Mike J

As part of my annual maintenance cycle this year I want to powder coat my calipers "Big Red Red" but have a few concerns about the process. While several people on the list appear to have done with without removing the seals and pucks, the powdercoating people I have talked to here in Vancouver would prefer the caliper be stripped down with no rubber seals etc. They are concerned with the temperatures involved.

So I guess the question is : What is the maximum temperature these brakes get to under track conditions (i.e. the design limits)?

I run ATE® Super Blue (DOT 4) which has a dry boiling point of 536F and a wet boiling point of 396F. Have not boiled the brakes yet but I am sure its possible. The interesting thing is the powdercoating is appied at 400-425F, so in theory on the track if you run hot enough to boil your brake fluid you could be above the melting point of the powdercoating!

Anyone know the maxium temperature that the rubber seals are designed for?

If I was going to do it right I would strip down the brakes but they are currently in fine shape and I don't want to pay for new seals if I don't need them. Definitely masking them off and going that route is the easiest way.

Any ideas?

Thanks!

Mike

GrantG

The rotors on my 944 Turbo S (similar power, weight and brakes to 993) would get bright orange at the track. The temps are considerable and I would concur with the shop that to do it right, you should dissassemble the equipment. Otherwise, you may be looking to re-do it soon...

Mike J

Thanks Grant,

They must have some pretty special rubber in those seals to take that kind of heat. Do you boil your brake fluid when running that hot?

Oh, I am thinking the opposite of you. If the rubber and brakes can take that kind of heat where the disks start to glow, then a little powdercoating at 400F should be not problem. Assuming some masking, does that make sense?

Cheers,

Mike

Bill Verburg

The Brembo spec on the inner pressure seals is 360F max

I believe that the Powder coat ovens are ~400F

You do the math

Mike J

Thanks Bill,

Hmmm, that means that the seals will fail before the brake fluid boils...that's kindof weird isn't it?

It points that all the seals should be removed before they calipers are powder coated....I guess I need to look up that DYI!

Cheers,

Mike

Greg Fishman

Don't know the temps but my Big Reds are more of a Big Maroon color now.
Might not be a bad idea to rebuild the calipers anyway. The parts aren't expensive.

JC in NY

That's so funny you mentioned that Greg. This past summer a guy brought his mint 3.6 turbo to the track and his pristine, bright red calipers turned maroon. He looked at them and with a disappointing tone said "Well, I guess I need to buy new calipers now".

Bill Verburg

It just means that they need to be rebuilt regularly if they get that hot. As Greg/JC mentioned they can get hot enough to singe the paint.

Steve Weiner-Rennsport Systems

LOL,..Now you know why all racing calipers from Brembo, Alcon and AP are anodized, never painted.

Ragin' Bajan

Yes, they would, but remember you're quoting the boiling temperature of the brake fluid, which doesn't really have anything to do with the temperature limits of the caliper seals.

Good luck w/ your project!.

Bill Verburg

The issue is time /temperature related the higher the temp the lower the useful life. The seals get hard and inelastic when overheated, of course at some point their life expec5tancy goes to zero

AP says max caliper seal temp ~240C, 200C for 1 hr etc. It is obviosly non linear.

L23FPorsche

I would like to continue this discussion as I will be powder-coating calipers in the near future. Many have done this w/o removing the seals or dissassembling the calipers. Robin Sun for one. I would rebuild but the kits are NOT cheap ($185/pair). Has anyone had problems after PCing their calipers? Also where or who is doing the best job?

Tom

Matt Romanowski

If you notice, usually the first thing to go is the dust seals. Overheated brakes can kill them very quick. On our formula car, we leave the dust seals out.

Matt

Mike J

I have never taken apart one of these calipers so I am unaware of the seal structure. There must be external dust seals (as mentioned by Matt) and then the internal ones. Maybe we can just take the dust seals off and mask the rest?

I am still unsure on what approach is the best if money is an issue (and it is!).

Cheers,

Mike