Snowdoggie
Snowdoggie Reader
2/2/09 9:27 a.m.

Do I have to replace the rear caliper on the other side too. A mechanic friend told me I had to replace them in pairs to balance the hydraulic pressure.

AngryCorvair
AngryCorvair GRM+ Memberand Dork
2/2/09 9:51 a.m.

did it fail catastrophically or is it just worn out from mileage? if you're really broke or if it failed in a not-normal way, then I'd be OK just replacing one. But if it's worn out because it's got 200k on it and has never had the fluid changed, then I either rebuild or replace in pairs.

i don't understand your mechanic friend's comment. "balance the hydraulic pressure" makes no sense to me. calipers receive pressure from the master cylinder, and that pressure acts upon the piston area to generate a clamping force, which is applied through the pads onto the rotor.

perhaps he means that the new caliper will be more efficient at converting pressure to force, which could be true if the old caliper has boogered-up slide pins.

Snowdoggie
Snowdoggie Reader
2/2/09 10:56 a.m.
AngryCorvair wrote: did it fail catastrophically or is it just worn out from mileage? if you're really broke or if it failed in a not-normal way, then I'd be OK just replacing one. But if it's worn out because it's got 200k on it and has never had the fluid changed, then I either rebuild or replace in pairs. i don't understand your mechanic friend's comment. "balance the hydraulic pressure" makes no sense to me. calipers receive pressure from the master cylinder, and that pressure acts upon the piston area to generate a clamping force, which is applied through the pads onto the rotor. perhaps he means that the new caliper will be more efficient at converting pressure to force, which could be true if the old caliper has boogered-up slide pins.

It's got about 140K on it and the piston has seized. Probably worn out by mileage. I am going through the car and the brakes are next on the list. Everything else I replaced so far has been worn out. The shocks were a mess. Radiator had to be replaced, along with the water pump, timing belt and so on. I would imagine the brake fluid hasn't been changed in a while if it has been changed at all.

Kramer
Kramer Reader
2/2/09 12:59 p.m.

It wouldn't hurt to replace both, as you don't know the exact condition of the opposite caliper. It's relatively inexpensive, and since you're already doing the work...

I've replaced paired-items one-at-a-time, and usually it's okay. Sometimes not. Your call.

iceracer
iceracer Reader
2/2/09 1:06 p.m.

You pretty much answered your own question. You are going through the car, replacing worn parts. Both calipers.

Snowdoggie
Snowdoggie Reader
2/2/09 1:08 p.m.
iceracer wrote: You pretty much answered your own question. You are going through the car, replacing worn parts. Both calipers.

At this rate it won't be long until I replace the entire car, piece by piece.

93celicaGT2
93celicaGT2 HalfDork
2/2/09 1:13 p.m.

^Some consider that just part of the fun!

Whenever my car doesn't start, i just go back and think to myself... "Now what have i NOT replaced?" and go from there. Makes things easy.

Keith
Keith GRM+ Memberand SuperDork
2/2/09 1:22 p.m.

I'll bet it isn't a siezed piston, but a siezed slider pin. The passenger's side, right?

Pull the other caliper off, check the condition of the pin. If it's corroded, you can either sand it smooth or replace it with a new one from Mazda. Reinstall with some nice brake lubricant such as Syl-glide.

racerfink
racerfink New Reader
2/3/09 9:13 p.m.

I would bet on the rear slide pin on the passenger side as well. I've had to replace that caliper on both the street car and the race car, both because of bent pins.

RotorNutFD3S
RotorNutFD3S None
2/3/09 10:04 p.m.

I'm glad I found this thread, my passenger side won't release unless I go around and release it by hand at the caliper. Now I can try a fix before I try to replace it. Thanks.

Keith
Keith GRM+ Memberand SuperDork
2/3/09 10:10 p.m.

That's a slightly different problem, but also solved with lubrication.

RotorNutFD3S
RotorNutFD3S New Reader
2/3/09 10:22 p.m.

Hmm... lubrication and multiple attempts with pb blaster to unfreeze it to make it work normally have failed. Maybe this is one of those times where replacement is necessary.

aussiesmg
aussiesmg SuperDork
5/5/11 8:38 p.m.

canoe freak

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