Caliper Coatings

[theclaw]

Ok, I didn't listen. Over the winter when I rebuilt my brakes, I also had them bead blasted to get 23 years of gunk off them. Now they are corroded. I used some rust remover but that didn't really do the job. I don't want to put any caliper paint on top of a cruddy surface so I'm left with some options. First, I'm going to put them back on just to run them. I'm thinking when I have some time do I....

1)Re-blast them and paint with a high temp coating

2)Re-blast them and find someone to re-anodize them. If this is it, who does this?

3)Just buy some new ones and hope ebay can defray the cost

Oh, its a '84 Carrera. I don't need a "brake upgrade". I've searched the posts. The stock brakes on this car are fine. For my level of track driving I really need a "brake applicator upgrade".

[Oh Haha]

Get them clean and rust free and then spray them with Dupli-Color Wheel paint. I used the standard silver on mine 2 years ago and they look great still. They have but a few choices for colors but it seems to hold up very well, even on hot brakes.

[BertBeagle]

In my work I see this from time to time when folks want to refinish a painted caliper. I have also seen it with anodized calipers.

If you are going to refinish painted calipers (ie Brembo Porsche OEM calipers that are typically red or black) there is a set sequence that will give like new results.

You do not want to strip a caliper body of all its paint and anodize and then repaint the outside and assemble. This will leave the bores bare aluminum and this will ultimately contaminate the brake fluid turning it black, lowering the boiling point and increasing compressibility.

The Brembo calipers are anodized under the paint. Some new Brembo calipers (examples: F-40 calipers similar to Porsche and some Lotus calipers) are painted after final assembly including the bridge pipe, exposed piston ends and rubber dust boots. This is an accepted way to do it and avoids the step of masking the bores and assembly after painting.

However, this is the method we have use on the few that we have re finished:

1. Strip old paint via abrasive blasting with a fine medal that leaves little texture. Avoid blasting in the piston bores if there is no paint there. I would not have the powder paint stripped by cooking it off which is the practice most powder coaters use. The oven heat to cook off the paint is much hotter - to the point of damaging the aluminum caliper body, than the baking heat initially used to set the original powder paint finish. The heat to set the paint is typically not more than 300*F and is not damaging to the aluminum.
The paint striping process is the only time I would use abrasive blasting on a caliper body. We use soda blasting to clean them but that will not remove power painting.

1A. If the caliper has an anodized finish then send it to the anodizer for striping. This process will also leave a textured surface finish like the fine abrasive media blasting.

2. After stripping tumble the bare caliper body in a hard polishing media (not a cutting media) to remove the texture or fuzzy finish left by the media blasting. With the polishing tumble media we use this process takes about 15 / 20 minutes of tumbling. The bare caliper bodies come out of this process with a low polished finished and no trace of the textured finish that the media blast process leaves.

3. Have the bodies anodized - clear, black, red - it doesn't matter. Anodize is a perfect base finish for aluminum that is to be powder painted and it prevents aluminum oxidation from contaminating the brake fluid. This must be done by a good anodize shop that understands that you are particularly interested in the bores and fluid passages and you don't want any erosion of the seal groove, bores, or threaded ports. The whole process can go to hell in a hand basket at this stage with an accident by the anodizer.

4. Clean and assemble the caliper including bolting the caliper halves back together (new bolts), bridge pipe, bleed screws and rubber caps. Leave out the dust boots, pressure seals and the pistons.

5. Mask the piston bores including the groove where the dust boots fit or have the powder paint shop mask them before painting.

6. After the calipers come back from powder painting remove the piston bore masks. Do a final cleaning and blow out with air. Install the pressure seals and pistons using a thin film of silicone assembly lube such as Dow 111.

An alternative is to plug the bleed screw and bridge pipe ports for painting and then install the new bridge pipes and bleed screws after painting. I think this give a nicer finish but they are just brake calipers hidden in the wheels. Like I pointed out above you can simply powder paint the entire assembled caliper and the 300*F oven baking will not hurt the rubber seals.

I have done a few using the method above but due to cost it would likely be less expensive to simply find a nice used set to replace the damaged ones - installing new seals, dust boots and bleed screws. Most people would cringe at the cost to have a repaint done correctly.

[BertBeagle]

After reading the original post again it seems that the caliper in question might be iron.

If that is the case you can blast away and paint with several choices of rattle cans or powder paint.

But the best would be to first have zinc, cad or other plating applied and then paint. This will protect the bores and fluid passages.

I guess I wasted a lot of typed words on the first post but then maybe someone will make use of it for aluminum calipers they can't pull themselves to trash for new ones.

[barney911rs]

These are not aluminum calipers, so most of the concerns mentioned by Bert don't effect you. Good info for others reading this thread. If you have a local powder coater, that would be better and more durable then paint. Option 1 should be sufficient for those calipers, if you choose not to powder coat. Just make sure the pistons, bleed screws, seals, etc are all working correctly before re-installing.