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Tony Sestito
Tony Sestito PowerDork
3/9/20 8:59 a.m.

I just discovered yesterday that my daily driver 2012 Mazda 3 has a case of the piddles. Specifically, it's leaking brake fluid.

The rear driver's side caliper is leaking out of where the e-brake bracket mounts to the caliper. The piston seal is still fine; it's just the top seal that's under the bracket that's leaking. It's $10 for the seal kit vs over $100 locally for a remanufactured caliper. If I order online, I have to deal with the hassle of shipping back the core and all that, and it's not much cheaper than locally buying one. Been there, done that, didn't end well.

Am I dumb for considering just replacing the seal and saving $100? I've always just gotten new calipers when stuff like this happens, but how hard can this be? Does anyone actually do this anymore?

CAinCA New Reader
3/9/20 9:14 a.m.

I haven't ever needed to rebuild a caliper but I wouldn't hesitate to rebuild that one. It seems like an easy decision to me. 

Professor_Brap Dork
3/9/20 9:16 a.m.

I always rebuild. I have had terrible luck with remans. Also they take like 30min to rebuild. 

spandak HalfDork
3/9/20 9:35 a.m.

Where does one source seals for rebuilding calipers? Never done, never needed to, but it's bound to happen one day. 

Tony Sestito
Tony Sestito PowerDork
3/9/20 9:39 a.m.

In reply to spandak :

Rock Auto and Amazon had them. I just ordered two sets from Amazon.

Professor_Brap Dork
3/9/20 10:15 a.m.

In reply to spandak :

Also most part stores can get them

outasite HalfDork
3/9/20 10:24 a.m.


As an auto tech instructor for over 30 years and mechanic since 65, I have rebuilt/supervised the rebuilding of hundreds of calipers. I usually replace the piston as well (MN salt/rust issues). 

wspohn Dork
3/9/20 10:30 a.m.

Whatever you do, pay attention to the condition of the sealing surfaces. If the piston(s) are pitted the rebuild is unlikely to be a long lasting one. 

Some calipers require a retracting tool - don't know if yours is one of them.

Tony Sestito
Tony Sestito PowerDork
3/9/20 10:32 a.m.

In reply to wspohn :

When you say " retracting tool", do you mean the tool to spin the piston in? I have that.

iceracer MegaDork
3/9/20 10:33 a.m.

If I found the need, I would.

Cousin_Eddie Dork
3/9/20 11:03 a.m.

Yes. Always. It's a straightforward job to do and saves you mad coin. The only time I'd buy a reman is if my core had a fatal flaw that I couldn't overcome. 

Curtis73 MegaDork
3/9/20 11:45 a.m.

I did one.  Mine had disastrous results because I honed too far and I couldn't get the piston to seal.  Oh well, lesson learned.

Remans often suck.  They usually pull them apart, media blast, and re-assemble.  Many of them don't even really hone the bore, so they don't last long if they don't leak right away.

Tony Sestito
Tony Sestito PowerDork
3/9/20 12:13 p.m.

I'm struggling to find a good tutorial on how to do this. From what I'm seeing, I'm going to have to completely disassemble the whole thing just to replace the e-brake lever seal. I was hoping to be able to sneak that seal in without having to remove the main piston and all of the internal bits. Is this normal?

Toyman01 MegaDork
3/9/20 1:09 p.m.

I've rebuilt them before, but not in a long time. Remans are cheap enough that I just swap them out. I've also never had a reman fail. If I had I might change my mind.


Knurled. MegaDork
3/9/20 1:10 p.m.

In reply to Tony Sestito :

The seal is going to be sitting in a groove, so yes complete disassembly is mandatory.

ebelements Reader
3/9/20 1:37 p.m.

I'm probably going to lose my car guy credentials, but I have never rebuilt a caliper. Most of the vehicles I've needed to pull a caliper off of were so rusty or trashed that it always just made sense to grab a reman unit. Now, most of those calipers were 35-60 bucks, so the possible savings weren't all that substantial. If I lived in a less rust-prone area (or owned cars that had more expensive calipers) I'm sure it would be a different story.

Knurled. MegaDork
3/9/20 1:44 p.m.

In reply to ebelements :

I've rebuilt (usually reusing the old seal, just cleaning the rust off the piston so it could be pushed back), I've bought reman, it is what it is.  Rears I have never rebuilt because 99% of the time the piston is faulty, and replacement pistons usually cost as much or more than just buying a reman.

The0retical UberDork
3/9/20 2:00 p.m.

I've rebuilt the Vibes rear calipers and the X-Terras fronts. Super easy.


I'm not sure what the story has been lately, but I've been getting absolute E36 M3 reman parts from just about every supplier I've ordered from for the last year or so. I've reached the point where I may as well do it myself with junkyard parts and save the hassle of doing the job twice.

Tony Sestito
Tony Sestito PowerDork
3/9/20 2:43 p.m.

I'm going to give rebuilding a shot, provided I can find a tutorial. Again, this is just the top seal, not the piston seal, so if there's any way to do it without pulling the whole deal apart, that would be great. I've never rebuilt, either.

If it doesn't work out, at least one local parts store has a caliper, and there are a few junkyards that have some low mileage examples as well.

Knurled. MegaDork
3/9/20 3:33 p.m.

In reply to Tony Sestito :

The bit that sticks out the back of the caliper IS the piston.  There's a ratcheting mechanism inside that allows the piston to get "longer", which is the reason you have to thread the piston in when you want to retract it.


Unless that arm is exposed to fluid, in which case, the cam that pushes on the ratcheting mechanism is internal and not external, so you probably have to have the piston out to get the internal cam out.

dean1484 MegaDork
3/9/20 3:49 p.m.

I have not done it in years but yes they are easy to rebuild just pay attention to the condition of things.  

Streetwiseguy MegaDork
3/9/20 3:53 p.m.

The park brake style like yours are fiddly.  The shaft will be rusty down near the seal, so there will be some polishing required.  Too many pits on the piston will be trouble, too.

iceracer MegaDork
3/9/20 6:02 p.m.

When you get it all together and back on the car, don't forget the adjust the piston with that tool you used to retract it.

Takes a lot of pumps to do it hydraulically.

irish44j MegaDork
3/9/20 7:10 p.m.

I usually rebuild. One exception was the Sequioa 4-pots since Raybestos makes brand-new calipers for cheap with no core charge (directly using the original Toyota casting design, patent must have run out). Hardly cost any more than a rebuild kit. 

Tony Sestito
Tony Sestito PowerDork
3/9/20 7:20 p.m.

Ok, I checked out my service manual, and it says absolutely nothing about the parking brake assembly on the caliper. Removing the piston is straightforward, but it says nothing about that parking brake arm. Either the seals are behind the piston, or it's not serviceable. The kit comes with two sets of seals: one set for the large piston, and a smaller set.

I'm leaning toward just clicking the easy button and getting new or remanufactured ones. frown

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