Lots of masking, and some blasting... now ready for even more masking.

Novel idea, not sure how many of us would have the patience and skill to do this. I found new, not rebuilt, calipers for the front, installed those and installed my third set of rebuilts on the rear. My plan is to thoroughly bleed the brakes once a year and lubricate the slider pins as part of my regular maintenance routine. No idea if any of that will help, hopefully the new calipers will work better than OEM did and then rebuilts have a lifetime warranty from NAPA so I'll just keep exchanging them if necessary. Now that I live in the desert southwest, moisture and corrosion become less of an issue (I hope)

Beautiful work, will be watching closely!

These are done, starting on the rears after work.

Wow those are purty. Do you run a coating business?

I'm not really sure that the seals "sucking" is the main issue. After all, the square-cut seals effectively keep the high pressure brake fluid in the cylinder. If they were really letting water in at normal atmospheric pressure, then brake fluid would also be leaking out due to the increased hydraulic pressure. Obviously water is getting somewhere, otherwise we wouldn't be dealing with these issues. The natural degradation of the fluid through it's hygroscopic action introduces excess water from the inside. In my recent front caliper change, I initially intended (i.e.hoped) my pistons were in good enough condition to clean them up and install a new seal kit. I found my piston boots were toast. They just crumbled and as I tried to remove the C-clips I found several tears in the boot folds. So, water and all kinds of other grime was getting to the piston surfaces that way as well.

As annoying as it is, it seems that regular fluid flushes and regular maintenance of the rubber "dust" boots should keep them in the best condition. I can't see how the 5th gen brakes are any better... other than that they are brand new at installation. It shouldn't be any different than replacement 4th gen calipers. After market replacements probably have different metal compositions than OEM ( I guess). Maybe Toyota addressed the piston corrosion issue and made the 5th gen pistons out of a different metal/alloy/etc. I guess only time will tell if there has been that type of change. I know one of the 1st guys to do the 5th gen upgrade said the pistons were a different size. I don't suppose anybody could confirm the change in material to something less prone to corrosion... IDK, I'm just throwing out ideas. The ceramic coating seems like a good idea to my non-expert self...

Anyhoo... I now need to do a complete fluid exchange and I plan on installing a re-boot kit on my other front caliper and I think I'll look into a re-boot kit for the rears. I'm fairly sure those rubber boots are shot as well. Hopefully I can catch any potential issues before they cause problems.

Nice, keep it updated. Don't suppose they make that in an aerosol can? Picking up some Cerakote-d exhaust parts tomorrow, good stuff.

Bob, I do agree with everything you've said and making sure to not only maintain the dust boot but also I would add some brake grease inside the dust seal as a part of that maintenance... but I do think that when the OP said water is getting past the "seal" and causing the piston and bore to corrode and seize he meant the dust boot since he then stated that it was corroded above the "seal"...then he was meaning the actual brake fluid seal/oring in the bore, I also agree that water contamination in the brake fluid could also contribute to them seizing but I'm thinking that less of a problem than the dust boot allowing water, road salts, etc. in around the top of the piston, if this was a major contributing issue to them seizing then all calipers on all makes of vehicles would have just as much of an issue as we have on our T4Rs.

Fully agree... I don't believe water is getting past the square seals in the bore, so I didn't coat the bore below the seals.

The boot design is absolute crap, and its easy to see that the retaining ring can't do a good job of holding boot tight enough to prevent water from making it around. Other calipers have an insert at the top of the bore that gives a lip that prevents water making it around..

Other calipers are more like the design of our real calipers, where that seal is more inset into the body (brembo is a good example). After taking apart the rears.. i don't think I'm going to ceramic coat anything more than the pins. I don't see how water could possibly get past the outer boot.

You're right tho, fluid changes are KEY to protect the inside of the caliper. I'm just trying to control the external factor (crap boots).

Haha, no sadly they don't.

You gotta really control the thickness on this stuff, and its difficult even with a nice gun.

The hard part is really the prep and the masking honestly. If the prep is wrong, you gotta start over.

Squirt the boots full of silicone dielectric grease after you put 'em back together....it'll create a boundary seal and they'll work fine.

Rears are done now.

Ton of smoothing on both the carrier and the caliper itself.

These are the nugeon branded calipers. The seals are CRAP. Picked up some Raybestos ones just in case.. glad I did. MUCH better quality. The Nugeon ones are crazy thin, and feel really junky.

Any updates?

@Ngonerogwu Ever install? I'll offer my services to test for ya

I know its not as good of a solution as you have, but perhaps a little easier. Would using a product like this be worth while?

https://www.amazon.com/3M-08946-Clea...ct_top?ie=UTF8

I'm thinking when I get my 'new' calipers from Napa to slightly pull the pistons out and add some of this between the pistons and the seal, as well as everywhere else brake grease is supposed to go.