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Author Topic: Rear brake caliper rebuild
Mark de Regt Verified Driver Made Donation to Website
Veteran Member

Region: NWR/Oregon; ICSCC
Car #: 70
Year : 1991
Posts: 1111
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Hi,

My last race ended abruptly with the total failure of my right rear caliper; brake pedal to the floor, fluid everywhere, no brakes. [Eek!]

I'm trying to rebuild the offending caliper. The dust boot is not a big problem, but nothing else is obvious.

First, what is the likely cause of the failure? And what's the best way to fix it? Is it as simple as digging the o-ring out, replacing it, putting the piston back in with the dust boot? I have a rebuild kit, but the directions in the shop manual are worthless.

Thanks.

--Mark

amolaver Verified Driver Made Donation to Website
Member

Region: NASA MA
Car #: 50
Year : '96
Posts: 318
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i'm building a fresh car and ordered the rebuild kits f/r. asked around and was essentially told, 'don't bother, just buy fresh ones.'

of course, keep the source in mind - i tried to rebuild a front caliper, got the seal replaced, then the dust boot foiled every attempt and i gave up... i got a used one to tide me over, but replacing all 4 is on my winter to-do list.

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ahm - http://www.awesom-oracing.com
2009 NASA MA SM Champion

Brian Ghidinelli Verified Driver
Moonwalker

Region: SFR
Car #: 12
Year : 99
Posts: 267
Status: Offline
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How did the caliper fail?

I rebuilt my rears at the beginning of the season - it required a bit of patience but wasn't terrible. Basically you have to disassemble them from the outside in... start by popping the piston and IIRC unscrew the adjuster all the way, then you can slide out the worm gear and then remove the snap ring that holds the adjuster rod in place. At that point it should be fully disassembled save for o-rings/etc.

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MotorsportReg.com / Haag Performance / Team SafeRacer
2010 San Francisco Region SMT Champion

Gatoratty Verified Driver Made Donation to Website
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Region: Central Florida
Car #: 3
Year : 1992
Posts: 1304
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Just replaced all four. Autozone had the cheapest prices. When you add up the time it takes to rebuild them...buying new ones made sense for me.

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Paul McLester

Muda Verified Driver Made Donation to Website
ComingToAMirrorNearYou

Region: WDC
Car #: #23
Year : 1991
Posts: 642
Status: Offline
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Putting two on tonight. $68 per + a $10 core at the Rock. Autozone, $80 + $62 core.

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Muda Motorsports
"We're all here 'cause we're not all there."

Mark de Regt Verified Driver Made Donation to Website
Veteran Member

Region: NWR/Oregon; ICSCC
Car #: 70
Year : 1991
Posts: 1111
Status: Offline
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I have no idea why the caliper failed. It was an almost new (three race weekends) rebuild from MazdaComp.

I'm annoyed; I narrowly avoided smacking a wall, and (obviously) had to drop out of the race (which had been great fun up to that point).

It's clear that the one that went bad was poorly rebuilt; the dust boot was all mangled, apparently having been partially eaten by the piston; full of holes, possibly having also rubbed against the O-ring, which is mangled also.

I have given up trying to rebuild it, since apparently some special tool is needed to get the snap ring off, since it has resisted all my attempts with tools at hand. I'll get a rebuilt one from Autozone or wherever....

Brian Ghidinelli Verified Driver
Moonwalker

Region: SFR
Car #: 12
Year : 99
Posts: 267
Status: Offline
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Mark - a pair of small but long needle nose will work, perhaps in combo with a small pick. What I used was a pair of snap ring pliers with interchangeable ends from HF. I put one of the three ends on the pliers, then put THAT end into the attachment points of another interchangeable end at a right angle which made them work in the opposite direction (e.g., squeezing made them go in rather than out). It wound up looking like an L that did its job. Took a bit of goofing around to figure it out.

However, what I like about rebuilding them is aside from the labor that I know they were done right. I shouldn't have to worry about them again and I don't think the rears need to be done that often.

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MotorsportReg.com / Haag Performance / Team SafeRacer
2010 San Francisco Region SMT Champion

   

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