REMAN CALIPERS Rear Phenolic pistons??

[V10nacuda]

REMAN CALIPERS Rear Phenolic pistons?? factory? see pic

I have been poking around for replacement calipers & noticed most have a Phenolic pistons What are they from factory??? Chrome??



What kind of service are you guys seeing with these remanufactured ones????



Are they as good as OEM replacement??



V10

 

[JR]

I have zero faith in reman calipers anymore. Rebuilding your OEM will be cheaper and will probably get you better results. They are easy to do

 

[jelag]

The problem with the phenolic pistons occurs when dirt gets past the boot and scratches the piston. . these scratches allow the piston to bind against the seal or leak. . so inspection is important... but chrome plated pistons can have damaged as well... if an excessive amount of water gets into the caliper, rust can lift the chrome... also the piston can be damaged from dirt that passes the boot...

In either case... its my personal belief that the large rebuilders do a reasonable job to control quality. . I'm guessing that some of the larger ones who are trying to uphold the quality might be using new pistons on each caliper so they know they are dealing with a known good surface... However I also agree with diesel4life... if it was my truck I'd do my own... . in fact I annually bleed/flush the system to keep good brake fluid at the caliper to prevent the moisture problem... I'd also like to share that if the boot is in good condition, and its not pulled away from the caliper or piston I'd just compress the pistons... pushing the old fluid to a container, and install new pads, cleaning and lubricating the contact surfaces and return the caliper to service... .

 

[V10nacuda]

I have been pretty good with service up until now & usually just push the cylinders back. But this time the pad was gone and was metal on rotor & got kinda hot & the rubber boot is shot!!

Do I need a brake hone to do the rears??? or will a wire wheel & scotch brite be enough??

Thanks

V10

 

[JR]

I haven't needed a honer on any of the calipers I've done. Be careful with all of the sealing surfaces, scotch brite or really fine sand paper like 600 grit should do the trick. If your pistons are in good condition you can reuse them but if they are scored or pitted they will eventually leak past the seal.
Jim brings up an important step that a lot of people skip on or don't do enough which is flushing the brake fluid. Bad fluid is a cause of a lot of caliper failures.

 

[jelag]

The seal on a caliper runs against the surface of the piston so as you inspect/change the piston your improve the surface... so honing the caliper is something that's not done... however behind the seal (square o-ring) dirt can build up and that needs to be cleaned... including the area behind the seal... also remember that the seal is moving across a surface (piston) that will not rust... Also the dust boots on a caliper is a much better seal, than the covers on a wheel cylinder... and keeping out the dust is as important as keeping clean brake fluid in the system. .

If I have a caliper that I need to work on... I pull the pistons, remove the seal (square o-ring) (actually a quad-ring) and than wash with solvent and a brass brush... than a pass through a hot water washer to remove the solvent... SOLVENT ON THE PARTS DURING ASSEMBLY WILL DAMAGE THE SEALS

In a wheel cylinder... the cups run across the bore of the wheel cylinder. . so wheel cylinders must always be honed... if you compress the cups when replacing shoes, you push the cups across all the dirt that's in the wheel cylinder and it almost always will leak... if the brake fluid in the system hasn't been kept clean. . the moisture will rust the bottom of the bore and as the cup is pushed across the rust it will damage the sealing surface on the cup. .

Thus, wheel cylinders need more service of a higher level than disc calipers...

Brake fluid is hygroscopic, which means it will absorb water... of course the system has to be vented to function so water will work its way to the system... I personally will use a vacuum pump and flush/bleed the breaks usually every year or two... I try to do that when I do my winter checks... but the process has been defined to start with the longest line... right rear, and add fluid to the master cylinder and either pump the master cylinder or apply vacuum to the bleeder and allow it to run until the fluid is clear... on my dually that means about a full quart of brake fluid to do the complete job... it comes out, dirty yellow. . and of course is clear...

I don't save brake fluid... once I open a container I use it all or throw it away... year old fluid on the shelf will be yellow. . a sign that's it has absorbed water...

Sorry for being so long winded...

 

[V10nacuda]

I pulled the right rear one apart to see if the cylinder was scored & this is what I found. I got the truck with 30k on it, I cant imagine there were replaced under warranty???

Its phenolic with a metal cap.

Is it factory???

 

[jelag]

Great photo... its scratched and would damage a new seal that would run against the piston... I can't tell if it would be something that I might try and repair... if I couldn't catch my finger nail on it... as I drug it across the scratch I might use a 600-800 grit paper and see if the scratch can be removed... or I'd go to rockauto.com and just order replacements... but the way they now are... is not acceptable... for re-use...

 

[JBallou]

Rockauto has become my favorite for getting parts. Local stores never seem to have what I need to complete the job, only some of the parts. Oh they can order it, so can I.

Here is a discount code for your using pleasure

1672869813959932 expires October 20th.

Standard disclaimers apply, I'm not affiliated etc.