'65 D1200 Hydravac

[MarkO]

Hi all,

my '65 t-all has unboosted drum brakes on all four corners. They are more than adequate for the job at hand but could use some help some of the time. It would be particularly helpful when I have one of the trailers on behind.

The long term goal is to update the axles to some 8-lug axle in order to get rid of the big 6-lugs that I have currently. And updating at that time to at least front discs would be really nice.

In the short term, I would like a little more stopping power.

Does anyone know if the booster used on the 1/2-ton was the same one as the boosters that were installed on the 3/4-tons?

If so I have a line on a used one from a 1/2-ton with brackets for a reasonable price. If not I have found a vendor that has rebuilds on the shelf at a reasonable price.

Thanks for your input.

 

[Michael Mayben]

You talkin' an old-fashioned "hydrovac" that mounted under the floor (some were on the firewall) with the integrated single channel master cylinder or a "mastervac" like used on later fullsize and Scout II in either a single diaphragm or dual diaphragm boost with a separate dual channel master cylinder?

I'd totally put any "hydrovac" system out of my mind, way too expensive and touchy to deal with. And those integrated masters are single channel only which don't come close to working with more modern brake sets that must use either a combination valve (drum/drum) or proportioning valve (disc/drum). And they sure won't produce enough boost to light off a disc/drum master cylinder brake set that runs about 1800psi line pressure in full push.

A dual channel "mastervac" will clamp down any disc/drum setup you will ever bolt onto the rig.

But the easiest setup would be to adapt a true hydroboost setup that are dirt cheep in boneyards and also as remans. Something for a Ford f450 from the 80's, a massive amount of boost/line pressure just as is, no need to hop 'em up in any fashion. But ya must have a ps pump that can push one that has dual returns, the companion Ford ps pump would be an easy adaptation as well.

The bracket fabrication is fairly routine.

I know you didn't see doc morgan's '66 t'all that we've done the motor and tranny on recently (with the gearvendors od into a NP205) at the IHSTO xmas dinner. But it has a late model IH dual diaphragm mastervac setup on it with a two channel master cylinder and late model d44 axles with drums. He hauls a big airstream and also a car trailer all over the country with it and it stops yesterday. That was all a bolt-on deal done by jcf down in coos bay a few years ago. I should have taken pics of that yesterday when they stopped by for some carb tweeking on their way home from the pardee.

 

[MarkO]

What I was thinking about was the hydravac unit that goes inline after the master and before the split going to the front and back. On the '65 pickalls it was mounted on the driver's side inner fender above the steering gear.

Most of my experience with 'binders has been with medium duty trucks and buses. As a consequence I am fairly familiar with the vagaries of the hydravac.

Yes I know a dual system is better but with a four speed dealing with the clutch part of the m/c is difficult. And I am not in a position to add an automatic at this time.

Since I don't have power steering a hydroboost off of something like an f-450 wouldn't work either.

I did see doc morgan's t-all and it is a very sweet ride--automatic, power brakes, power steering, a/c, and a very nice paint job. And I talked to him about what he was going to do with his old hydravac, hence the question about whether or not the same unit was used on 1/2- and 3/4-ton pickalls.