine you having to do if you gently force the rotors off. I would suggest doing it with a pair of long M8 bolts threaded evenly into the holes in the rotor, since that'll probably be as gentle as it gets.

I wonder if this could be as simple as you just needing to adjust the parking brake or the cable.

[Tleg93]

It could be as simple as as adjusting the parking brake. I was just pressed for time when I started taking it apart and didn't want to get into a 4 to 5 hour job. There's a semi-circular groove on the bottom of the inner pad. I didn't look at the outer pad. It looks like the caliper was crooked and not all the way down on the rotor, like someone took a disc sander and just pressed it down hard halfway up the pad. Bear in mind that I'm not that experienced. I just hope I haven't used the wrong terminology. Fixing the parking brake doesn't seem too hard but I've never done it and neither has the friend who helped me. So, without being sure about what's going on, I opted to wait and ask around here in the meantime.

[legacy92ej22t]

I'm the friend The rotors spun freely when fully on the hub but when we tried to pull them off they would hang up on the pads and then the rotors wouldn't spin. It was almost as if the pads and inside drum part of the rotor were worn at an angle.
The pads were grabbing the rotor and comming out of the drum assembly with the rotor. We tried to gently carress it off with a hammer and that didn't work either. Now I'm sure I could have forced them off but was worried that I'd damage something in the e-brake assembly.

[vrg3]

Heh, Matt, I figured that. =)

A semicircular groove on the bottom of the inner pad... Was the curvature of the arc the same as the curvature of that part of the rotor? Is there a raised circle on the rotor in the same place?

If it looks like the caliper was crooked, maybe it kind of was... The caliper slides along two pins and that's how it's supposed to self-adjust. If it's stuck on one of them, then the pressure in the brake lines might only be able to push the top half of the pad into the rotor or something like that. Is that what it looks like?

Matt, you say the pads were coming out of the drum assembly with the rotor -- you mean the shoes, right? There's supposed to be a retainer or something holding the shoes in.

If there's any way you could get pictures next time you get back to this job, I'd really like to see them to get a better idea of what's happening.

http://www.graphics.cornell.edu/~v/pics/rearbrakes.gif

[Tleg93]

I should say that Matt did most of the work. My job mostly involved losing tools that weren't lost and not jacking the car up correctly.

[vrg3]

Hehe, that's why it's always good to cajole friends into helping you when you work on your car. Last time I did a brake job my friend had to yell "star pattern!" at me every single time I started removing or installing a wheel.

[evolutionmovement]

This happened to me. This is what I did. First I relieved the shoes by turning the nut on the back of the backing plate (check the manual), there's an oblong rubber cover over it and you have to stick a screwdriver in either the top or bottom to loosen the shoes. That having failed, I used the threaded holes to pull the rotor off. When this happened I destroyed the retaining cups for the shoes. This is inevitable that I can tell. Get new ones at the dealer before hand. They are real cheap. I also got the pins that hold the cups on for a few dollars more. They look like a nail with a spade on the end that fitd through a slot in the retaining cup. Reinstalling is a bit of a pain by yourself, so this is what I did. It's difficult to hold the pin aligned and in place while pushing the little cup on against the resistance of the spring. I held the pin with one nahd while using small vise grips locked to the sides of the cup, though pushing an appropriate-sized socket to compress the spring and then turning it 90 deg may also work.

Steve

[ultrasonic]

Brake shoes can wear a groove into the surface they are supposed to contact. The shoe self adjusts to maintain proximity to the contact surface. At some point this can cause the shoe to ride below the level of the unworn part of the contact surface, tending to lock the parts together when you try to take them apart. This is the adjustment that the other Steve (evolutionmovement) is talking about. You should be able to access it from the inboard side of the assembly.

This is common on drum brakes, which is exactly what the parking brake is.

[Tleg93]

Steve, I'll look into doing what you described. It sounds pretty much like I have the problem you describe. The next time I have it apart I'll also look at the caliper pins and see if things may also be getting hung up. Thanks for the tips.

[Tleg93]

Geez, I went to a local Sub dealer and had them tear apart the rear brake assembly. It turns out that there's nothing wrong after all. The e-brake was just having trouble letting go. I watched the tech pry it off as he smiled at me . Fortunately, it only cost me 15 bucks.