C2 brake caliper advice request

[Eugene B.]

Members,
While attempting to bleed the brake calipers on my '65, I experienced multiple piston/seal leaks on multiple calipers. The original 1st series calipers were remanufactured a couple of years ago by one of the major rebuilders. The rebuilder says that he will repair them under warranty.

I am questioning whether this is the best solution to the problem. Am I only chasing a future recurring problem by trying to keep the original calipers on the car?

Would I be better off to have the original calipers rebuilt again with all new pistons or should I archive them and install new o-ring calipers and save a future headache?

If buying new calipers is the smartest way to go, who supplies the best?

Thanks in advance to all who reply.

Regards,
Gene

[Joe C.]

Re: C2 brake caliper advice request

Gene,

Your original calipers can be rebuilt and upgraded by eliminating the phenolic "hockey puck". This modification cannot be detected without removing the pads. If you consider this sacrilege, then remove them and install a reconned set from a later model. Your call!

The calipers on my '65 are from a '70. I rebuilt them 5 years ago, and they have been dry ever since. You MUST replace all pistons, even if they look AOK, because if even the slightest bit of anodizing is missing, especially in the seal groove, you are looking for trouble.

Joe

[Joe L.]

Re: C2 brake caliper advice request

Joe-----

In 65-E67 "1st design" calipers, the Pyroceram-insulated pistons cannot be eliminated without also eliminating the piston guides cast into the caliper bores. Another way of stating it is that the insulated pistons with rear guide pins are the only pistons that can be used in these calipers UNLESS the caliper guides are machined out. Once this is done, the calipers can never be returned to "1st design" configuration.

The piston guides in the bores can be readily machined out, though, and this is done almost routinely by caliper rebuilders when they encounter "1st design" castings. After the piston guides are machined out, then the "2nd design" non-guided and non-insulated pistons (or, aftermarket o-ring type pistons) installed.

[Joe C.]

Sanitized

Joe,

That's right. Once upgraded, they cannot be returned to original config. That's why I mentioned that Gene might consider it a sacrelige to modify them.

I have a full set of unmolested '65 calipers stored in my attic, but I keep the '70 units installed on my '65 because I can't bring myself to machine and update the first designed castings.

Joe

[Eugene B.]

Re: C2 brake caliper advice request

Joe & Joe,
Thank you both for your replies. I think my problem stems from the rebuilder reusing my original pistons. Do either of you know where I can purchase NEW "1st design" pistons?

Best regards,
Gene

[Joe L.]

Re: C2 brake caliper advice request

Gene------

I think you can obtain them from Lonestar Caliper or Vette Brakes and Products.

[Eugene B.]

Re: C2 brake caliper advice request

Joe,
Thank you for your reply. I talked to Ken at Lonestar yesterday and obtained the following information about new "1st design" pistons. Not good news from my perspective.

The new pistons are kind of a hybrid between 1st design and later design pistons. That is to say that they have provisions for attaching the heat insulators to the piston, but the internal features are not compatible with the guide rods in the 1st design caliper halves.

To use these new pistons, one must modify the caliper halves to remove the guide rods. Looks like the new pistons are good for applications where you have later design calipers that you want to make look like 1st design calipers. The new pistons are $30 each.

I do not intend on modifying my original calipers. Ken is convinced that he can make them leak tight again, so I'm willing to let him try. If all else fails, I'm going to archive my originals and purchase new calipers with all new pistons.

Best regards,
Gene

[Joe L.]

Re: C2 brake caliper advice request

Gene-----

The pistons that you described that you were told about are the reproductions of the 2nd design J-56 pistons. They use an insulated version of the 2nd design piston. As you described, it uses no piston guide pin (like all 2nd design pistons). It also uses a much thicker insulator and correspondingly thinner piston than the 1st design insulator and piston. I was aware that Lonestar now offers these. However, I thought that they also had available the 1st design pistons, too. Apparently not, though.

You might also try Vette Brakes and Products. They used to show the 1st design pistons in their catalog. However, I've been told that when you try to purchase them, they don't have them. It's worth a call, though.

If your pistons are in good condition, you can re-use them. However, pistons are rarely in good enough condition for reliable re-use.