I need some help with finding new front brake caliper pistons. I have the stock calipers that need rebuilding, which I purchased the rebuild kit for. I found that 3 of my 8 pistons have a mild etch on their finish that goes around half the diameter of the piston. Are these ok to reuse? If not, where can I find replacement pistons. Mazda no longer supplies them and I did find Centric makes a replacement that is either hard to find or no longer made. The number is CENTRIC 14636010. Any help is appreciated. Does Carlson make a replacement?

Mike

Also, I did considered just getting remanufactured calipers, but mine are already painted and are otherwise in very good shape.

 

Well you could just buy a set of used stock calipers and remove the pistons. You could find a set for cheap if you're not in a hurry...that might be the most cost effective route considering you don't want to repaint calipers. And its always good to have some spare parts laying around

How bad are the pistons?

As I understand the seal occurs where the o-ring meets the piston, so as long as that area of contact is ok, your brakes should be fine, right? In other words: would the scratched area ever encounter the o-ring seal while the piston is traveling in and out?

I'm no expert on brakes and really don't know what the criteria is for reusing or replacing pistons, I know people that are very picky when it comes to brakes (obviously its a safety issue) and then again I've seen people run brakes that in my opinion should be thrown away...

 

Try 800 grit or higher sandpaper, may just be a stain. If it wasn't leaking before, it probably won't now. Use scotch bright pad if worried about sandpaper. Even if you can't get the scratch completely out, just make sure it's smooth. Also check price of FC front calipers, they're probably cheaper and use the pistons out of it. I say that with slight hesitation because I've never actually interchanged them but I do interchange pads and caliper rebuild kits between the two.

 

Update:

Centric no longer sells the piston replacements. Therefore, to my knowledge, new pistons are not an option anymore for any of us.

I will try to lightly sand the etching to see if it comes out. The pistons did not leak before I took the calipers off. I also found out that the Mazda piston replacements, when they were still available, did indeed fit all the front calipers for the 2nd gen through the 3rd or from 86-95. I did buy two used '91 front calipers yesterday and will see if they are interchangeable and will let everyone know what I find out.

Mike

 

If you have already sanded, then disregard. I used a rag and valve grinding compound. After a hand-buffing, all was mirror-finished. Try that.

 

I haven't tried sanding yet. I was waiting for the old '91 used calipers to come in to see what shape they are in. Thanks for the advice. If I need to polish any, I will try the valve grinding polish.
Mike