I've done many searches and couldn't find a satisfactory answer. One of my emergency brake mechanisms in the rear calipers is not pushing the pads against the disk. One side works and the other side doesn't. I've disconnected the cables at the calipers and activated the e brake levers by hand. The driver side grips the disk while the passenger side does nothing for the same amount of rotation of the lever. Even if I apply more rotation to the passenger side, I still get no push against the disk. My shop manual just shows a shaft going into the caliper without any explanation as to how the mechanism works. Any comments would be appreciated. Please note that the cables, interior lever, and adjustments are fine.

Babbs
1988 base model, 4 bolt hubs.

 

When the mechanism rotates, the base of that shaft with the nut on it is beveled, so that when the shaft turns, it pushes up on the pin that sits in it.

When the pin is pushed in, the entire assembly (adjusting rod and piston) is pushed out - applying pressure on the rotor. The interesting thing is that there is no twisting motion of the piston as there is when you hit the brake pedal... the whole assembly moves.

I just rebuilt my rears yesterday... pretty good stuff!

 

Rebuild your calipers... its cheap ($36) and its probably time to do it anyway!

 

Thanks for the info. It's beginning to make more sense. It sounds like the whole assembly is seized in the activation position. Rotating the lever/arm does nothing as the assembly doesn't return back to its normal position. Dynamic braking seems normal which is surprising. I'll tear the calipers apart and see.

Babbs.

 

Um, just a heads up, i tried to pull mine apart a few months ago, it was such a pain in the *** i gave up and bought new calipers. If they are as corroded as mine you have no hope of getting the pin out of the caliper that is supposed to pivot without cutting it out. you will spend about 120 on new calipers.

 

I appreciate your comment. When you talk about the pin, do you mean the pin/bolt/nut? that the spring wraps around? Or is it something internal to the caliper?

 

where are you guys getting rebuild kits and do they come with the parking brake bearing? I have a hanging caliper but cant find anything that comes with the bearing...

 

Mazdatrix.

Didn't come with the bearing... but it didn't need it anyway. My caliper was sticking too... so I ordered that seal kit, and it fixed all my problems. I've never rebuilt a caliper, and I thought these were actually pretty easy. I think I can do one in about 30 minutes including cleaning time.

 

And the trick to getting the "pin" (adjusting rod?) out, leave the piston screwed onto it about a half turn, then use needle nose pliers to pry up on the spot where the inside of the boot sits, it'll come out.

 

Once again, thanks for all the tips. I have the rebuild kit and I'm just trying to find the time to do it.

 

Referring to the combo that holds the spring in. if its not corroded too badly you have a chance.

 

I finally got around to taking the calipers off and after some cleaning up and some back and forth movement of the activation shaft both sides move freely. The piston assembly moves smoothly out and the spring pulls things back in. Because of the descriptions that I got here, I could visualize what was going on internally with the ebrake. Thanks again for all the comments. This site is one hella good resource.

Babbs

 

Awesome. Good to hear!