I wrote some things lately somewhere on this site, not this forum.

It's the '05+ TRW calipers that have the real serious issues. I am really glad I don't have those, and I left the industry before the warranty really hit so have no clue what the real issue is, pistons, groove design, whatever.

'99-04 Akebono calipers is the subject. Probably the biggest issue you are going to have is having to use rebuilt calipers. This is a subject I talked about a decade ago on TDS and other forums. You can have good rubber part and well made pistons, but no matter how well the cleaning of the calipers is performed, rust pitting in the boot and pressure o-ring grooves does not establish as tight a seal as brand new calipers. So without as good a seal, rust develops sooner at those sealing points, and as the oxide expands in volume, the seal is compromised more. My solution back in the 2002 time frame was to stock up on new, not rebuilt calipers from the dealer. None of us can do that anymore.

Historically Ford's contract with the caliper supplier, Akebono in this case limits the sale of calipers to Ford only. Somehow lately Raybestos has gotten around that. Not sure if they are buying from Akebono, bought the tooling from Akebono, or just copying after the patent ran out. But they are selling new rear calipers for now. How good the castings are, how well they are machined, and how good the pistons and seal are, I have no clue.

Since I've used up all my "new" calipers, my next situation will be rebuilding my own, unless the pitting is too severe. I could try sealing the dust boots as I have done with the 4 pot Kelsey-Hayes calipers that are on the front of '65-66 Shelbys which has worked well, but those vehicles don't see the environmental conditions our trucks do. I've used high temp RTV on those.

 

 

 

 

The only way I get calipers to last is blow them apart and cover everything inside the boots with a caliper silicone ceramic grease. I rebuilt my own more than 2 years ago and have done multiple trucks and an Excursion with no issues.
The problem I find is moisture rusts the cast retaining lip for the seal. That rust grows around the piston and ends up jamming in up. You can see here the rusted lip. I get rebuild kits and clean that rust off with a round wire wheel from Harbor Freight that I put in a drill. Comes out clean then I coat everything in the grease and assemble.

 

 

The reason the industry moved away from steel pistons is braking heat transfer through the pistons to the brake fluid. The P131 brake design was all about keeping the brake fluid as cool as possible. Look at the cooling fins on the back of the rear calipers.

A properly cured phenolic piston does not suffer from swell and growth, two separate issues. What no one can tell you is if any of the aftermarket pistons have the same standards for the resin used along with the heat and pressure cycle of the OE part. I have absolutely no desire to go back to steel pistons and certainly would not recommend doing so with a caliper that was not designed for it.

Pete's silicone grease solution is probably as good as my RTV. If you look at his first image the bottom caliper bore has the rust propagating past the dust boot groove. The top caliper bore has the rust propagating down farther, into the o-ring seal. Wire brushing is effective, removing the oxides without abrading more metal away. Most of the rebuilding houses use some type of media blast to clean the bores and the exterior. That opens the bore slightly compared to factory. When I do mine I'm going to try to use Evapo-rust, but the ideal method would be electrolysis. That's way too expensive for a rebuilder. Using an acid (Vinegar, Citrus, Phosphoric, etc) I would be too worried about hydrogen embrittlement of the casting, but those might be fine. I just don't want to play lab rat and slit a caliper across it's bridge.

Until Cooper merged Wagner Brake into us I never saw rebuilt caliper returns, we never sold calipers, just friction. Looking at the returns was when the issue of pitting became apparent. The thing is you may get a decent caliper in the rebuilders box, or it may look like it was raised from the Titanic. It greatly depends on the rebuilders inspection standards and you'll have to pardon me, those are not high in my view today.

 

The goofy thing is, part of that is due to the design concern of reducing brake fluid boil. If you are not running these trucks in a commercial capacity, they run cool compared to other vehicles. So the brake parts are exposed to more dampness or wetness than other vehicles no matter the size.

Oh, there are other vehicles .......

 

I now have 2 superdutys, my 250 has been a plow truck it's whole life, now has 160,000 on it. I haven't had pistons stick on any of them yet, it's always the slide pins for me. I take them apart twice a year and clean and relube them. We use permatex purple ceramic brake grease, I apply on the Pistons and the inside of caliper where the outer pad touches. Also lube under the hardware and on top of the hardware, and clean and liberally lube the slide pins. Only way I have been able to keep them working.

 

 

Excellent guidance on this thread...

I'm going to be rebuilding my 2 front calipers -- 1999 E250 2 wh abs

Online and the local aps --- Phenolic pistons $7 - $11 each they say ?

Question -- Is that for 1 or two ? The pics are misleading and it doesn't specify. Need 2 for each caliper.

 

50k on my 2001 F-250 and 205k on my 2003 F-350, never had a slide pin frozen. I check them every oil change, and had one with resistance due to the stupid rubber bushing on the front lower pin, but never had frozen slide pins.

There were a number of us that thought the change from the Generation 1 front slide design to the Gen 2 was a bad mistake, and even worse with the Gen 3 added rubber bushing. Gen 1 was as the rear pins are, an internal boot fitting groove which tightened with any rusting, while the Gen 2 boot seal was exterior. The 2003 still has a Gen 2 with the removal of the bushing, but I have a set of the brackets from the Gen 1 series as someday backups.

Picture 2 also shows the original olive colored anti-oxidation coating extended into the bores of the brackets. Aftermarket replacements or rebuilds I don't believe do.

I just never had the problems many of you have had, but I detail out the rebuilding, mostly the way mastersativa laid out. Again, I talked about this 15-16 years ago on TDS. The caliper design is not bad, it suffers from some of the aftermarket mistakes in pads, pins and boots. And the lack of understanding that once the bracket bore rusts, cleaning it, wire brushing it, and abrading it does not stop the oxidation progression, it just removes the crust on top of the pits. You either need new virgin brackets or chemically treat the bore to etch out the process.

If one of my slide boots get damaged, it get replaced with an Akebono boot which hopefully is what ford provides in the service kits.










While the P131 Superduty was the first entry into the USA market by Akebono, if you look at the Honda Accord Akebono front caliper you see it's the same deign team, just a little brother.








Added pic, 2001? Olive colored anti-corrosion caliper vs 2003 Yellow anti-corrosion coating, pin design change Gen 2 in both.

 

As said earlier, good phenolics don't swell, but the cheap ones in rebuilt calipers do very quickly, ask me how I know.
When replaced with Wagner pistons together with the proper brake paste all has been good.

 

Just did a full round of brakes yesterday, same issues here... frozen pins. I take them completely apart once a year and clean/lube and haven't had a stuck caliper yet, but the pins seem to kill me. Doesn't matter what I do, one is either stuck or very near that point. Maybe the tire rotations at 3000 with the oil change needs to be a caliper check as well.

noticed the backing plate on the left rear is ready to replace as well.