Caliper Rebuild?
 

Has anyone rebuilt one of the front brake calipers? How hard is it?

You can buy a caliper rebuild kit for about $40.

New caliper costs $420, used caliper costs $170.


I've had one front caliper fail (piston siezed up) and the other one will probably go eventually so I'd like to rebuild it if it isn't too hard to do.

Wow, what timing lol.


I just, this weekend took on this endeavor. Something to think about, if you had one fail chances are the 2nd isn’t far behind. In my case, living in Germany for a year wreaked havoc on everything on the car (mainly the extreme amounts of salt used on the roads). The outside of the caliper piston had the surface marred with pits from salt/debris. Anyway, here is what I ended up needing...

Old Caliper
Brake Cleaner, In my case I used 2 bottles of the stuff, one on each caliper... love it
Caliper Rebuild Kit (Kits have parts to rebuild 2 front OR 2 back)
Steel Wool
Something to cover your brake lines with ( I used sandwich bags and rubber bands)
DOT3 or DOT4** brake fluid (DOT3 is stock, I use DOT4**, higher boiling point)
Air Compressor, ya air compressor.
Brake disassembly/reassembly Instructions and Bleeding Procedure


You can download the Mazda Instructions @ http://atomixcomputers.net/misc/Rx8/Disc.pdf

Removal is pretty strait forward, once you get the brake line off make sure you cover it (sandwich bag and rubber band or twist tie works well) and then you can shove it up near the top of your strut (so fluid doesn’t leak out).

You can see from the diagram on page 18, only 2 bolts (#2) need to be removed for the caliper to come off.

With the Caliper off use compressed air where the brake line connected to force the piston out of the caliper

***NOTE*** USE SHORT CONTROLED BURTS OF AIR, PISTON CAN SHOOT OUT AND CAUSE SERIOUS INJURY IF YOU DONT PAY ATTENTION

ya I shot it out pretty fast

When you get the piston out pay VERY CLOSE ATTENTION to how the seals are coming off. Now inspect the piston and the caliper very carefully, if the shiny surface of the piston (below the lip) is pitted/rusted at all, you need to replace the piston. If the inside of the caliper is pitted rusted at all, you need to replace the caliper (cant rebuild)

Use steel wool to remove any rust around the lip of the piston and around the lip of the caliper.

Seals... this was the biggest pain in the ass I’ve ever endured. If you’re doing this yourself be sure to only do one at a time (so you can refer to the other while rebuilding.

After reseating the piston, reinstall calipers (making sure the bleeder port is on the top, ya I put em on upside down and wondered why I couldn’t bleed the brakes, HEY it’s easy to do, don’t judge me! lol)

Hook the brake lines back up, bleed brakes and done yay


If for some reason you do need to replace the whole caliper... I found that O'Reilly's/Checkers/Schuck's/Kragen and Murray's have a contract with a company called Cardone. They are the only ones that I know of that rebuild OEM Rx8 Calipers
and they are $90 for the FRONT and $160 for the REAR.

**NOTE** As of this post they did not have any in stock which means you bring your calipers to one of the above stores and they send them to CarDone and you get your rebuilt/cleaned parts back

Hope this helps.
Matt

Thanks for the detailed write-up.

Does the caliper rebuild kit come with pistons? I may need to replace mine.

This weekend I installed a used caliper to replace the one that seized up. Kind of a PIA but glad to have the car back on the road.

Nope..just the seals and dust boots

Aye, you will actually be stunned with you see what $40 buys you lol.. but hey... gotta pay to play right?

included in the Rebuild Kit...

2x Bleeder Valve cover boots
2x Caliper to Wheel Boots (and supplied greese to fill them with)
2x Internal Piston Seals
2x Piston boots


thats it, all rubber.... weighs less than 4oz


I did end up replacing my whole caliper because of the pistons, bought a set of used ones off ebay (was impatient) for 90$ shipped. Then I rebuilt those and installed. You prolly can buy new pistons.. .but the way mazda charges Id hate to see what those go for.

So having melted the piston boots on my front calipers I am now trying to decide which option to go for:

1. NuGeon-QBR (OE Rebuilt) calipers: 61.33 per side. Free shipping, but I guess I'll have to pay ~15 shipping for my old calipers to get the core deposit back.
2. Mazda Caliper rebuild kit: ~50 once I pay for shipping
3. Dorman Caliper repair kit: 4.88 +12 shipping, and I think I need 2 of these, so 22 all in.

Hmmm, never rebuilt a caliper before, need to do it in a weekend, but will save ~115 if I do it myself with the Dorman repair kit.

Time for an upgrade :suspect:

So I went with option 3. Spent a while trying different approaches to getting both ends of the caliper dust boot hooked up before googling for my answer. Found it here: I had actually tried it that way, but without the brake fluid as lubrication. With that, and the confidence this way would work, it took me just 5 minutes to get the dust boot on one side, with the caliper still on the car :) The other side was not so easy, for some reason it really did not want to sit in the caliper and took me at least 30 minutes of swearing to get it in. I suspect the rubber piece was not quite right shape and will be trying the oem mazda kit next time...

Overall, worth the savings over buying rebuilt calipers. Since you can replace the dust boot with the caliper on the car, I think the effort is probably similar to replacing the whole caliper once you get the knack of sliding the dust boot into place.

The doorman kit includes the dust boot and caliper seal for one side. So, you do need one kit per side, and it does not include the rubber pieces or any grease for the guide pins so you need to buy the mazda oem kit those need replacing.

A few tips for others doing this:

1. Don't follow the part in the video of using your hand to catch the piston as you blow it out. Use a block of wood, or just a cloth and use goggles. If you mis-judge the air pressure you will shoot the piston and a spray of brake fluid out at high speed! I used a foot pump with an air-bed/inflatable toy adapter and took my time with this to not over pressurize the piston.
   
2. Gently wiggle and push the piston in once you have the dust boot seated. On the 2nd side mine did not want to go in so I had the smart idea of using a caliper compressor on it. Well that resulted in the cylinder cutting through the new piston seal :(
   
3. Be careful not to over tighten speed bleeders in the front calipers. Fortunately the trick on the speed bleeder website of using a hex wrench (allen key) worked to get the broken speed bleeder out of my caliper - see part way down this page www.speedbleeder.com/News.htm. The rears use a much bigger thread, so much less likely to happen there.
   
4. For the track folks, it is likely just the dust boot that needs replacing. My caliper seals were in good condition and I re-used one side after tearing my new one(see 1 above). Guide pin covers are OK, but hardened a little.
   
5. For replacing rear pads after a track event, peel the dust boot free all around the edge before trying to rotate the piston into the caliper. You don't want the dust boot to stretch itself trying to rotate with the piston.
   
6. Finally, if you don't want to do this after every track weekend, take the time to cool your brakes after a run. My experience is the calipers get hottest due to heat soak from the rotors and pads after you stop.
   

So it turns out using the Dorman Caliper repair kit was a bad idea and I would strongly recommend against using it...

Having fit it all, it appeared to work fine on the street for a few weeks. However, hard use of the brakes on track resulted in a leaking caliper and a sinking brake pedal.

Compared to the oem replacement I bought, it was a poor fit for the calipers on my s2. The inner seal is slightly undersized, eventually allowing fluid to leak past. The outer seal is slightly oversized, making it difficult to fit.

The ease of fitting the oem outer seal in comparison is alone is worth the difference in cost. As for the inner seal, I would suggest putting that to some use other than as a seal in your RX8 brake calipers.

Napa sells re manufactured ones for $90

I have a pair of OE Mazda rear caliper rebuild kits if anyone is interested. Got stuck for time and just ordered a rebuilt pair of rear calipers instead of rebuilding my original ones.

Some of the rebuilt calipers are fitted with polymer pistons to keep cost down, you have to be careful about the really cheap ones if you intend to run the brakes hard i.e. track etc.

Also, a Speedbleeder doesn't accomplish anything more than you can already do with the OE bleed screw for one-person brake flushing. I've posted the procedure numerous times on the forum.


.

Ill take that off your hands Team... :Freak_ani

sounds like the dorman kit isn't metric

Damn, I have front caliper that's getting replaced this weekend but I'm just getting a reman. I'm not sure where you're getting your prices but I payed $35 with a $55 core charge so it ended up costing me $90 but i'll be getting back $55 when I return the core.

Definitely not worth the hassle, at least for me, with prices like that to rebuild it.

RockAuto Parts Catalog

Im in Canada and I had to replace both my rear calipers, discs and pads. Dealer quoted me 365 for each caliper. I said nevermind, went to a Canadian tire store (which would be equivalent to autozone in the USA I guess) and I got them for 213$ a piece with a warranty. Bought my own slotted discs and ceramic pads off ebay. Total cost for calipers+discs+pads= 540$.

I suggest you go to your local parts store, ask them to shop around parts warehouses they can get you a good deal. Better than to rebuild yourself, it could be dangerous if they fail again

That is unbelievably cheap. Still not as cheap as rebuilding using the oem seals though :-)
The reality is those calipers don't have metal cylinders, and I would guess are not using oem seals either. Probably fine for the street, but I'm not going to be the one to test them on the track...

It is pretty obvious that for me, rebuilding using the oem seals is the way to go. $50 delivered for the front two. Now that I know how, the time and risk is the same or lower than replacing the calipers. I can do one in under 30 minutes. I don't have to remove the caliper from the car to rebuild it and I end up with oem piston, caliper and seals. I can also pack a spare set of seals in a much smaller space without needing the core charge of complete replacement calipers.

My piston and caliper are in good condition. I am just going through dust boots with the heat on the track. If a piston or caliper is damaged, corrosion or otherwise, then a rebuilt one might be the way to go.

the piston isn't available from Mazda separately, but it is just a sumitomo caliper, that doesn't look that special, so i would imagine caliper pistons are available somewhere, just not from Mazda

Rebuild Kit Wanted After Powder Coating Calipers
 

So Im powder coating my calipers soon and need a full set of rebuild kits. Ive never done something like this before, so any guidance or tips beyond where I can purchases the rebuild kits, would be greatly appreciated!

My local Autozone sais they used to carry rebuild kits for the rear calipers however it only included rubber and metal rings which seems to be less than a complete kit.

Thank you in advance for your help@

You can buy the rebuilt kits from several different online Mazda dealers. You need 1 for the front and 1 for the rear. These kits only include the piston seals, dust boots, bleeder covers, and grease packets. Incidentally, the grease packets are not labeled, so I guess you are just supposed to know what pink and purple greases are for.

For example:

2010 Mazda RX-8 FRONT BRAKE MECHANISMS

If you need new pistons, Rock Auto sells Centric pistons, but they are fairly expensive at $11 each front and $26 each rear.

I used to rebuild calipers years ago.
Kind of a PITA.
I find that calipers are so cheap now it doesn't pay to spend the time to rebuild them.

Meh. It takes me 10 minutes each. Once you get the hang of it, it goes quickly.

What brand remans are you using?

Thank you very much for your info and reply! So 1 front kit contains everything to redo both fronts? And Im not using anything remans, Im using my stock calipers and powder coating them a gloss red.

I bought one from rock auto and returned my oem seized one for core costs. Was pretty cheap (sub $70).

Sorry. I meant to address that question to BigCajun. Just trying to establish which remans are the good ones (no plastic pistons).

I thought you were addressing him too.:)
I get most of my aftermarket parts from Advance, with the internet coupons, you can get some pretty good deals.
I didn't get calipers, but I got all 4 rotors & pads.
Also got my first set of coils, wires & plugs, and recently a new fuel pump from them.