Truly Fixing Seized Calipers

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Ngonerogwu

Member
So, my 2003 has gone through 6 calipers at this point... it's getting old (literally LOL)

After looking at some pictures of failed calipers, I've got an idea. I picked up a set of new Raybestos calipers, and I'm going to coat the pistons and bores with a ceramic dry film lube. You spray it on with an HVLP at about a half mil thickness, 0.0005" so it wont affect fitment. The stuff prevents corrosion and isn't affected by brake fluid.

It's the same stuff I'd shoot on piston skirts.. NIC makes it, called Microslick.

V3cEs0C.jpg


Anyways, I've shot a piston so far, fits fine unsurprisingly. Next I'll see about doing the bores.


Here is one of the pistons coated.

ZugJKxu.jpg


Here is test fitting in a caliper half..

84LUO8U.jpg


Someone wanna talk me out of this before I go further? I couldn't find anyone online who's done this with any caliper.
 
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Very interesting. BTW, Your pictures aren't working.

This is something you are going to have to report back in time (I dunno, several months, maybe more). I just replaced my front calipers (after doing the legendary 5th gen brake upgrade......... which is honestly a crock) a couple of months ago, but I'm not going to hold my breath on them lasting more than a couple of years. If they do, I'll be happy (which is pathetic).

good luck!
 
CookieRoe said:
Very interesting. BTW, Your pictures aren't working.

This is something you are going to have to report back in time (I dunno, several months, maybe more). I just replaced my front calipers (after doing the legendary 5th gen brake upgrade......... which is honestly a crock) a couple of months ago, but I'm not going to hold my breath on them lasting more than a couple of years. If they do, I'll be happy (which is pathetic).

good luck!
Click to expand...

OOOKAY, hopefully they work now.
 
ZiaMan said:
I've brought this up once before here and on another forum. The two big things are:
- Will coating create issues with clearance?
- Is the coating compatible with brake fluid - being that it will be in contact 24/7 for months and years?

The other options would be some sort of titanium nitride coated brake pistons like here:
4 x Titanium caliper pistons | Vehicles & Parts | https://titanclassics.com

LOVE that you are doing this!
Click to expand...

Coating is VERY thin. Can't measure it on my calipers kind of thin. I have a coating thickness gauge and it meters out at an average of .5 mils. Which is 0.0005" thick.. its seriously thin.

S5NWSx9.jpg


I shot this test piece and sanded it down in different spots along the bottom. Part with 1000 grit, another with 1500, another with 4/0 steel wool, and then left a side alone. Soaked it in brake fluid outside for week to see what would happen. Nothing.. I mean not even a little bit, no color change on a white paper towel wipe etc. Does that change in a couple years? Maybe, but brake fluid seems to do its thing pretty quick.
 
Sub'd

Be interesting to see how the brake pistons and bores hold up long term....can only see the coating helping with the longevity.
 
[MENTION=135208]Ngonerogwu[/MENTION]
I think something like this is the only thing that will work. The 4 caliper design was used in the 60's and failed then too. They work great on race cars but not so much in the real world. A single system piston moves a greater distance and with more force at a given pressure, pounds per square inch. A four piston caliper divides the movement distance and force by 4. So in the elements they stick. I think just coating the piston will solve the problem.
 
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V8Man said:
[MENTION=135208]Ngonerogwu[/MENTION]
I think something like this is the only thing that will work. The 4 caliper design was used in the 60's and failed then too. They work great on race cars but not so much in the real world. I single system piston moves a greater distance and with more force at a given pressure, pounds per square inch. A four piston caliper divides the movement distance and force by 4. So in the elements they stick. I think just coating the piston will solve the problem.
Click to expand...

It's easier to just coat the piston for sure.

Looking at pics of failed calipers, it appears that the seals suck, and let water past, and the top part of the bore above the seal becomes a horrible mess. If I apply the ceramic to the bore, then we should be good to go.
 
CookieRoe said:
I just replaced my front calipers (after doing the legendary 5th gen brake upgrade......... which is honestly a crock) a couple of months ago, but I'm not going to hold my breath on them lasting more than a couple of years.
Click to expand...
My plan was to flush out the calipers twice a year and see if that helps. The thought process is doing so will get out any moisture that's in there causing them to freeze. Am I wasting my time?
 
Montego Murph said:
My plan was to flush out the calipers twice a year and see if that helps. The thought process is doing so will get out any moisture that's in there causing them to freeze. Am I wasting my time?
Click to expand...

No, I don’t think so, preventative maint seems great.

Look at some of the pics you can find on the forum of people who’ve managed to get the pistons out. The bore above the seal gets absolutely trashed.. feels like if I could prevent that corrosion, we’d be good to go.

I refinished a set of calipers off a Lexus LS400 recently, and noticed the pistons were coated with something, and the bores had been anodized. The calipers themselves were in awful shape, but the bores and pistons were pristine. Got me to thinking.. we can’t anodize but if we could do something to prevent that corrosion from starting.. at the very least we’d extend the life of them. There’s loads of room in the bore around the piston, as the seal is the only bit that touches.

I’d think really the ideal thing would be a stainless piston and a coated bore. I can’t afford to have pistons made so this is what I’ve come up with instead.
 
Very interesting experiment. I just wish someone like Powerstop that already sells nicely coated calipers would go the extra mile and use stainless pistons. I mean, how much would it add to the manufacturing cost? Maybe $10 per caliper at most? I’d gladly pay an up charge for that, as I’m sure most here would, just to save the worry and hassle of having to inspect, flush, clean, or replace these things as frequently as we do! When mine failed, I opted for the 5th gen “upgrade”, only to find out that the old, seized stuff had already been “upgraded” by the previous owner! I opted for Powerstop stuff mainly for aesthetics and extra corrosion resistance, but I’m sure I’ll still need to check the pistons and clean/relube them to get some longevity out of them. I will say that the parts and overall assemblies seemed to be much higher quality than any parts store rebuilt I’ve ever used, so hopefully they last.
 
Ngonerogwu said:
Coating is VERY thin. Can't measure it on my calipers kind of thin. I have a coating thickness gauge and it meters out at an average of .5 mils. Which is 0.0005" thick.. its seriously thin.

S5NWSx9.jpg


I shot this test piece and sanded it down in different spots along the bottom. Part with 1000 grit, another with 1500, another with 4/0 steel wool, and then left a side alone. Soaked it in brake fluid outside for week to see what would happen. Nothing.. I mean not even a little bit, no color change on a white paper towel wipe etc. Does that change in a couple years? Maybe, but brake fluid seems to do its thing pretty quick.
Click to expand...

Had this same thought about coating the piston (next time I do brakes). Sub'd..
 
gTpsFjP.jpg


I did some more thinking and looking at the pics of failed calipers and this is what I decided would help.

I may still do the pistons, but it looks like most of the corrosion happens above the seal inside the bore. The pistons appear to be plated (hard chrome maybe), so not sure coating those is gonna do me any good.. that's unfortunate because its easier to jusy coat the pistons for sure :-)

I didn't mask anything other than the mating surfaces, so all the ceramic that's not on a machined surface is going to be blasted off. Not like the overspray will hurt anything, but figured if I'm going to do this, I'm going to do them properly.

I tested the fitment with the coated piston and they drop right in like normal, no issues.

YmaVIPW.jpg


I am likely going to leave the coating on the machined sliding surfaces you can see.. not sure if it'll matter though. I've done calipers that have slider/shim inserts that the pads ride on.. our calipers don't have those. Pretty sure the powdered calipers you'd buy from powerstop are powdered there so it probably doesn't matter. I also decided to coat the pins in the hopes that will prevent binding.
 
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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)
 
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