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Author Topic: Four piston caliper re-building, stripping and painting  (Read 1248 times)
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« on: December 06, 2012, 05:40:24 PM »

I have a '68 with the original four piston disc brake calipers which I want to bead blast, paint, and rebuild. I have the following questions:

I had them stainless steel sleeved many years ago. What would be the the proper way to prep the the cylinder bores? I don't have them apart yet so I don't know what they look like inside. Being stainless, should they be OK as is?.....Would you hone or polish them in some way?

How do you clean the internal passage ways to make sure you have all old brake fluid and contaminants out and be ready for new fluid?

Would it be better to try to bead blast them and paint them before taking the two halves apart and taking the old pistons out so that you don't get any media in the bores or internal passages? Might be hard to get good access to the inside surfaces.......Or is better to completely disassemble and just protect the bores and fluid openings? I am not dead set on bead blasting. I just need to get them clean and ready for paint.

If you rebuild them and then they sit for a long period of time before being installed an actually put into use, is that OK or would the seals start to dry out?

Any opinions would be appreciated.................Dave
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« Reply #1 on: December 07, 2012, 06:41:39 PM »

Dave, not sure what might have happened from sitting but my gut feels not much. Being stainless they would not be rusting and would not think there would be a seal issue but as you stated it for sure should be checked. If I remember correctly those halfs are torqued at 90 ft lbs. When I did out 68 4 piston I painted the halfs, then cleaned up the machined surfaces since they were machined after paint, and of course nice phosphated bolts (with no paint). I think you would be better off to glass bead the assy. first and then do you inspections, etc. vs. after due to making sure no debris containimated the internals. But again, no experience in that regard.

68 Z/28 NOR 01B Orig motor/trans/rear
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69 L34 Rest. Nova Father/Son Car
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« Reply #2 on: December 07, 2012, 11:20:32 PM »

I have 'half' of an NOS caliper for a '68...  in the box..   Had it for many years (35?)..  Is there any value to just the one half?

Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
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« Reply #3 on: December 07, 2012, 11:47:39 PM »

Stainless steel sleeves also can rust and corrode after sitting for many years. The old fluids did not help the problem at all.

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« Reply #4 on: December 12, 2012, 03:37:21 PM »

Hey Guys.....thanks for all the info.

I am still unsure as how to rid the internal passage ways of old brake fluid, rust (if any), and any contaminants. And how to keep any rust from forming in there if they sit fro a long time prior to assembly.

Any thoughts on that would be appreciated......................Dave
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« Reply #5 on: December 13, 2012, 11:17:06 AM »

We recently picked up a 66 Vette Roadster that had been sitting for 30+ years, there was a sticker on the master cover that said stainless brakes, DOT 5 silicone. After going through receipts it had stainless calipers and silicone fluid put it in when they were rebuilt in the mid 70's.
We checked the fluid and bled the brakes (to ensure it was clean), changed the oil, trans and rear gear lube, then took it out for a ride, no problems, the same dot 5 silicone has been in my father's Woodie Wagon for 20+ years.
If silicone fluid is used to assemble the parts you will have no problems, BUT paint the calipers first as silicone makes it difficult to get paint to stick. 

The original paint was used more or less as a preservative between casting and machining.

Here is how they should look.


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