So I tackled this today for my front calipers, first time doing this kind of thing. Not terrible, but a couple PITA parts. I gotta say, took longer than I expected. Just me doing it. This was nearly an 8h job (including some breaks), taking my time, ensuring things were cleaned well, and the bleeding (jesus, the bleeding...)
I used the DIY I linked above, as well as following RB's rebuild instructions to the letter for the hi-temp boots. Though my calipers aren't yet trackaddict-brown, the OEM dustboots were definitely toast.
Additional tips:
-An old cookie sheet makes for a good caliper workspace to keep the brake fluid from getting everywhere
-A cut-off finger from a latex/nitrile glove with a rubber band is a great way to seal off your SS brake lines while you're doing the job
- OEM PISTON REMOVAL: for those who've never done a rebuild, using the air compressor is a nifty way to get the pistons out. The trick though is to use enough blocking material in between the 2 sides to get ALL the pistons at least part of the way out before any one of them comes out completely (since otherwise you can no longer maintain a pressure seal to act on the remaining pistons). Wood works well in between, but if using cardboard, be sure to have enough of it in between. Use more material than you think you need to prevent excessive movement by a rogue piston, you can always remove to allow more travel. Particularly if boots are toast, there will likely be at least one piston that is kind of stuck, whereas others shoot out immediately. This gave me a problem for a while.
Also, be sure to have a large channellock handy, best way to grab the last 1-2 pistons that are stuck (had to run and buy one). Since you're replacing them it doesn't matter if you mar it up. The DIY mentions prying with a screwdriver but that didn't work for me and I was afraid I was going to get it jammed in there worse
- OEM BOOT REMOVAL: this part also sucked up a lot of time. Mine were already torn at least partially when the pistons were seated, then when the pistons came out they completely separated (ripped away) from the boot's outer anchoring ring that sits -- very stubbornly -- inside the circumferential groove exterior to the piston bore. Not sure if the heat fused that ring to the caliper or what, but they were a bitch to get out. It just took a lot of patience with pick tools. Eventually you'll find a motion/angle where you see like half of the boot ring start to tilt up, then go with that and you should be able to pry it out.
- CLEANING: Generally followed what the DIY said, sprayed brake cleaner, used IronX on everything, then big flood of water through all the orifices. I did remove the 2 bleed nipple screws on each caliper. Then ran compressed air through everything thoroughly, followed by baking in a 275deg oven for ~10 minutes, followed by more compressed air. Seemed perfectly dry at that point.
- NEW PISTON/SEAL/BOOT INSTALLATION: Followed the RB instructions, everything went smoothly. Once everything was in, I covered all the pistons with gaffer tape (masking would work too I assume). I did this because I was paranoid that I would get brake fluid on the high-temp boots during the re-attachment of the caliper to the brake line, which is a bit awkward and will involve some spillage of brake fluid. I'm glad I did, I think I would have had a little contamination on one side had I not done so.
- BLEEDING: Jesus, F***ing, Christ. One thing that I did not see mentioned in researching this was how much fluid it takes to get all the air out of those front calipers. It takes
~3L PER SIDE of total volume to get the bubbles completely gone. This was with relatively frequent tapping of the calipers with a mallet and occasional pedal pushing. And no, I didn't have the bleed nipples opened too far (and sucked air in). It really takes that much fluid. Luckily ahead of time I got 3 L of cheap Motul 5.1 and used that. I put 2 L in the pressure bleeder (love the Schwaben unit), then recycled the fluid each time the drain bottle filled, back into the bleeder. I then did a DSC bleed for shits and giggles as I had a messy bleed happen last year related to a crappy Motive bleeder cap (and did get a little extra air out of the lines), then did a final bleed with the remaining 1 L of fresh fluid. The bleeding alone was ~2 hours I think. As first track day approaches I'll do a 2L SRF bleed.
That's pretty much all I can think of to add. Glad I did it myself, definitely saved some $$$. Obviously a shop would have been somewhat quicker, but with everything including the bleeding it's got to be 4h of labor for them MINIMUM (and not sure a shop would clean as well).
