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Rebuild or replace brake calipers?

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#1
Sphinx

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NAPA sells new pistons and boots.  Am I better off rebuilding them or looking for quality rebuilds (or buying from one of our esteemed vendors)?  I saw all the old posts about crap rebuilds both from parts stores and Mazda.

 

Even SM rebuilders (like Drago) don't include the bracket - is replacing the bracket advisable, critical, a waste?



#2
Jim Drago

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Even SM rebuilders (like Drago) don't include the bracket - is replacing the bracket advisable, critical, a waste?

Our calipers come complete with brackets.  But if your bracket and pin are good, it does not need to be replaced


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#3
davew

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The issues with brackets are several;

 

The slots wear, at the ear of the brake pad

 

The hardware is worn, bent, rusty or missing

 

The threads are buggered up from sand blasting

 

The bolt mounting surface is covered with paint and or powder coating

 

They are bent from contact


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#4
Sphinx

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Thank you both.

 

In the interest of science, I'm going to order the parts from NAPA and lets see how they look (new pistons and boots).  I have a spare set of calipers I can mess with.  I'll report back.



#5
Sphinx

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An update - so, I went and picked up the pistons, all new rubber bushings (including the "tube" that houses the lower slider bolt) and the dust boot and seal.  The dust boots were marked as made in USA, but the package showed them to be Made in China.

 

The pistons were more interesting.  Both came in Made in Canada boxes.  They looked slightly different (looks like either two different castings or suppliers, not sure).  One weighs 13oz, one 11oz.  The OEM one was 11.25 oz.  I spoke with a chassis engineer for one of the major OEM's (has extensive racing experience too) and he said that that the weight of the pistons will not make any difference on the braking forces on the pads.  So, no reason to freak out and and swap them out with the vendor - But of course, it adds 2 oz in unsprung weight to that corner.

 

The metal on both is polished, nice.  If you close your eyes, you might feel a couple of tiny metal "burrs".  So, I'll polish them just a hair before they go on to make sure they are super smooth.

 

The calipers themselves were OEM Mazda replacements from a few years ago - so they look fine.  Will disassemble, clean, reassemble and report back.



#6
Rick Worth

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Caliper seal kits from Rock Auto (Centric) are about $10.60 for all 4 calipers. My calipers and pistons are all in good shape so once a year I clean them and install new seals with no problems. 



#7
luvin_the_rings

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my farts weigh 2oz



#8
Sphinx

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As promised, a few learnings from this project:

 

1) I went back and swapped out the "heavy" piston.  Got another with another inconsistent weight, but this time much closer, within .5 oz of the other (11 and 11.5oz).  Finish was the same, but it was obvious that they were made through different batches.  (Keeping my old pistons as they still look pretty good overall).

 

2) the piston seals bought from NAPA don't fit - they are too big; Autozone had ones that fit but with strange labels (both Bendix, I think) but one was Made in the US and the other Made in China - looked identical.

 

3) replaced the lower rubber slider tube thingie - This may have been the source of my problem where my caliper was hanging.  So, caliper replacement probably wouldn't have fixed it.

 

Of course, it wasn't worth my time to find out all of this, but it was fun.  The better solution is to replace all of the rubber bits on a regular basis rather than wait till you have an issue.  :)



#9
SaulSpeedwell

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I stopped rebuilding calipers long ago, but my primary safety/reliability concern was the quality of the piston seals.  I spent a lot of time and money trying to trace the supply base of the various aftermarket piston seal kits (Dorman, Raybestos, etc.) as well as what was being sourced in the "reman" calipers from Mazda and Autozone, Cardone, etc.  It was like a part-time job that paid negative minimum wage.

The Mazda seal kits are PRICEY, but that is what I would run in my own car, especially for situations like Canada Corner.  Although I pressure tested all the piston seals I could get my hands on, at least one supplier of piston seals was not up to snuff on being able to handle pressure AND heat.  The problem was, I couldn't be sure which kits or calipers those seals might end up in as months and years rolled by.  



 

 

 

 


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