C3 Brakes - Reseal or replace calipers

[Terry Baumsten]

My 80 has been in storage for many years and the calipers were leaking. Upon removal of the pistons there was a lot of sludge inside and the pistons showed some oxidation. The bores are SS sleeved and cleaned up pretty well. Should the calipers be replaced or just cleaned up and resealed?

[Jeffrey S.]

Re: C3 Brakes - Reseal or replace calipers

Terry:
If you are sure that the calipers are stainless sleeved, then there is no reason to replace them- just re-seal them. If they were mine I would probably convert them to o-rings while I have them apart, especially in the rear. I did mine several years ago after air pumping caused the rear brakes to become non-functional and I had to bleed the brakes much too often. I haven't had a bit of trouble since.
Hope this helps.
Jeff

[Joe L.]

Re: C3 Brakes - Reseal or replace calipers

Terry-----

If the calipers have been previously stainless steel sleeved, you don't need to replace them. Simply clean up the caliper bores, IF NECESSARY, with a very light polishing with crocus cloth.

In most cases, to rebuild the calipers you will need to replace the pistons and in ALL cases you will need to replace the piston seals and dust boots. To determine if you need to replace the pistons, carefully and closely examine the sealing ridge of the piston which is that part of the piston immediately forward of the seal groove and which contacts the caliper bore. If any of the gold anodize is worn off the piston at any point on the circumference of this ridge, then the piston needs to be replaced. I think that you will find that all of your pistons will suffer from this.

I used to be a fan of the stock-type pistons and seals. However, I've been "won over" with respect to the newer o-ring type pistons and seals. They've now stood the "test of time". Everything that I've heard about them has been great and I've never talked to anyone that had any problems, at all, with them. My next caliper rebuild on my 69 will involve the use of these.

[Steve L.]

Re: C3 Brakes - Reseal or replace calipers

What is crocus cloth?? I've seen this mentioned for years particularily when talking about caliper cylinders, but I've never seen this stuff unless it is another name for emery cloth??

Steve L
73 coupe since new

[Terry Baumsten]

Re: C3 Brakes - Reseal or replace calipers

Crocus cloth is similar to emery cloth but very very fine grit. I think used a lot in the jewelry biz for removing scratches. I think you can it find at a good auto parts store.

[Terry Baumsten]

Re: C3 Brakes - Reseal or replace calipers

Thanks Joel. I think I knew that, but needed to get some stopping ability as the car is going in for engine R&R this week and so I just cleaned, resealed and bled the system. I think when I get it back, I'll need to address the calipers again with the o ring approach in mind.