Brake caliper rebuild(RX-7 content)

Hey guys,

A friend of mine is the original owner of a nice 89 RX-7 Turbo II. It is not used much anymore, but he wants to use it more. It's not perfect, but still very nice. He has asked me to do some repairs to it. Number one is one of the rear brakes is hanging up. He brought it to my house yesterday, and I noticed the drivers side rear wheel was very warm after sitting in the driveway for at least 5 minutes or so. We also noticed the rotor on the corner was looking pretty rough and grooved. I think it needs a new rotor at a minimum. I was thinking I could rebuild the caliper, but I have never done this before. How hard is it? Worth attempting, or just get a replacement? Should I just replace the one rotor, or do both sides? Should I replace all of the rear brake pads?

Also he has a problem with the power steering that I have to figure out. He mentioned that the wipers only work on setting 1, and not the intermittent or high setting? Typical second gen cold solder joint, bad switch, or other type of failing? He didn't ask me to fix that, but if I can I will.

I rebuilt calipers on my old RX-2. Not a bad job really. Success will hinge on the condition of the caliper bores and pistons. Light corrosion can be cleaned up with emery cloth. Deep pitting will obviously cause problems.

Thanks for reminding me. I've had the parts sitting on a shelf in the garage for maybe five years now. Front calipers have been lightly dragging for that long. Car is coincidentally a 1988 Mazda RX-7 Turbo II.

I'd just redo the whole system, lines/pads/rotors, and rebuild all 4 calipers with OEM Mazda parts.

But then I like to go overkill.

It could just be the caliper slides (im unfamiliar with rx7 so maybe it uses a different method, but I would guess it has slides). I know they can get gummed up, especially if you lose the dust caps, and then one pad stays squeezed to the rotor, even when not breaking.

Just remove the slides, clean them up, and re-grease them.

If you have piston rust or stuck piston or something, I just go for entire new calipers, since the cost is still quite cheap in my mind. (what, like 30-50 per corner after core?). No use in my mind worrying about the quality of my brakes.

I'd probably consider z31's approach, especially if the car hasn't been driven much for quite a while. That's probably a $500 endeavor for all the parts? Maybe less?

My recent experience with new aftermarket brake parts would lead me to choose a caliper rebuild with Mazda parts as the preferred alternative.

1988RedT2 wrote: My recent experience with new aftermarket brake parts would lead me to choose a caliper rebuild with Mazda parts as the preferred alternative.

It's almost like that was mentioned just a few posts ago.

If it's a sliding caliper, the rebuild should be pretty easy. IIRC the fronts on these are 4 pot non-sliding so they're going to be harder to rebuild as you may have to split the caliper to get the pistons out.

However before I would tear into the caliper I'd check that it is indeed a stuck caliper and not a bad brake line acting as a one way valve.

The rear caliper can be trickier to rebuild thanks to the automatically adjusting piston and parking brake. The piston needs to be screwed in to compress. Although some of the parts store sourced calipers can be questionable sometimes, I don't know if Mazda has any OEM left for this car. They tend to use much better quality pistons and seals. The parts store sourced rebuild kits often have issues with the seals not fitting correctly and mediocre pistons.

Diagnose first.

If you are going to replace one rotor, might as well replace the pair and pads also - esp if one was worn oddly.

Do you guys know if the turbo II uses 4 piston calipers in the rear as well as the front? I seem to remember that the turbo had upgraded brakes over the N/A cars. Maybe it's just the fronts.

4 piston up front only.

for the second gen you had rear brake options for solid disk or vented disk. This makes a difference in terms of getting a reman caliper but I believe the seal/rebuild kits are the same.

regardless they are super simple to rebuild permitting you can get them apart and they the piston inst seized.

All - ALL - RX-7 rear calipers have the same internal dimensions. '81 GSL to '95 FD. So that's no big.

All 5 lug FC fronts were 4 piston, same internals as FD and some other vehicles too. Sticking pistons is common with them, never tore one apart to find out why. Given my experiences with the single piston calipers, the problem is probably the piston rusted under the boot and locked itself to the caliper. Don't know what havoc this wreaks on an aluminum caliper body.