The Stovebolt Site Forums The Parking Lot Big Bolts Building a better Hydravac

I'm about to tackle the brakes on our 1950 6400.

It looks like everything is shot - so I'm going to tear everything off and start from scratch. Currently, the plan is to put things back together "stock looking" , but I'm looking to those of you that have done this before for advice.

Since I already have to buy a new master cylinder and Hydavac and lines and wheel cylinders, does anyone recommend a particular one over another? Is there a particularly great master cylinder or Hydravac to find, or is the stock replacement stuff at my local Napa Auto Parts dealer gonna do a good job?

If you wanted to update the brake system, but still have a Hydrovac, then take a look at the catalogs at NAPA.
They offer (original for other model vehicles) newer style Hydrovacs.
You may want to swap to a dual circuit master cylinder, and use dual Hydrovac, this was standard practice on a number of vehicles.

A cheaper simpler solution would be a dual circuit master cylinder with attached booster, still mounted under the floor.

Grigg

I think a 2 reservoir master is a good idea. I redid my brakes, rebuilt hydrovac - the master cylinder is kind of spooky, its so small. But I will say its got the best working brakes of any antique I have ever had. Like I said, some up grades Iam sure would be good, but the old system will surprise you - atleast it did me. Good luck with yours.

Will any of the newer Hydravacs and dual resevoir cylinders bolt up to a 59 Viking 60 where the master is under the floor?

A Hydrovac as I understand it is a remote mounted brake booster. It hangs on the frame wherever you want to put it, this system uses an ordinary master cylinder in the stock location.
If you had a dual Hydrovac system it would be two identical Hydrovacs usually mounted side by side on the frame fed by an ordinary dual circuit master cylinder.

To upgrade a truck that originally had either no Hydrovac or only a single one to now have dual Hydrovacs will involve finding a dual reservoir master cylinder with the proper bore and making or finding an aftermarket bracket to mount it. You may luck into a bolt on replacement dual circuit master in the later years, I'm not sure.

I think if you are going to update the MC and booster and no longer be original then a better solution than using dual Hydrovacs is to use a more modern master and booster bolted together as a unit. This will be a more reliable and cheaper system.

Even better yet though. If you already have a power steering pump then I highly recommend a hydrobooster, it is small, compact, powerful, and works off the PS pressure. I have had a few Hydroboosters, and really like them, doubt I ever use a vacuum booster again. (But they are not recommended for drum only brakes on a small vehicle, larger trucks are OK with drums though.)

Grigg

Jim, you Left-Bankers (Californians) think bigger than this mid-westerner, and Grigg is clearly one of the biggest thinkers - and do-ers! - of all. But I'm wondering what your ultimate goal is for this truck, and why you're contemplating a complicated procedure. If you have the original (but maybe shot?) hydrovac, why not get it rebuilt? I think rebuilding all the brakes (pads, cylinders, master, lines, etc.), and the hydrovac, AND, making sure the emergency brake functions properly, would be sufficient for a truck that shouldn't be driven that fast to begin with.

Of course, California isn't as flat as the Midwest, I'll grant you, and I know modern traffic can be challenging. But I put more faith in a simple, but reliable system, with appropriate driving habits, then in more modern but complicated technology that still can't overcome poor decisions.

This, however, is the opinion of a guy who, after 4 years of driving into and out of the same garage behind his house every day, managed to back into a tree next to the driveway. (it was dark, and raining . . . and, and . . . REALLY foggy . . . yeah . . . that's the ticket!)

-Michael

Jim,
You might want to consider how much driving you intend for your truck or what kind of loads it will be carrying.
I feel the stock brake system functioning like it should is enough brake for your truck, but then you didn't say how you intend to use it.
I'm doing brakes on my 2ton and cost is coming into play and if you add it up it will be easy to well exceed 1000 dollars just for parts.
Now if money is of no concern then I would put on what ever tripped my trigger.
I drove my truck home when I bought it not knowing the rears were froze up and did ok with just the fronts working, so i know this thing will stop just fine once the whole system is working.
With a six series gear in the diff I can't go to fast anyway
Dan

I just replaced the original hydro on my 48 this year and it cost my $280.00 with a core. I wanted to buy a new style since I was sure the 48's style was no longer available. Since I didn't have a core (they have to be the same hydro as the new one to be accepted as a core) it would have cost me nearly $400.00, just for the hydro-vac. I definately wouldn't install two for that kind of money. My other 48 has a dual res master with a booster mounted under the floor. Total investment was only about $50.00 for the new master. I had a good used booster and fabbed up my own mounting system and replumbed it myself. This truck has twice the braking power with less effort over the original one. In my opinion, do a booster,
Scott