SharkSkin

I would think that grey spots would show up more on the black. Anyway, no concours for me either, not by a long shot. The car is a daily driver so it has to put up with the elements. The rotors will be on there for years, and while simply painting the hat would get me 99% of the way there cosmetically, preventing rust in the air passages and holes is a good thing, for lots of good reasons.

BTW are you going to SFest?

SharkSkin

Here are pics of the rotors, and a pic of the trial fit of the front caliper/rotor. More pics on the disc that is still in the camera. I'm off to the garage again, I have everything mounted up, now to go after the hydraulic & electrical part of the job.

SharkSkin

Here are some pics of the finished install after some driving. Note that, if you are a very aggressive driver, it is possible to generate enough heat to cause the cad plating to flow on the outer edge of the rotor. It's interesting that the outer face of the rotor heats up more; I'm guessing it gets less airflow than the back side. After seeing this I removed the caliper and gently pressed on the brake pedal; all 4 pistons moved more or less equally, and when I applied a spreader to move them to their original position they all moved back into the bores equally, so my first concern about sticking pistons seems unfounded. The apparent discoloration of the hat is not visible to the eye; I think it has more to do with the fluorescent lighting; the other shots above were taken with a lot of daylight in the scene. I will research this for the next set of rotors to see if there is a more heat-tolerant option available, or perhaps a thinner plating would be preferable.

Rob Edwards

Dave-

Question- what sort of prep did you do pre-PC on the calipers? I pulled mine off the car today. I know you pulled the crossover pipes and had them plated, and the guide plates and pad retainer springs too (also plated?). Did you chemically strip the calipers before handing them off, or did they media blast them, or ????? I have a bunch of 10 mm grease fittings that will screw into the brake hose, crossover pipe and bleeder holes that worked well when I stripped my last set.

Details, man, we need details!

SharkSkin

Rob, the only prep that I did was to completely strip and disassemble everything(didn't split the calipers though). They were bead blasted by the PC'er. Most PC'ers have silicone plugs that they use to fill the holes for blasting and coating but putting threaded hardware in the holes for blasting would seem to provide an extra bit of insurance.

Yes, crossover tubes, end plates, and springs were all nickel plated. Toss the screws and replace with new. They are 6x1.0x14. You may use stainless but since I had some difficulty removing one screw due to the head stripping out I replaced them with the strongest hard steel alloy screws available then took additional measures to prevent them from corroding. Stainless has the advantage of not corroding but is not as strong as the hard alloy. Also, when you get them back be sure to chase all of the threads using the proper tool(not a tap).

There are eight surfaces inside and two outside the calipers that should not be blasted or PCed:

• The innermost flat surface adjacent to the dust seals
• The flat surfaces where the end plates sit
• The flat surfaces where the screws hold the end plates in
• The two flat mounting surfaces where the caliper contacts the spindle

If they blast these surfaces but do not PC the surfaces may corrode. If they PC the surfaces, the PC will present a raised surface at the edges preventing the end plates from seating properly, and in the case of the mount points it may compromise the strength of the assembly(or at least you may have to torque it repeatedly, in theory). The guys I used goofed this up and PC'ed the areas under the end plates and I had to painstakingly level them out with a very fine, flat file. I managed to do it without breaking through the PC and the end result left plenty of clearance for the pads to move in operation but it was a real PITA that you want to avoid.

Additionally, the flat surface where the crush washer banjo bolt seals may be blasted but must not be PC'ed. If they can mask exactly on-center to the hole a 5/8" dia. mask will work, but it might be wise to mask a somewhat wider area.

So that's 11 surfaces on each front and 10 surfaces on each rear caliper that need special attention.

The most challenging part was masking the bores, since an industrial-strength bead blaster will lift the masking material that they use. They had to cut some pieces of aluminum that were clamped over the masking material to avoid this. There were some minor issues with the way this turned out but they managed to not screw up the bores.

Some recommendations for anyone looking to do this:

Place masking tape on every surface that you do not want blasted or PC'ed. Don't bother trying to get it perfect since they will remove that and use their own masking film, you just want to communicate unambiguously what surfaces should not be touched. Handing it to the guy and pointing and talking proved to be an imperfect way of getting the guy who actually did the work to do the right thing.

Provide a set of worn brake pads that they can clamp in place over the masking film to protect the bores. This will save the trouble and time/materials expense to have them fabricate plates for this operation.

When you get them back, they will have cleaned them but you will want clean the bores with a clean toothbrush, run a tiny bottle brush through all of the passages, cleaning with mineral spirits, soap and water, then alcohol and lots of compressed air to make sure there is no blasting media or other debris in there before assembly.

You may want to have them PC some pieces of scrap material that you can use to test with various cleaning agents. They may tell you it's a non-issue, but do it anyway. I used a super-aggressive brake cleaning spray that softened the PC enough that I left a fingerprint in the PC -- fortunately in a spot that is essentially invisible, between the two mounting holes.

Hopefully that will get you started; I will put the above info and details on assembly in my writeup, hopefully no more than a couple of weeks from now. I plan to be on the east coast next week so I'm not sure when it will be done.

Rob Edwards

Dave-

Fantastic information, thanks!!! - You'd alluded that getting them PC'ed was an adventure, I can see where there was some hard-won experience here....

SharkSkin

Yes, an adventure is a nice way of putting it. I should have started the process long ago, but I just kind of ignored it until the last minute, and the pressure of getting it done before SFest led to some extra hair-tearing.

BTW, I wanted to clarify that at the top of my previous post what I meant by "stripping" is nothing more than stripping hardware off. It probably wouldn't hurt to go over them with a quick simple green scrub to make sure the masking tape sticks and they can be transported/handled without making a mess but that's entirely optional IMHO.