Help identifying alleged S4 rear calipers
10-05-2009, 07:47 PM
#31
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Yep, same caliper(or other side). PC, also end plates, springs and crossover tubes bead blasted and nickel plated. I'm debating whether I need some kind of rubber sleeve on the crossover tube per original. I'm not even sure what purpose it's supposed to serve.
10-05-2009, 07:55 PM
#32
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Gorgeous- Did you re-do the seals and pistons post-PC? I know people seem to err towards replacing caliper pistons and seals if they're to be PC'ed because of the heat but one sees these calipers on brake dynos with red-hot rotors and I can't help but think that the piston seals would handle an hour at 350 degrees F. Or maybe I'm wrong......
10-05-2009, 08:26 PM
#33
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Yes, I did it post-PC. The PC guys insist. What I was told is that it's not so much about the seals as they want to make sure they have all oil out of the assembly. Getting them to this state has been quite the adventure... I'll tell you over a drink -- I need one if I'm going to revisit all of that! 
There have been other challenges along the way but none so humorous as getting them refinished.
There have been other challenges along the way but none so humorous as getting them refinished.
10-05-2009, 08:45 PM
#34
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10-05-2009, 09:54 PM
#36
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Wow that looks awesome! Nickel plate will hold up nicely and will make clean up easy. I had my rotors on my Mercedes nickel plated and they looked great. Made cleaning a snap and really improve the look.
10-05-2009, 10:09 PM
#38
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Steve, Ashfin, thanks. I had the rotors cad plated(bright, not yellow). The guy who's been doing plating for 40-odd years said it would hold up best at the higher temps. He could have also done yellow cad, zinc or nickel. The rotors almost look too pretty to use. 
I wish there were a black treatment that would offer the same corrosion protection, that would just be too cool -- pun intended, as it would probably radiate heat better as well. 
I wish there were a black treatment that would offer the same corrosion protection, that would just be too cool -- pun intended, as it would probably radiate heat better as well.
10-06-2009, 12:12 AM
#39
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Dave-
Got pics of the plated rotors? I didn't realize you could plate 'em. Did you have new rotors plated, or did you clean up the old ones, and if the latter, can they be media blasted? The hats of the rotors on both cars look like crap but I've never gotten around to painting them. Plating sounds like a nice option.
Got pics of the plated rotors? I didn't realize you could plate 'em. Did you have new rotors plated, or did you clean up the old ones, and if the latter, can they be media blasted? The hats of the rotors on both cars look like crap but I've never gotten around to painting them. Plating sounds like a nice option.
10-06-2009, 02:34 AM
#40
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Rob, no pics yet. I inspected them at the plater's and boxed & taped them back up. They are sitting on my rear floorboards. I have so much garage space taken up by other stuff right now I don't have anywhere else in the garage to put them without tripping over them. Friday evening I'll probably get started and I'll take some pics then.
I had new rotors plated, so it was a simple matter for them to degrease them and plate them. I'm not sure bead blasting would get deep into the vanes, and if your rotors are drilled then trying to blast those holes would also remove material around the holes -- you'd have to get them re-ground. They could be etched, but the etchant can find its way into pores or cracks in the castings and never really rinse out. That's sort of theoretical... My experience with metals, etching and plating was mostly focused on high-vac lab equipment and electronics, so these concerns may be non-issues in this application. What you need to do is find a reputable plating shop and talk to the salty old guy that's been there forever, and get an expert's advice.
You could certainly get just the hats blasted(mask the friction surface) and paint them for appearance sake. Are they fairly fresh rotors, or would it make more sense to just plate the next set?
Oh, I just remembered, you have a media blaster now. Yeah, you could fix those hats up in an hour or two, not counting the "getting them on and off" part. 
I had new rotors plated, so it was a simple matter for them to degrease them and plate them. I'm not sure bead blasting would get deep into the vanes, and if your rotors are drilled then trying to blast those holes would also remove material around the holes -- you'd have to get them re-ground. They could be etched, but the etchant can find its way into pores or cracks in the castings and never really rinse out. That's sort of theoretical... My experience with metals, etching and plating was mostly focused on high-vac lab equipment and electronics, so these concerns may be non-issues in this application.
What you need to do is find a reputable plating shop and talk to the salty old guy that's been there forever, and get an expert's advice.You could certainly get just the hats blasted(mask the friction surface) and paint them for appearance sake. Are they fairly fresh rotors, or would it make more sense to just plate the next set?
Oh, I just remembered, you have a media blaster now.
Yeah, you could fix those hats up in an hour or two, not counting the "getting them on and off" part.
10-06-2009, 03:00 AM
#41
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Dave-
The GTS has drilled rotors on it right now (well, they're lying on the floor), they're well within spec thickness wise but they're rusty and there are small cracks around the holes. Dunno if anyone would touch them on liability grounds. Likewise the rotors on the GT, they've got a decent lip on them now. I have new GTS rotors, perhaps I'll just plate those and throw those on.
The GTS has drilled rotors on it right now (well, they're lying on the floor), they're well within spec thickness wise but they're rusty and there are small cracks around the holes. Dunno if anyone would touch them on liability grounds. Likewise the rotors on the GT, they've got a decent lip on them now. I have new GTS rotors, perhaps I'll just plate those and throw those on.
10-06-2009, 03:14 AM
#42
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Yeah, I wouldn't do it if they are cracked. IMHO it's better to think of plating as preventive rather than corrective procedure. If the old ones can be ground and meet spec, you might be able to get a few bucks for them, especially if you offer to blast and prime the hats.
10-06-2009, 12:09 PM
#43
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Dave, I know its too late, but there is a black zinc plating process done by a shop up in santa clara- I don't know how if the color would survive the heat. I just sprayed mine with cold-galvanizing zinc- but I knew my car would beat up on the track, so I didn't go for much cosmetic prep. Still trying to get it on the track...lol.
10-06-2009, 03:05 PM
#44
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Dave, I know its too late, but there is a black zinc plating process done by a shop up in santa clara- I don't know how if the color would survive the heat. I just sprayed mine with cold-galvanizing zinc- but I knew my car would beat up on the track, so I didn't go for much cosmetic prep. Still trying to get it on the track...lol.
10-06-2009, 07:54 PM
#45
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Dave, yeah the stuff turning green is what I heard also...but 3 years in, my zinc spray is still grey, so it hasn't corroded much, but I can see rust around places where I missed on the rotors. Damn. No concours for me!