The Stovebolt Site Forums The Shop Area Driveline Hydrovac booster

What is the difference between the Hydrovac unit on my 1952 6400 and a brake booster? Rebuilt Hydrovac units seem to be around $500, but a new master cylinder and a brake booster would appear to be cheaper. Either way, how do I check the Hydrovac to see that it is working properly? Brakes is my next project, probably starting in the next few weeks.

Also, the Hydrovac seems to run off the same vacuum source as the wipers, is this a problem? would it help to use a dual-action fuel pump so both can work well? Maybe add a vacuum canister like a modern vehicle?

Hy oldieoldie, to test the Hydrovac you need to have functioning brakes. If you have functioning brakes, with the engine off pump the brake pedal a few times, now place your foot on the brake pedal and press down on it and hold that pressure, now start the engine, if the Hydrovac is functioning properly the brake pedal should move closer to the floor when the engine is started. Hundreds of trucks were driven tens of thousands of miles safely in all conditions with the vacuum source from the engine being shared by the windshield wipers and the Hydrovac. Adding a dual action fuel pump will improve the function of the vacuum wipers, hope that helps.

Oldieoldie, if you need a rebuilt hydrovac unit , I have one I took off my 51 when I installed disc brakes. PM me it will be priced right and will ship it to you.

Thanks to both of you. I have quite a lot to do to make sure the brakes work before I can test the hydrovac, but I'll keep your offer in mind pdlightning.