I purchased a 71 coupe a couple of years ago. The other day the brakes failed. I disassembled all four calipers and found out that the calipers have stainless steel inserts.

The fluid in the system was NASTY and I believe that the contamination allowed the seal in the rear caliper to fail. There was also dust and crud behind the boot seal that may have helped the seal fail. The boots and seal looked to be in good condition and still failed.

I'm going to rebuild all four calipers and already have a complete seal kit. About 10 years ago, I rebuilt the calipers in my truck. In the kit there was a special lubricant that was applied to the "INTERNAL" caliper rubber piston seals that was compatible with the brake fluid. I looked for that seal lubricant at three different parts places today and no one had any idea what I was talking about. I know it exist and I also know that I can just use the brake fluid to coat the seals when I re-assemble the calipers. Has any one seen a lube like this?

I'm not new to rebuilding calipers but, the C3 calipers are a little different than most calipers. If you have any tricks of the trade that you can pass along that helps the caliper last longer or work better, please let me know.

I purchased some Permatex brake parts grease "the green external grease" and plan on coating the external rubber boot seals with some of it to help them stay plyable and seal better.

I am also going to paint the exposed parts of the calipers RED with Duplicolor Caliper Paint kit, replace the rubber lines with braided stainless lines, flush the system with new synthetic DOT 4 fluid, and while I have the car on stands, replace all the front suspension bushings. The steel brake lines look good and I didn't have any problems getting them off.
I did however break one of the front caliper bleeders off in the caliper! That sucker just wouldnt come loose.

Ive tried all of my standard tricks to get it out but have NOT been successful as of yet. Heat, penetrating oil, easy outs and drilling have yet to get it to comply. Still trying. If i cant get the old bleader removed, what repairs are there to save that caliper???

Thanks in advance for any information or recommendations that you may pass along.

Bill C

 

HEy Bill, when I did my 71 I got the "O-Ring" seals and each one came with a little tube of white grease for the O-ring. As far as I know it was lithium grease but I am not certin. I had to remove a broken bleeder from a caliper years ago but all I ued was a tap and die set, was pretty uneventful actually.

Good luck,
Don

 

use Scotch Brite pads and some WD 40 to clean the SS sleeves.

 

I did the job a year or so ago with the 'o'ring pistons. I cleaned all surfaces with 1200 grade paper and haven't had a maor problem except with the bleeders. I used stainless bleeders and I don't think the taper on them can be the same as steel ones (or perhaps the metal being much harder damages the caliper) and one has to be tightened to the point of almost stripping and still weeps. If I was to do the job again for the cost involved I would just replace all the calipers with new units - job done - then no worries

 

I'm just happy someone else replaced the old calipers with stainless sleeved ones! I'll get that broken bleeder out one way or another.

Has anyone else painted their calipers??? How did they turn out and did it last for a decent period of time?

Thanks

Bill

 

I used 'Hammerite' satin black last year - they are still fine, no flaking.

 

Generally, just brake fluid is recommended to lubricate the caliper piston seals. You really don't need anything else.

 

Definitly use the "O"ring replacment kit as mentioned earlier,far more superior then lip seals.Whatever brake fluid you use is all you should need to lubricate your seals. Later Geno:

 

I mixed Bill Hirsch Black & Silver Miracle paint to simulate raw cast iron. Painted the calipers about 8 years ago and they look like the day I painted them. That paint is impervious to everything, including brake fluid. Wearing gloves is a must, otherwise you have to wait for the paint to wear off your skin. Even lacquer thinner won't touch it.

 

I used duplicolor caliper paint and let them sit for a week. When I bled the brakes the paint came off. I don't think their caliper paint is any different then the rest of their paint.

 

I recently did a complete brake overhaul on my '85 Corvette that I purchased new. It was the first time the brakes had ever been touched and even though the car only has 8k miles on it, I was expecting at least one caliper to begin leaking any time now. The fluid was the original fluid put in at the factory and to my surprise, not one caliper was leaking.

I stripped the calipers and bead-blasted them before painting them with some Eastwood AlumaBlast to replicate and maintain the natural look of the Girlock calipers. However before painting them, I placed them in the oven on 200 degrees for about 30 minutes to get them warm. I them shot them with a good heavy coat and returned them to the oven for another 30 minutes before doing one additional coat for complete coverage. I then "baked" them one last time for about an hour.

After they had cooled and I removed the tape from the piston bores, I reassembled them with the new seal kit using just a bit of brake fluid to lubricate everything. I would normally have used Silicone, Dot 5 fluid, but decided at the last minute to go with some ATE Blue that I recently purchased.

I flushed all of the old fluid from the system with new Dot 3 fluid and then flushed the new fluid from the lines with the ATE Blue. After reassembling everything I then completely bled the system using the ATE Blue.

Needless to say I did get some of the ATE on the newly painted calipers in the process, but the paint was not harmed. I suspect that the main reason for this was that the paint had been baked on the calipers and is much more resistant to brake fluid.

I also bead blasted the rotors and caliper brackets and used Eastwood Spray Gray on the rotors and brackets. I also used the same "baking" process as I did on the calipers. Everything looks like the day I picked it up and should last another 23 years... well maybe this time I'll get around to flushing the brake fluid a time or two.

I mentioned the Dot 5 because I've used it on a number of C3's in the past as well as numerous other vehicles with excellent success. One of the many advantages of the Dot 5 is that it will not harm the paint if you should get some on painted surfaces.

Good luck... GUSTO

 

I also would recommend the o-ring pistons. I painted my calipers with Rustoleum Industrial Red paint. Seems impervious to brake fluid. I also race the car and get very hot brake temps and the paint hasn't failed. I do get a few nicks where I knock the paint off changing wheels but all I do is clean the caliper and touch the nicks up with a brush. Has worked great for 4 years and a lot cheaper than caliper paint.

 

O Ring replacement seals? I think I missed something! PLEASE explain more about this O ring thing I have $80 worth od regular seals ready to install. If O rings are Better please explain. Where did you get the O rings and if there is a specific O ring to find, please let me know what it is.

Thanks

BC

 

I personally have never used them but I plan on it for the next rebuild.

http://www.vbandp.com/detail.aspx?ID=830

LL&P
Tom1701

 

Bill,

Because the C-3's use a fixed caliper, rotor run-out is much more critical than it is on cars with a floating caliper such as the later model Corvettes. A little too much rotor run-out can result in the calipers ingesting air as the pistons attempt to follow the rotor. This problem usually surfaces after the rotors are replaced as the factory did an excellent job of matching rotors to hubs and mounting replacement rotors can throws this out the window.

The O-ring seals do a much better job of compensating for this run-out than the normal lip-type seals do so they have become a preferred method of dealing with this problem. This solution also requires the use of a specific piston, so they are typically sold in a kit as Tom1701 indicated above.

If you get the run-out low enough, it should not be an issue, if not, you may end up frustrated from having to repeatedly bleed the air out of the calipers. There are a number of methods of working on minimizing run-out and if you do a search, you can probably find it, including the run-out specs. You can also PM Gary (aka GTR1999) as he's written a number of papers and is a real expert on the subject.

Good luck… GUSTO

 

I think you are correct about the run-out issue. The caliper that failed wasn't riveted to the rear hub. The rotor on the opposite side was fine and it still had the OEM rivets.

I will for sure check that run out and see if what it is.

Thanks for the excellent information and recommendations.

Bill

 

Bill:

I also sheared off a bleeder during a brake bleeding session. This is a pretty common problem. I had no luck with penetrating oils and easy outs. One suggestion I received was to use a left handed drill that was just a touch smaller than the minor diameter of the bleeder threads. (Left handed drills bore the hole while going counterclockwise.) I bought one of these drills, ran it down the bleeder and voila, the remains of the bleeder spun right out. Use a little bit of caution with this method, if you drill too deep you can hit the seating surface of the bleeder.

They also sell bleeder insert kits where you can drill out the bleeders completely, retap at a larger size, and then screw in the insert.

 

Cris

I going to have to try your recommended fixes. If all else fails, where do they sell those insert repair kits??

The other FRONT caliper was previously repaired with one of those kits. Look like it works well.

Thanks

Bill

 

Bill:

Since the left handed drill worked for me, I never used one of the repair kits so I can't recommend one or the other. You might start here:

http://www.toolsource.com/14in-disc-...r-p-54435.html

Cris