My caliper adventured continue

[D60]

Don't phenolics also have the potential to "mushroom" at the pad backer? Then you force it back but the OD is larger.....?

Or is this not true of phenolics?

 

[Strumpan_]

most OE new calipers from the dealer are about that expensive




That $295 actually seems cheap for an OE new caliper for such a big truck!

I've seen higher prices for OE calipers for a Camry or Forester, and often you can't even get OE new calipers

Rock Auto has aftermarket all-new calipers for $100 for your truck. I'd trust them over lazy "rebuilds" from cores that should've been scrapped.

I never buy anything from a dealer, always 2x the price for the same part online. if i can make a brake job easier i will. i'd almost pay someone to bleed them for me if i could. i hate doing brakes more than anything but rust repair. If a car needs rust repairs i drive that car to the scrapyard.

 

[lbhsbz]

Don't phenolics also have the potential to "mushroom" at the pad backer? Then you force it back but the OD is larger.....?

Or is this not true of phenolics?

They sort of go barrel shaped and start to crush. The face of them also starts to crack / crumble, but that's pretty easily visable.

Centric used to have a bulletin, showing a cutaway with dye highlighting a bunch of small cracks/fractures in the material, but they've since taken it down since they started re-using phenolics in their reman calipers lol.

 

[D60]

Centric used to have a bulletin, showing a cutaway with dye highlighting a bunch of small cracks/fractures in the material, but they've since taken it down since they started re-using phenolics in their reman calipers lol.

This is comforting indeed!

 

[lbhsbz]

Here's the old dead link if any of you guys are good at finding cached/archived pages...

https://www.apcautotech.com/getmedi...actured_brake_calipers_-_phenolic_pistons.pdf

 

[Donald]

Calipers don't need to be honed, and there is nothing to gain by doing so....the bore is not the sealing surface, as it would be in an engine....the piston is the sealing surface.

Calipers get torn down, washed, then the castings go through a big automatic tumble shot blaster, then they're reassembled....usually with new rubber (but Cardone used to re-use boots and seals that were still "good") and either cleaned up good used pistons, or new pistons when they run out of good used ones. Phenolics should always be replaced because they fatigue and begin to fail structurally, but most now are just running them through a centerless grinder to clean 'em up and re-using them...which is crap, but it passes the 90psi pressure test so the idiots running the plants think they're good.

Here's 5 examples of "good used" pistons I pulled out of fresh reman calipers from the Cardone/Centric/Raybestos factory....




View attachment 244948View attachment 244949View attachment 244950View attachment 244951View attachment 244952

...and this is what a "good used" piston looks like that comes out of my shop.

View attachment 244954

So won't pistons with a large scratch have the plating gone in that area? Likely to rust. The manufacturer decided to plate the piston for a reason. Scratching some of it off would not be good.

 

[Rust_Belt_Pete]

So won't pistons with a large scratch have the plating gone in that area? Likely to rust. The manufacturer decided to plate the piston for a reason. Scratching some of it off would not be good.

I think we are mixing up caliper bore and piston?

 

[Donald]

I think we are mixing up caliper bore and piston?

The pistons in your pictures for the thread. Aren't they plated?

 

[Rust_Belt_Pete]

I belive so.

 

[lbhsbz]

So won't pistons with a large scratch have the plating gone in that area? Likely to rust. The manufacturer decided to plate the piston for a reason. Scratching some of it off would not be good.

Maybe not gone, but certainly compromised...and those scratches won't do anything nice to the seal.

Some pistons have the chrome laid on pretty thick. I just spent the weekend polishing a bunch down with emery tape because they showed up .002" oversized....I did the overnight rust test and I didn't polish through the plating, so there was a lot of it on there.

Minor (lathe) tool marks on the piston are OK, but anything running in the direction of the scratches in my pictures are not. Those pistons all went in the trash when I found them....but that's what seems to be normal condition pistons for commercially rebuilt calipers these days.

 

[lbhsbz]

Maybe not gone, but certainly compromised...and those scratches won't do anything nice to the seal.

Some pistons have the chrome laid on pretty thick. I just spent the weekend polishing a bunch down with emery tape because they showed up .002" oversized....I did the overnight rust test and I didn't polish through the plating, so there was a lot of it on there.

Minor (lathe) tool marks on the piston are OK, but anything running in the direction of the scratches in my pictures are not. Those pistons all went in the trash when I found them....but that's what seems to be normal condition pistons for commercially rebuilt calipers these days.

Won't let me edit, so I'll quote..lol

Years ago we had some repetitive injury issues with the caliper builders...squeezing piston in by hand all day takes it's toll on the body, but it's really the right way, unless we have dedicated fixures for everything...which is possible in new caliper production when they're doing hundreds of thousands of one part number at time...but not for the rebuild industry. The idea was to work the pistons through the seal by hand, then hit it with a pneumatic ram to drive it home. When you leave a bunch of underpaid factory workers to their own free will with limited training and poorly trained supervision...like we have at a US owned plant in Mexico....that translates into "turn the air up and drive that ****er home"....which is why it goes in all cockwards and strips the plating off the side. I can't really *****....this is the reason I'm in business selling caliper parts so people can rebuild things themselves properly, but it's still amusing and I'll still talk ****.

 

[Rust_Belt_Pete]

Rust ate through the metal reinforcing ring of the caliper piston dust boot.

 

[Rust_Belt_Pete]

3rd day of my overnight rock auto order...
Pay obscene amount of money for caliper rebuild kit and it is just sitting in the warehouse for 3 days now.
Hit the calipers with rust converter because I had free time.

 

[Rust_Belt_Pete]

Cancelled my rock auto order. Looks like the warehouse is in NC and I am not getting that any time soon.
Ordered from parts geek and it was a different brand too. Lets see if THRID time is the charm.