Re: Questions re Universal power brake booster.

Posted by BH On 2009/9/22 8:05:47

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.