C2 Another DOT 5 question

[Richard E.]

[Patrick B.]

[Joe L.]

Re: C2 Another DOT 5 question

Richard—- 1965 and maybe some 66 Corvettes came with caliper castings that had a provision for pistons with a guide pin made in them. I doubt if your car has them because the extra material had to be removed for sleeving, and I think all those old calipers have been replaced because of the universal corrosion issue with DOT 3 fluid. I would say it is an overwhelming certainty that the calipers on your car have been replaced at least once, and none of the replacement calipers use the unique 1965 style pistons with guide pins

Patrick-------


It is not absolutely necessary that the piston guides be removed from the 1st design calipers in order to stainless steel sleeve them. In fact, I have a such a set with NOS 1st design pistons [not for sale]. However, most rebuilders do remove the guides when they encounter these caliper cores and convert them to 2nd design

[Gary B.]

[Joe L.]

Re: C2 Another DOT 5 question

Joe,

If the piston guides are not machined away in the 1st design calipers when adding the stainless steel sleeve, doesn’t that mean that different pistons must be used which have the bottom post that slides into the bottom guide? Do any of the stainless steel resleeving companies have such pistons?

Gary

Gary------


Yes, 1st design pistons must be used with 1st design calipers (even sleeved 1st design calipers with guides). I think that caliper rebuilders used to have new 1st design pistons but I don't know if they still do. As I mentioned, 1st design calipers were usually converted to 2nd design so I don't know if there are enough unconverted 1st design calipers left to justify the manufacture of 1st design pistons. Also, keep in mind that all 1st design pistons included an attached pyroceram insulator. 2nd design pistons have no pyroceram insulator (except 2nd design with J-56 which used a different design insulator.

addendum----

I have found that CSSB offers USED 1st design pistons. I presume that if new 1st design pistons were available, they would not be offering used pistons for sale. I would not even consider using used pistons. If I recall correctly, there were once available in reproduction 1st design pistons but not including 1st design insulators. So, in that case, one would have to transfer the insulators from original pistons to the new pistons. That would be fine, in my opinion.

[John D.]

Re: C2 Another DOT 5 question

When this topic comes back up I dust off this very relevant 1981 SAE paper from the archives. It goes on to say Silicon based fluid works very well with most brake components found in our old cars and performs well when mixed with DOT 3 even at very high mix concentrations.

[Richard E.]

[John D.]

Re: C2 Another DOT 5 question

It appears that some of the current silicon fluids (purple ?) meet the newer version of that same MIL spec that now requires it be functional to -55C.


MIL-PRF-46176B, PERFORMANCE SPECIFICATION: BRAKE FLUID, SILICONE, AUTOMOTIVE, ALL-WEATHER, OPERATIONAL AND PRESERVATIVE (10-JAN-2001) [SUPERSEDING MIL-B-46176A]., This specification covers silicone-based hydraulic brake fluid for use in hydraulic brake systems at ambient temperatures ranging from +55 DEG C to -55 DEG C. The fluid is identified by military symbol BFS and NATO code No. H-547 (see 6.1). The brake fluid covered by this specification is military unique due to the requirement that it perform at a minimum ambient temperature of -55 DEG C, whereas commercial silicone-based brake fluids are rated at a minimum ambient temperature of -40 DEG C. It is intended for use as an operational fluid and preservative fluid in automotive hydraulic brake systems at ambient temperatures ranging from 55 DEG C to -55 DEG C and fluid temperatures ranging from 205 DEG C to -55 DEG C.

[Patrick B.]

Re: C2 Another DOT 5 question

Richard, I think you missed an important point of the lengthy discussions on this forum about silicone brake fluid. There was NO change in the chemical makeup of DOT 5 fluid. It is disinformation from the Corvette brake suppliers, and the EPA rule they cite has absolutely nothing to do with silicone brake fluid.

[Ed D.]

Re: C2 Another DOT 5 question

I becomes frustrating, with each question about DOT 5 on this Discussion Board, how it starts with miss information and predetermined results. It seems we need build the scientific case for DOT 5 over and over again.
Ed

[Ronald L.]

Re: C2 Another DOT 5 question

I kept mine and there were two, Lonestar being one, that would could keep those guides during the sleeping process

they were put there for a reason

[Larry M.]

Re: C2 Another DOT 5 question

Richard, I think you missed an important point of the lengthy discussions on this forum about silicone brake fluid. There was NO change in the chemical makeup of DOT 5 fluid. It is disinformation from the Corvette brake suppliers, and the EPA rule they cite has absolutely nothing to do with silicone brake fluid.

Pat:

Did you or Leif ever get a response back from Ken at Lone Star, or CSSB regarding your tests and findings?? If I recall. they were going to evaluate and investigate. They should be ready to reply back to you guys before now.

Their lawyers may have recommended no reply or no action as the best response.

Larry

[Owen L.]

Re: C2 Another DOT 5 question

It appears that some of the current silicon fluids (purple ?) meet the newer version of that same MIL spec that now requires it be functional to -55C.


MIL-PRF-46176B, PERFORMANCE SPECIFICATION: BRAKE FLUID, SILICONE, AUTOMOTIVE, ALL-WEATHER, OPERATIONAL AND PRESERVATIVE (10-JAN-2001) [SUPERSEDING MIL-B-46176A]., This specification covers silicone-based hydraulic brake fluid for use in hydraulic brake systems at ambient temperatures ranging from +55 DEG C to -55 DEG C. The fluid is identified by military symbol BFS and NATO code No. H-547 (see 6.1). The brake fluid covered by this specification is military unique due to the requirement that it perform at a minimum ambient temperature of -55 DEG C, whereas commercial silicone-based brake fluids are rated at a minimum ambient temperature of -40 DEG C. It is intended for use as an operational fluid and preservative fluid in automotive hydraulic brake systems at ambient temperatures ranging from 55 DEG C to -55 DEG C and fluid temperatures ranging from 205 DEG C to -55 DEG C.

I was going to post the MIL spec of my last order from CTL but you beat me to it. This was a new company to me as I had previously purchased through Summit and before that I don't remember. Decent price and no quibbles with ordering to delivery. (I'm sure they, like other sources, are merely repackaging/rebranding bulk drums of the fluid from an industrial maker.)

[Larry M.]

Re: C2 Another DOT 5 question

Pat:

Did you or Leif ever get a response back from Ken at Lone Star, or CSSB regarding your tests and findings?? If I recall. they were going to evaluate and investigate. They should be ready to reply back to you guys before now.

Their lawyers may have recommended no reply or no action as the best response.

Larry

Pat.......Leif:

Any comments??

Larry

[Gary B.]

Re: C2 Another DOT 5 question

Pat:

Did you or Leif ever get a response back from Ken at Lone Star, or CSSB regarding your tests and findings?? If I recall. they were going to evaluate and investigate. They should be ready to reply back to you guys before now.

Their lawyers may have recommended no reply or no action as the best response.

Larry