Brake Rebuild - Paint, Powder Coat, or Zinc Plate

[bdmiko]

As part of my rebuild I am overhauling the brake calipers. I've been following the excellent how-to guide by DeCobra and so far things are going well. Calipers are apart and ready to clean. But now here is where I have a couple of questions.

First, is it safe to just bead blast the entire caliper? Can the bore be bead blasted or do I need to protect it. Also what about the threaded holes where the brake lines screw into the caliper? Do these need to be protected too? If so, any recommendations on how to do this? I don't have the equipment to bead blast so I am planning on having a local company do this for me.

The second question is what is the best finish to give the calipers after cleaning them? The how-to guide recommends paint. I can get everything powder coated for about $150. Or should I get them zinc plated again? I found a local company that could do this as well.

Thanks
David

[kings1527]

I'm interested in this topic, too. That's going to be my next project in the near future. I had a company in town re-plate a bunch of things just recently such as my crankshaft pulley and other miscellaneous brackets and they did a good job but I'm open to powder coating, too.

[Josh]

I blasted my calipers with a garnet shot, so I cannot comment on bead blasting. You do not want to blast the bore. You can protect the bore prior to blasting with some duct tape.

I wanted to get my calipers zinc plated but the plating place did not have the capacity to do castings. So I got them powdercoated and glad I did. The quote you have for powdercoating is very cheap. Make sure they are properly taping and masking critical areas on the calipers (bore, threads, mating surfaces). I have seen lazy powdercoaters just powdercoat the whole part. Powdercoat is not fun to remove.

[bdmiko]

Actually I got 2 quotes for powder coating. One for $150 if already clean and one for $125 and they clean the calipers.

Out of curiosity, what color did you make the calipers?

[Mark D]

I sand blasted my calipers and had them yellow zinc plated... I sent them off to DMCMW who outsources the plating to a local place nearby. I thought they turned out great and should add some good corrosion protection to the internal cylinder bore.

Before sand blasting I masked off the cylinder bores....it's debatable if you really need to though. The rubber seal is the only part of the caliper cylinder that really matters. To clean up the bores I just used a red scotch brite pad, but I don't see any reason why you couldn't sand blast.

The piston walls are critical though and you don't want to sand blast on the sealing surface. If you've got pitting from rust then you'll most likely have to replace the pistons.

To protect the threaded openings for the bleed screw and hard lines I found some small rubber plugs to insert while I was blasting the parts. Check around your local hardware store and they should have some that fit. I replaced all the bleed screws so I just left them in place while blasting.

Here are a few pics
http://dmctalk.org/attachment.php?attachmentid=21837&d=1378704013
http://dmctalk.org/attachment.php?attachmentid=21841&d=1378704094
http://dmctalk.org/attachment.php?attachmentid=21852&d=1378704155

More pics here:
http://dmctalk.org/album.php?albumid=97

[Josh]

Actually I got 2 quotes for powder coating. One for $150 if already clean and one for $125 and they clean the calipers.

Out of curiosity, what color did you make the calipers?

Well I would just triple check they will do a proper job with the calipers. Powder coating must be inflated where I live compared to you then.

I painted mine red, or as I call it "Racing Red" haha. You could just as easily select grey or gold if you want a more subtle look.

I would definately go with powdercoating as it is much more of a durable finish. The calipers were zinc coated from factory, and look at them now...

2185321854

[David T]

Powder coating is not the best way to go. When it gets hot it will soften and the brake dust will melt into the paint. Plating or painting is better. The interior cylinder bore is not critical but the groove that the sealing ring goes into is as are all of the threaded holes. Check out Eastwood.com for supplies to paint them yourself.
David Teitelbaum

[sdg3205]

I used glass bead to blast mine. Then I just clear coated them. They look snazzy. Photos are available in the 2510 resto thread.

I think the zinc looks fantastic. great work.

[Josh]

Powder coating is not the best way to go. When it gets hot it will soften and the brake dust will melt into the paint. Plating or painting is better. The interior cylinder bore is not critical but the groove that the sealing ring goes into is as are all of the threaded holes. Check out Eastwood.com for supplies to paint them yourself.
David Teitelbaum

I am not understanding how painting would be better. It would soften much sooner than powdercoat and is comprimised by most any chemical (solvent based). Also it takes a lot of heat to soften the powdercoat. For how most deloreans are driven this would be a non issue as far as I'm concerned

[bdmiko]

I used glass bead to blast mine. Then I just clear coated them. They look snazzy. Photos are available in the 2510 resto thread.

I think the zinc looks fantastic. great work.

The clear coat looks nice, almost like zinc-nickel plating.

I like the idea of the inside of the bores being coated with zinc plating. The calipers have held up well for the past 30 years with a zinc coat so if they hold up another 30 years I'll be happy.

Is there any downside to zinc plating?

[Elvis]

I'd like to see powder coated calipers after some years of use.

[Timeless]

I'd like to see powder coated calipers after some years of use.
~7 years.
72260