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Did u use a proportioning valve????? If not then do u notice any rear brake grab at speeds under 25 mph and less than desireable front end dive at speeds 30 - 50 mph ????? Less nose drive at 60+ mph.

For those wanting to know how the Chevy boys do it, read this:http://www.kingsransom.com/powerbrakes.html

In the interest of a fair fight, here's some links to some Chevy forums discussing the T/V. It seems that a proper rebuild with all the required machining to get it all back to spec is paramount, and expensive.( Most of us already know this, I'm just posting it here for the new guys) To me, the answer's clear, just replace it with a more modern one either like Craig did under the column or I did over the column.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/218459/

http://www.chevytalk.org/fusionbb/showtopic.php?tid/197506/post/1510914/#1510914

http://www.trifive.com/forums/showthread.php?p=149375

Some Hudson guy's with trouble:

http://classiccar.com/index.php?option=com_jfusion&Itemid=62&jfile=showthread.php&t=4843

http://classiccar.com/index.php?option=com_jfusion&Itemid=62&jfile=showthread.php&p=102089

I've done the research for you, so you all don't have to. Take it with a grain of salt, as there's people out there who are completely happy with them as well as one's who are not. For the price of having it rebuilt properly, you can have a safer, more modern style of braking system without the little doubt in the back of your head saying "I wonder if all those sudden failures are true??"


Bottom line is, it's your car, it's you life, as well as the life of the person in the other car that you may or may not demolish when your brakes fail. Consider all the facts and act accordingly. When it comes down to it, we can all bicker about the merits and advantages of swapping out to a more modern setup, but there is only one true choice to make, and that is whatever YOU decide to do. Me, I'd replace it with a modern setup and have piece of mind knowing I WILL stop when I need to. A Treadle Vac user doesn't have that luxury, because in the back of his/her mind, the question will still be there...

Mounting the new MC/booster up on the firewall (Chevy, Eric, YDRadio, etc) definitely solves the pedal leverage problem. In my case, I wanted and original look in the engine compartment. Most people do not spot the reengineered pedal unless I point it out to them. Once your muscle memory is trained for the new position, I do not find it a problem.

To each his own.

Craig

Eric -

You wrote:

Quote:
Having had a few TreadleVacs apart to overhaul the hydraulic section and a couple apart to inspect and/or repair the vacuum section, I have to question the need for much machining - unless someone dove in, previously, and really mucked things up. Rebuilding the BTV isn't like rebuilding an engine or transmission.

There is no need to sleeve the hydraulic bore as there is with a conventional master cylinder. Instead, it is the the surface of the piston/plunger that needs to be free of pits and scores. Yet, I doubt if it costs too much to machine a new rod out of SS and transfer the end washer.

Also, the seals provided in the OTC rebuild kits are a good fit to the counterbore - should not require reworking of that bore. Yet, I can imagine where that counterbore might need some light machine work if it scored, scratched or corroded, though such damage should be rare. However, if the die cast hydraulic cylinder/housing is badly pitted, it should be replaced. (I doubt if anyone is machining replacement cylinder housings for the BTV out of billet, yet.)

The only thing I can see that would require machining WRT to the vacuum section would be to reproduce some of the small brass poppets or for minor repair of the die cast vacuum plate. The latter is more likely to require replacement than repair, but it isn't often that those parts are damaged - except from abuse or in vehicles that sat on a piece of bottomland for years.

I've seen mention of extensive machining required in one (external) thread, but with no details - no evidence to support that.

Perhaps there are some things that I haven't run into yet with the Treadlevac, but I've had them completely apart - from stem to stern - and don't find them to be even as complicated as most carburetors (prior to the advent of O2 feedback systems).

Hmm, if I find myself out of work, maybe I ought to look into starting up a BTV rebuild service.

BH. My thots exaclty. The 'sleeveing' that is talked about over at the Tri-5 sites i finally realized they were talking about hte conterbore for the SEALS. But why??? I'm guessing that sleeving is for some other reasons not related to 'cleaning up' the counter bore for the seals. Most likely seals are retro-fitted to the unit that are a different OD dimension maybe.

Also note that at the tri-5 sites 2 or 3 have indicated problems with units from "Qualified and Reputable" BTV rebuilders that required 3 send backs to correct.

I believe we can get to the bottom of this BTV problem. Maybe no solution to the BTV itself but at least understand the problems that seem to go beyond and thru secular rebuilding attempts.

T'Packman writes "It seems that a proper rebuild with all the required machining to get it all back to spec is paramount, and expensive."

SURE! And here's another one of my questions that no one will like but i'm gonna ask it anyway:

WHAT the fuck are OEM SPECS ??? WHERE are the OEM specs???? WHO has them????? e.g. Is there some genius out there that has OEM specs for the rubber compounding in the compensator port seal???? The spring??????

And apparently all of the "Qualified, Reputable", christened, confirmed, washed in the blood and dyed in the wool "Professionals" don't have the specs either or there would not be so many reports of returns due to failure.

Of course, everyone is installing their BTV's the wrong way now arn't they????? Couldn't possibly be the rebuild!!! Oh dear, not at all.

Keith -

The seals that came in new, repro overhaul kits that I obtained from Kanter and others required no reworking of the counterbore. The rubber cup seal looks to be newly manufactured. The leather seal could be an off-the-shelf item, but I never looked into that.

As such, I personally see no reason to machine the counterbore except for damage, but - never mind scratches and scores - I haven't even found corrosion in the counterbore of any of the units I renewed that would require machining. Cores from field cars might be a whole 'nuther story, though.

If a rebuilder is modifying the counterbore to accept some sort of other seal, it seems to me that they made too much work for themselves - unless they have darned good reason for a seal of alternate design. If so, I'd like to know the whys and wherefores.

Personally, I've had no problem with the repro rubber seals, but would like to hear if others have.

It's still all a moot point, the unit is useless and unsafe. It's cheaper and better to replace it with a modern brake unit, it's as simple as that.

Eric,

Although we've drifted a bit off-topic, you brought up the amount and expense of machining as a point against rebuilding the TreadleVac. I must admit that I didn't follow all the links that you provided, but I don't see where anyone out there in cyberspace has come forward with details to support that point. Therefore, I'm reasonably questioning how much machining is truly "required".

Yet, I fully agree with what you later wrote, that:

Quote:
People need to make a fully informed decision, but the problem is that people don't (yet) have all the facts that they're looking for.