How do I fix a seized brake caliper?
 

I changed my brakes today and the rear drivers side piston is stuck. I couldn't turn it clockwise to push it back in it's bore.
I had to leave the old pad in there because the caliper wouldn't go back on with the new, thicker pad.

I'm going to the junkyard on Saturday to get a new caliper. Will this cause any major problems until then?
How hard is it to replace the rear caliper? Do you just undo the parking brake and brake line? Will I have to bleed the rear brakes? I suck at bleeding brakes and I'm hoping that I can just plug up the brake line when I remove the caliper.

Rebuild or replace caliper- and if that one's so gunked up it's seized, that's not good news for the rest of the braking system...Replacing the caliper assy is fairly straightforward- use the Haynes or FSM if you wish...Bleeding is a snap, too, if you have someone in the driver's seat with long enough legs to reach (my 4 year grabs the steering wheel & shoves his whole body under there to push it, lol)...Crack open the bleeder 1/4 to 1/2 turn, put your finger over the opening (keep pressure on it), and have your assistant push away. After about 15 brake peddle cycles, you'll need to replenish the reservoir. If you replace the caliper, you'll have to bleed via the bottom bleeder screw first, then another set of cycles through the top one...Oh yeh, don't take your finger off of the bleeder 'till you tighten it back down...Also clean up the fluid mess, especially if some hits the rotor...

I looked in the FSM and it says to turn the rear piston counter-clockwise. The Haynes manual says clockwise. Which is correct?

If you're facing the caliper, with the funky-shaped piston towards you, I do believe it's clockwise, but it's been awhile...Make sure you push while you're turning, they can be a PITA sometimes...

I tried turning it clockwise and my needle nose pliers kept slipping and scoring the face of the piston. I'm going to try and do it again tommorrow because I really don't want to replace the caliper. I also couldn't get the caliper off. The passenger side one came off fine, but the driver's side wouldn't slide off the stud.

There is a tool you can buy for this job. It is a little cube that has prongs on it to grip the piston. About 7 bucks and makes itmuch easier

Can you buy that at Pep Boys?

Pep Boys sells one that does the same job, but it looks different. It's a round piece with 2 dimples in it (to fit the recesses in the piston) and a 3/8" drive hole in the center, for your ratchet. Costs about $10.

If it's that tight, get another caliper, either used or rebuilt. Although a PIA, you should see slight movement of the piston with the needle nosed pliers. I have a set in the garage I gave up trying to get the piston out. Have a Snop On set reversed and can barely move the piston.

I bought the cube one from Autozone today. I'm waiting for the brakes to cool before I work on it. Is there a chance that the other brakes could be on too tight? Is there a way to tell? The FSM says to tighten the bolt to 12 ft/lbs of torque but there's no way to get a torque wrench on there. What would happen if that bolt was on too tight?

Put the car in neutral, take off the emergency brake (put a block behind the wheel that's still on the ground so it doesn't roll) and jack up the other wheel - It should turn very easily. If you have to put much effort into turning it, it's probably sticking.

When I bought my car, it came with a seized piston. We rebuilt both the rear calipers, and I used a piston retractor tool I got from the loan-a-tool program at Autozone to get the piston out. I alsot used pliers to rip the old dust boot out, and tried to lubricate the biatch with some brake fluid. That tool worked wonders :thumbup:

The wheel won't rotate at all by hand. I ordered a reman and I'm going to replace it this weekend.

How hard is it to replace the rear driver's side caliper? What all is involved? Is there any tricks I should know about replacing it?

Also the manuals say something about a V spring. Neither of my rear calipers have one. Is that normal? Where can I buy one?

Not hard at all to replace the caliper - I just did the passenger's side on mine.
There's a banjo bolt holding the flexible rubber hose to the caliper. Disconnect that bolt, and the hose comes off. There will be 2 copper washers, one on either side where the hose connected to the caliper, Don't reuse those washers - New ones should come with the new caliper.
Push back (toward the center of the car) the lever on the caliper that holds the end of the parking brake cable, and while holding it back (it's spring-loaded) pull the end of the cable out of the slot in the lever. That gets the cable out.
Remove the lower bolt holding the caliper to the bracket. Swing the caliper upward and then slide it off of its upper pivot by moving it toward the center of the car. That's it - Caliper's off.
The V-spring connects the outter pad to the inner pad on each wheel. It's there to push the pads back slightly when you're not stepping on the brake pedal. They will not come with new brake pads - You'll have to buy them seperately, probably at the Mazda dealer.
Putting on the new calipers is, in the words of all instruction manuals on the earth "Replacement is the opposite of removal." After putting the new caliper on, you'll have to bleed the brakes. Do not over tighten the banjo bolt, but don't under tighten it either. See if you can find the torque spec for it in the manual. When you get the new caliper, MAKE SURE the little metal tube that the bolt bolt goes through is on the new caliper. On the one I bought, it was missing. If it's not there, take out the old one (it'll slide right out) and put it in the new one. That piece has got to be there.

Oops - That line near the bottm should read " the little metal tube that the LOWER bolt goes through..."

Is it necessary to bleed the brakes immediately after replacing the caliper or can it wait a day or two?

Also, is the fluid in the brake line pressurized? Can I take the brake line right off or will fluid spray everywhere?

just buy a rebuilt one

That's what I'm doing. I'm getting a reman from Autozone for $87. It won't be in until Saturday though.

The fluid is not pressurized, but it will leak out. Before disconnecting the flexible hose, put a C-clamp on the hose and tighten it just enough to squeeze the hose together. That'll stop leakage after you disconnect the hose. Leave the clamp on until after the new caliper is on. And you MUST bleed the brakes before you drive the car. If you're not going to drive it, the bleeding can wait as long as you like. I use Castrol LMA fluid, available at Pep Boys. While you've got everything apart, check your brake rotors for grooves. New rear rotors are cheap. I bought mine at a NAPA store for $18.50/each. To remove them, take out the 2 phillips head screws holding them on, and they'll come right off. Those screws may be really in there. A couple hits with a hammer helps to loosen them.

Why can't you drive it before bleeding the brakes? Does that much air really get in there?

Yes, air will enter as soon as the system is opened. There is no possible way to assemble the system without air being present. I would also be cautious about putting a C clamp on the rubber brake hose. It could possibly cause a breakdown of the hose lining. Best to use a rubber plug, or just suspend vertically.
Also make certain that the e brake is adjusted properly. When off, adjust to be sure lever is on stop, or else pads will drag on rotor.

What do you mean by that?


I know air will get in the system, but won't it be o.k. to drive on for two days. I don't like bleeding my brakes and I'm going to take it to a shop to get it done but I won't have a chance until Tuesday.

Hm. Wheels should turn freely without much drag? Suppose I'll be rebuilding my brakes too, once I get the engine rebuilt & in.

The scary thing is I'll actually do it... and spend money on it.

-=Russ=-

No, no, Nope, no way, uh-uh, zip, nada, and no. Do not drive with non-bled brakes.

If there is ANY air in the lines, stepping on the pedal will simply compress the air. Some force will get to the brakes, yes, but air compresses really well, and will simply absorb all the force, your pedal will go to the floor, and you will collide with whatever is in front of you.

-=Russ=-