$135 for a Hydrovac or a vac booster? Just askin coz there's a big difference between the 70's & 50's bolts. The cheapest I could find a new Bendix Hydrovac for my '56 was pushin $400.

If one isn't real particular about keeping it stock, I have seen a couple aftermarket brake systems that use dual m/c & saw one kit that used two small booster cans that could be adapted to our older bolts (cant seem to find that link, sorry).

Or, there's this frame mounted hydrobooster kit for $500

The Napa P/N for the master is 10-57577. I don't have a part number for the Hydrovac. I bought that from a local truck parts facility (Bott's in Woodstock, IL) I do however have a service manual - i'll try to see if they are listed in their and i'll look at my new unit to see if their is a p/n on it.

I got a direct replacement for my 65 C50 wrecker at napa.They had a part #for it and it only took two days to get. I think it was around two hundred with my old one for a core. This was only a year ago. Hope this helps.

Hey guys,

My question is about master cylinders. More specifically are there two on Hydrovac trucks?

I have a single pot under the hood and then there is another master cylinder looking device about 1/2 way down the frame rail (well past the Bendix on the drivers side) the previous owner bypassed this piece while running new lines.

What the heck is it?

Brian,

School buses in the mid 60's used a dual master cylinder with two separate hydrovac boosters. One circuit fed the front wheel cylinders and two of the four cylinders on the rear wheels. The other circuit fed the remaining two wheel cylinders in the rear brakes.

This setup may have been used on bigger trucks but it's been a while since I looked at the diagram.

If there was not a bloody monsoon going on outside right now, I'd snap a photo...

I know where you're coming from. That monsoon lasted three days here in Va. Beach...