Coated Brake Pistons

[Inv4drZm]

Since basically everybody has issues with seizing brake calipers, the engineer in me came up with an interesting idea. Why not coat the caliper pistons, which are just polished steel, with something a little more durable such as TiN (Titanium Nitride/Gold) or DLC (Diamond Like Coating/Black).

The OEM pistons themselves are $15 each, so the front is $120, plus the seal rebuild kit $20

Total of ~$150 plus the coating cost

I have no idea what the coatings will cost but if its reasonable I think it would be worth giving it a shot for a group buy. I am trying to get quotes for TiN and DLC. If its reasonable we might be starting a list boys!!!

It's either that or try and get some machined from stainless steel.

Any other ideas? Who's interested?

 

[08TxRunner]

1 - will the coating survive brake fluid?

2 - how will you account for the change in piston to caliper clearance with a coating?

 

[doofenshmirtz]

I've got a guy I do some work for that has a CNC shop that mills maintenance/replacement parts for manufacturing equipment. Their tolerances are +/-.003" against whatever specs are provided. They mill stainless and tooling steel regularly, so this would be well within their capabilities.

Shops like this aren't particularly uncommon across the US, but if I can be of help, just tag me. I could theoretically buy a piston and model it in Solidworks to get a quote. If the coatings were to add an appreciable thickness, you could custom mill pistons to account for that.

As it stands, I don't yet have any skin in the game, because I've got lifetime warranty on my calipers, but it's fun to help out when I can.

 

[Inv4drZm]

1 - will the coating survive brake fluid?

2 - how will you account for the change in piston to caliper clearance with a coating?

As long as the orings aren't leaking you shouldn't need to worry about brake fluid compatibility.

DLC coating is .00025 inches thick. Even if the metal surfaces were used to seal instead of the oring the coating wouldn't interfere with anything.

I've got a guy I do some work for that has a CNC shop that mills maintenance/replacement parts for manufacturing equipment. Their tolerances are +/-.003" against whatever specs are provided. They mill stainless and tooling steel regularly, so this would be well within their capabilities.

Shops like this aren't particularly uncommon across the US, but if I can be of help, just tag me. I could theoretically buy a piston and model it in Solidworks to get a quote. If the coatings were to add an appreciable thickness, you could custom mill pistons to account for that.

As it stands, I don't yet have any skin in the game, because I've got lifetime warranty on my calipers, but it's fun to help out when I can.

I've got a couple shops here I'm more or less friends with, and have calipers and modeling software as well but thanks for the offer.

Some more notes:
4th gen calipers us 45.5mm pistons, which have no aftermarket support that I could find.

5th gen calipers use 48mm pistons which apparently are used by Porsche 911 calipers and come in anodized stainless versions.

 

[SeanWN86]

I feel the problem is half the piston, and half the bore. So they both need coated.

I've just replaced mine. Again. And have been thinking along this same idea for when I need to replace again.

Sub'd.

Since basically everybody has issues with seizing brake calipers, the engineer in me came up with an interesting idea. Why not coat the caliper pistons, which are just polished steel, with something a little more durable such as TiN (Titanium Nitride/Gold) or DLC (Diamond Like Coating/Black).

The OEM pistons themselves are $15 each, so the front is $120, plus the seal rebuild kit $20

Total of ~$150 plus the coating cost

I have no idea what the coatings will cost but if its reasonable I think it would be worth giving it a shot for a group buy. I am trying to get quotes for TiN and DLC. If its reasonable we might be starting a list boys!!!

It's either that or try and get some machined from stainless steel.

Any other ideas? Who's interested?

 

[81runner]

Haven't needed to replace a caliper yet, but I'm all for bullet proofing everything I can. Count me in. I have several machine shops and coating and plating shops that I do regular service for. I could likely get this done in exchange for services and keep the price low, especially if there is a decent volume on it, depending on the approach used. What about cerakote? Not sure final thickness, but if it's only a couple of thousandths, it wouldn't be a problem to get pistons either machined from scratch or turned down to allow for tolerance.

 

[Ed_C]

Truly Fixing Seized Calipers

 

[SeanWN86]

Truly Fixing Seized Calipers

+1 what I plan to do if I ever need to replace mine again.

 

[nevada]

Since basically everybody has issues with seizing brake calipers, the engineer in me came up with an interesting idea. Why not coat the caliper pistons, which are just polished steel, with something a little more durable such as TiN (Titanium Nitride/Gold) or DLC (Diamond Like Coating/Black).

The OEM pistons themselves are $15 each, so the front is $120, plus the seal rebuild kit $20

Total of ~$150 plus the coating cost

I have no idea what the coatings will cost but if its reasonable I think it would be worth giving it a shot for a group buy. I am trying to get quotes for TiN and DLC. If its reasonable we might be starting a list boys!!!

It's either that or try and get some machined from stainless steel.

Any other ideas? Who's interested?

are the pistons polished, or chromed?


years ago I had a customer with a 79 corvette. those cars have terrible issue with the pistons seizing up, due to lack of use. the cars typically get parked much more than they get driven.


anyway, he was doing a full restore on it, and knew it would be sitting for a long time. so he sent the calipers off, and had stainless sleeves pressed into the bores. apparently it was at a company knowing for dealing with that issue. it cost him a lot, well over $1k for this work.


when it came time to get the car out on the road again... he had the same old problems. some pistons were seized and others were leaking. the extra prep work on calipers made zero difference..

 

[Inv4drZm]

are the pistons polished, or chromed?


years ago I had a customer with a 79 corvette. those cars have terrible issue with the pistons seizing up, due to lack of use. the cars typically get parked much more than they get driven.


anyway, he was doing a full restore on it, and knew it would be sitting for a long time. so he sent the calipers off, and had stainless sleeves pressed into the bores. apparently it was at a company knowing for dealing with that issue. it cost him a lot, well over $1k for this work.


when it came time to get the car out on the road again... he had the same old problems. some pistons were seized and others were leaking. the extra prep work on calipers made zero difference..

Not sure on that one, some have said they are chrome plated, and that seems the norm elsewhere the more I do research so they probably are.

But assuming the pistons are already chrome plated, I would only really need to coat the calipers.

Cerakoting is very popular and some websites offer caliper coating services pretty cheaply, and it's thin enough it can be applied everywhere and comes in any color.

DLC is stronger though if I can find a place that will do calipers for the right price.

 

[Inv4drZm]

Couldn't get a quote from anyone for DLC coating, but got one for Cerakoting.

I asked if they could do the piston bores and potentially the pistons since they are prone to seizing. This is what he had to say:
"I would advise to not do the pistons and the bores if there is a known problem."

I'm still not sure why not, the coating is only 1 thousandth thick? It should only help right?
For 4 calipers it will be $60 each.

 

[Inv4drZm]

Does anyone know if the remanufactured semi-loaded caliper options out there have as good of pistons as OEM? I believe OEMs are chrome plated. Has anyone seen aftermarket last as long as OEM? I might just swap out the pistons for OEM if they are better, I can buy an OEM piston to compare with.

 

[Piggity]

I'd look into a different caliper altogether since the 4th and 5th gen calipers are steel aren't they? Take a look at Lexus IS350 calipers.

I know on the 1st gen Lexus IS300 forum I'm on they have a guy selling 2nd gen Lexus IS350 caliper adapters (look up 350phi on IG) that bolt onto the IS300. The rotor width and diameter is similar to the 4runner so I'm sure it could physically fit, plus the caliper is aluminum. Obviously it would require someone creating an adapter.

 

[SeanWN86]

Does anyone know if the remanufactured semi-loaded caliper options out there have as good of pistons as OEM? I believe OEMs are chrome plated. Has anyone seen aftermarket last as long as OEM? I might just swap out the pistons for OEM if they are better, I can buy an OEM piston to compare with.

Found out if oem is chrome plated?

 

[Inv4drZm]

Found out if oem is chrome plated?

Not sure.

 

[randy88fj62]

The pistons are not chrome plated. That would be prohibitively expensive. Those talking about cerakote, that would not add any corrosion or abrasion resistance.

The titanium nitride (or copper nitride for that matter) usually needs to be plated on a material that will accept it such at nitralloy 135 (that material is used on fighter jets). You cannot machine nitralloy or nitride coatings easily so you would have to pay a grinding shop to hit the final OD of the piston ($$$).

So at the end of the day you're better off buying a new set of OEM calipers and change your brake fluid every year if you're worried about corrosion,

You can also pull off the dust boots on each piston and regrease them periodically. You're trying to reinvent the wheel where it's not necessarily warranted.

-aerospace engineer

 

[JuniorPigeon]

Has anyone noticed a lesser amount of seizing based on which fluid they use?

I'm about to change my rotors and pads out and I'm going to full fluid flush as well. I used to use ATE Super Blue back in my racing days which now seems to be the ATE Type 200 Amber fluid now, thinking about that as it has good water binding properties.

Anyone use the stuff in our 4th gens?

 

[lbhsbz]

The OE pistons are not just polished steel, they are chrome plated. They have excellent corrosion resistance. The issue is that moisture collects around where the boot fits to the casting...then slowly creeps under the boot and around into the bore where as the paint or zinc plating degrades, pinching the piston...as seen in your picture.

The problem becomes worse in rebuilt caliper because the surface where the boot fits is no longer a clean machined surface, but a blasted more porous surface...so the boot doesn't seal as well as it once did.

Once the caliper is all cleaned up and re-assembled, pull the boot back and squirt it full of silicone dielectric grease...then burp the air out until grease oozes out of it. Once it's full of grease, it won't get able to get full of anything else and it will live considerably longer.

This is not a toyota specific problem.