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I want to bring all readers up to date on what I have accomplished and learned thus far.

I have selected 100 customers who have purchased a BTV rebuild kit and am preparing a questionnaire which will include the reaspon for rebuilding such as: in the course of restoration/ hard pedal/ no pedal upon removing car from long period of non-use/ catastrophic failure in use/ gradual failure in use etc etc.

I have had 10 used units in my stock put aside for internal analysis. So far I have removed the compensating valve/spring/nut assembly and examined them.
Findings:
All 10 leaked when I tried to blow through them by putting my lips to the threaded portion. All were then disassembled Conclusions: 1. When "dry" and not immersed in brake fluid it is not possible to determine if there would leak in service. 2. All have substantial deposits of what looked like "dirt" and are probably rust or from dirty fluid.3) These deposits, from visual examination, would likely cause the valve not to seat 4) Although all were from units out of use and therefore had spent over 10 years with the valves "tipped" only 1 showed signs of a "dented" rubber face. My GUESS is that the system had some petroleum product in it an caused the valve rubber face to soften and deform.

Further analysis to be done:

Finding the presence of "dirt/rust" which might cause abrasion of the primary rubber seal and leaking, I will remove the seals and examine under a microscope.

RESEARCH WITH INDUSTRY EXPERT

I have spoken to one of the largest power brake unit rebuikding companies which has been doing BTV's for many years. In his experience there are two reasons for BTV failures. Comp valve leaking due to incomplete sealing. This is caused by foreign material or deteriorated brake fluid in the system. Fluid loss caused by leaking of the fluid into the vacuum section and being sucked into the intake manifold. Low fluid causing loss of braking. Cause, leaking of the primary seal and the fluid getting by the secondary seal instead of back into the reservoir.

Note: This problem can be caused by the use of an incorrect reservoir cover gasket which blocks the fluid return passage. This has been oted in previous posts in other forums.

OTHER MEASURES IN PROGRESS:

Wear and age are inevitable ( I recently noticed that I'm 65 despite my best efforts not to age) and the eventual wear of components will happen. I will design a simple retrofit BTV cap with a low-fluid sensor and a light to put below the dash. This will give an adequate early warning just like modern systems, similarly can be used manual brakes 35-up.

RESPONSES FROM MY PREVIOUS POSTS:

I requested to hear from members about their catastrophic failures. Heard from one who posted in the forum

Offered a free compensator valve from anyone who felt theirs was defective. NO responses.

Helpful and constructive comments/criticisms welcome. All others can air their differences at your next meeting of the Flat Earth Society

Fred Kanter
Kanter Auto Products
Boonton NJ

Having a 56 Clipper equipped with a BTV, I say thank you.

Tom

Might be considered as not constructive criticism, go to the next UFO's Anonymous meeting!!!

You're welcome, nontheless.

Thanks Fred for a rational look at a very serious problem. I'm one of the group that would just as soon keep my BTV.
Been driving Packards since 1953, when I learned how to hotwire our Mayfair.

Fred

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My remark was ment as a sincere thank for the effort made by you to look into the BTV problem, making it safer, as I want to continue using my BTV.

I hope I can avoid going to the next UFO`s Anonymous meeting.

Tom

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Now THAT is a capital idea! Simple, effective and combined with the knowledge of using the right parts should prevent most btv issues before they come "crashing" down.

Rocky:

See you tonight at the 12 step "I just saw Elvis" Anonymous meeting.

Fred

Fred,
While it will be a while before I get to the BTV on my '55, I am grateful for your research into this issue. I too want to keep the original system in my Patrician. When your design is ready for testing, I for one, will be more than willing to "buy and drive" to test it out.
If I might offer one suggestion: I have a '75 Mark IV that has a loud, irritating buzzer that goes off when the engine overheats. I would have put it on the oil side of the circuit myself, but Lincoln didn't have the benefit of my experience.
Instead of, or along with a warning light, I might suggest an audible warning system like the Lincoln's. It would be unobtrusive for judging (though that is not a concern from my point of view) and attention grabbing for those who do not scan the dash without fail like my Father.
Just a thought....

Jim

I had my brakes done last spring due to leaky BTV. My mechanic sent the BTV to a well recommended rebuilder in Florida. So far no problems.

Can I suggest your enquiry be broaden somewhat to see if the cause of the problem is in any way the skill of the rebuilder? I'm not mechanical so do not do my own work, but I notice that many members do do their own work. Locally at least, some seem to be quite marginal in their skill set. You have to wonder what part skill and experience plays in all this.

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Good point Pat. When I restored a '54 convert I sent the BTV to a local brake shop (Tulsa Brake & Clutch), who sent it off to a "specialty" rebuilder in Dallas. It came back and when installed and bled it had a very stiff pedal for a few days and then no pedal. I took it off and looked inside the fluid reservoir and found about 1/4 inch of blasting media settled on the bottom. I returned it to Tulsa Brake where the owner apologized profusely, sent it back to Dallas and said he spoke with the owner of the Dallas shop personally about the problem. I got it back a week later and it worked fine for the next few years that I owned the car. The owner at Tulsa Brake informed me that the shop in Dallas had one less employee.