brake conversions problem

[John Hertog <crossram@xxxx>]

Hi to all,
Jeff e-mailed me this, it should have gone to the group instead. It
really pertains to disc conversions on 300J's and ram 300K's, and I am not
at all familiar with the remote booster system . Anyone having any
suggestions as to how to eliminate Jeff's problem, please e-mail him back
directly at mr-320@xxxx or send back thru listserver. . Thanks.
John
======================================================

----- Original Message -----
From: "jeff shenk" <mr-320@xxxx>

> john;
> there is one thing on the 63-4 disc conversion that you havent
> touched on andits a biggie, its the problem of the remote booster
> [hydravac] sucking air at zero backpressure.
> when i converted my k to discs, i took the residual pressure
> valve out of the m/c and tossed it, as discs require zero backpressure
> to keep from having a very heavy drag. since this was, by a long shot,
> not the first disc conversion ive done, i elt quite confident, not
> realizing that it WAS the first one with a hydravac, i never gave it any
> thought at all. i did have a bit of difficulty in the initial bleeding,
> getting all he air out was tough, couldnt figure where it all was coming
> from, but finally got it done and went to take it on a test ride. the
> test ride was exciting to say the least. the first 3 times i pushed the
> pedal it was fine, then it had 1/4 free pedal, then 1/2 pedal, then it
> just barely was there and i turned around to come back and it had zero
> pedal, no brakes at all. did manage to get back safely, it was fun, and
> a careful post mortem showed that the h/vac was sucking air at zero
> backpressure and gradually filling the line with air. i got a kit and
> rebuilt the h/vac and no joy, it still did it, seems to be a built in
> problem, the h/vac needed backpressure to keep the seal, just like the
> w/cyl cups that the residual pressure system is designed to keep sealed.
> i never got the problem really fixed, the drag didnt seem to
> affect mileage and it didnt bother me at all, except to be sure to run
> lifetime warranty pads for cheaper replacement costs as i was only
> getting 4000 mi/set of pads due to drag wear. when i parked the k in 93
> or 4 it was one of the things that needed to be fixed before it hit the
> street again.
> it hasnt hit the street and hasnt been fixed, any suggestions
> would be very much appreciated as im about ready to finally build an eng
> for it and put it back on the street.
>
> JEFF
> tucson az.
>