Rebuilding and painting my calipers

[FireFox31]

I received my two remanufactured calipers from FCP today. Looks like the one on the left came from Sveedy in Arizona and the right came from abscate in NY. The right one already has rust on it and its clear coat is cracking. This is why I hate rebuilt calipers and did everything I could to save mine.

I'll disassemble them tonight and inspect their pistons. I'll be furious if their insides look worse than my old ones.

My plan is to send these two new calipers and my 2 and 5 year old front calipers away for powder coating next week. I am hoping that will protect them from rust much better than the garbage coating used by the remanufacturers.

[FireFox31]

I removed and inspected my front calipers. The left one is five years old and the right is two years old. Shortly after buying them, they became rusted beneath their thick clear coat. Not long after, the coat started flaking off. I really think this is a fault of rebuilding, not just because I live in New England.

The two year old piston already has a blob of rust just above its boot. The piston still easily retracts fully into the caliper body. The five year old piston is fully rusted around its boot to the point I couldn't easily pull back the boot. That piston wouldn't easily press fully into the caliper by hand, thus wouldn't mount back on the car until I used pad spreaders. With some more rust, it might get stuck inside the caliper body.

Do I consider either of these calipers failed due to the piston rust? Do people outside of New England experience this kind of rust on rebuilt calipers in such a short time?

[ZionXIX]

Being from Texas I've never experienced that level of rust. Not even junk yard calipers come close to that monstrosity. I've often thought about trying my own powder coating with a harbor freight kit and toaster oven.

[GlennG2759]

If your going to paint your calipers. POR-15 makes a complete kit for this available on Amazon. I have the kit but haven’t used it yet (saving for a winter project). It has some very good reviews and supposed can be used over rust.

[FireFox31]

I've decided to replace all four calipers, giving me the best possible base for powder coating and all new pistons. This is costing me $550 for the calipers (would be $750 but one is replaced by FCP) and maybe $300 for powder coating. The only remaining challenge is monitoring the coating and the pistons for rust. I'm working to find a source for replacement pistons since they rust out in 3-4 years.

[scot850]

We have the same issue here. Problem we have is if you paint or coat the remanufactured part within the warranty period you invalidate the warranty. Many only have a 1 year warranty, so I have to wait a year and then paint them.

I have used the duplicolor caliper paint but it does not seem to last as well as it used to. I don't think the product is the issue put the de-icing agent (liquid death) they have been using for the last 6 years or so which is highly corrosive. Por-15 does not even last up here. I have cleaned to bare metal, treated with rustbuster metal treatment and then painted with Por-15. Less than 2 years and rust came through again.

Neil.

[volvolugnut]

When I worked for equipment manufacturers that sent things to coastal and off shore areas, they had paint systems for extreme service. Initial prep was a near white metal sandblast. These were three coat systems starting with a Zinc rich first primer to anchor the paint. Second coat was intermediate primer and then an epoxy top coat. A clear coat may be added for appearance only. These coating were thick - up to 15 mils total.
This system is expensive and time consuming, but worked well for several years. But it would not last forever.

volvolugnut

[FireFox31]

Maybe the real solution is rust management, cleaning the caliper and repainting it every year. Is there a recommended cleaning interval and procedure for calipers? When I'm at the car wash, I avoid spraying my brakes since they're hot from driving there.

Still, the piston heads rust. abscate and I are working to find replacement pistons. How could we remove the rust, create a perfect surface, and add chrome like the rebuilders?

Problem we have is if you paint or coat the remanufactured part within the warranty period you invalidate the warranty. Many only have a 1 year warranty, so I have to wait a year and then paint them.

I asked FCP about this. They said powder coating calipers bought from them would not affect the warranty. "People do it all the time," they said.

[volvolugnut]

Power coat is good, but not great for corrosion protection in severe service. What ever the coating, start with bare metal as clean as you can get.
volvolugnut

[FireFox31]

Since one of the rear calipers I bought was already rusting in the box, I ordered a replacement using the FCP warranty. It arrived and, sure enough, it was also rusting inside its sealed bag from the remanufacturer. So, I ordered a third one because I insist on using the best material possible before paying for powder coating.

Aside from a large rust spot, there's a thin layer of rust spots all over the caliper underneath the clear coat. I think the rust remains in the pits when not sandblasted carefully enough, blooming out and ruining the caliper. I will ask the powder coating shop to sandblast it deeply and apply rust converter before priming, powder coating, and clear coating.

When I worked for equipment manufacturers that sent things to coastal and off shore areas, they had paint systems for extreme service. Initial prep was a near white metal sandblast. These were three coat systems starting with a Zinc rich first primer to anchor the paint. Second coat was intermediate primer and then an epoxy top coat. A clear coat may be added for appearance only. These coating were thick - up to 15 mils total.
This system is expensive and time consuming, but worked well for several years. But it would not last forever.

I intend to do this to my rusty spare set of calipers. abscate gave me some nasty calipers to send back as cores, letting me keep my rusty but functional rears for this test. My plan is to remove the flaking metal with a lightweight needlegun scaler, sandblast them as deeply as possible, apply rust converter, then use the process described above with high zinc primer, intermediate primer, than top coat. The hardest part is maintaining the correct sizes for the bore opening, piston boot holder, and pad holding slots (on the rears).

Maybe I can apply POR-15 or the marine paint to the piston heads since they're the weakest part of the system. Until I can find a cheap source for these disposable pistons, I have to protect what I've got.

I'm also considering this marine paint for other metal parts under the car. I just changed my fuel filter and bought a new bracket since I knew mine was rusty. That rusty bracket will be the very first thing I test all of this rust rehab on.