951 Caliper Restoration - Info Dump

[amartella]

Hello friends

I recently took a deep dive into restoring the Brembo calipers on my 951 - I'm hoping this info dump of methods and parts can help someone else who wants to give this a shot

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1. Removing the Caliper Brackets (by far the worst part):
Each caliper has two brackets that span between the caliper halves – the brackets help keep the pads in the proper position but must be removed to split the caliper halves and get full powder coat coverage. Each bracket is fastened by two 4mm button head allens that will strip 90% of the time (100% in my case).

The way you remove the allens is by using a Dremel to cut a slit in the head of each bolt, apply heat to the area with a small torch, then use a strong screwdriver to break the bolt loose. (I tried to use a Husky 3/8 socket-to-flathead adapter on a ratchet and bent the flathead on the first go. Get a real screwdriver.)

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The heads of these bolts are quite hard to access so this job gets a lot easier if you also use a Dremel to cut the brackets such that you can split the caliper and gain top-down access to the bolts. However, these brackets are expensive to replace; the cheapest I found was $51/each on Paragon Products.

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I cut the brackets on the first caliper so I could figure out how to get the bolts out. Once I landed on the Dremel method, I cut the head off a screwdriver and held it with a pair of vice grips for a makeshift 90* flathead. This allowed me to remove the other bolts without having to cut the brackets and split the calipers.

2. Removing the OEM Finish:
Fortunately, I have access to a media blaster at work - the silicon carbide dust made quick work of the faded stock paint/powdercoat.

I didn't cover any of the bleed ports because I was going to split the calipers and give them a good flush anyway

I also did not remove the pistons or the seals before blasting, just tried to push them down into the bore as far as they would go. Some might argue this is the wrong thing to do but I was more worried if i removed the pistons and taped off the openings, if the tape failed then I might damage the inner bore with the blast media - Im standing by this decision.

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3. Removing the pistons:
With the crossover pipe and bleed screws still tight, 50-60PSI of air applied to the input port on the backside of the caliper should be enough to pop the pistons out. I found that a 1-inch-thick piece of whatever you have lying around inserted between the pistons is perfect for getting them to come out evenly. If you don’t put something between the pistons, the loosest one will come out first and then you’ll lose all your pressure.

I’m not sure if this was necessary but I noted down which piston came out of which bore to make sure they went back in the same place.

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3. Powder Coating:
I wanted to do the calipers in Speed Yellow, fortunately Prismatic Colors will sell you a pound of speed yellow powder for $27!
https://www.prismaticpowders.com/shop/p ... rU6xnPUvWd

Before I did any powder coating, I inspected the piston seals and scrapers. They all looked to be in good condition, so I did not remove or replace them, just taped off each bore with Kapton tape. I figured if they can survive the heat of brake use, they can survive a few mins in an oven.
I wanted the Porsche lettering on the front and the Brembo lettering on the back to be black against the yellow caliper so this was the process I used:
1. Tape off piston bores and plug brake fluid ports with sacrificial M10x1.0 bolts from the hardware store. I also used the original caliper bolts to join the two halves (I had already ordered replacements)
2. Spray black powder locally on the front and back side of the caliper
3. Bake for full cure cycle (15min @ 350*F)
4. Let cool completely
5. Spray yellow powder on entire caliper and carefully wipe off lettering
6. Bake for full cure cycle (15 min @ 350*F)
7. Repeat steps 4-5-6 one more time.

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4. Caliper Brackets – Revisited:
I did not want to buy new caliper brackets for $50-70 each to replace the ones I had cut…. on principle. So, I took some measurements and ordered new ones to be laser cut out of 1.5mm 316 stainless steel from Send Cut Send. It was $35 for 8 brackets

I couldn't have SendCutSend bend them for me so I just did it with a bench vice and some elbow grease

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5. Replacement Hardware:
You can buy replacement hardware for cheap on McMaster.com. I opted for the blue zinc plated bolts because I thought it looked good against the yellow. Here are some links

Button head for caliper brackets: https://www.mcmaster.com/catalog/91306A671
M10 Caliper Bolt: https://www.mcmaster.com/catalog/91502A234
M12 Caliper Bolt: https://www.mcmaster.com/catalog/91502A253
M10x1.0 fluid port plug: https://www.mcmaster.com/catalog/91180A363

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6. Cost Breakdown:
Facebook marketplace Eastwood Powder Coating Kit: $50
Black Powder: $20
Yellow Powder: $27
Kapton Tape (high temp resistant): $40
Replacement Hardware: $70
Prestone DOT 4 Fluid: $12
Total: $219

[Carmagic]

They look great. As long it's not for a racecar the powder coating is fine.

I coated a set of 964 calipers which I used for my 71 911. I used used a heat dissipating ceramic coating.



Cheers
Engelbert

[ROB III]

@amartella
VERY timely post, I have been under the back of my car for several days trying to determine the source of a disturbing noise, and was looking at my calipers thinking its time to address them, and I was even considering going with yellow.
Great write-up.....THANK YOU!