I am slowly getting the maintenance and repair done on my '62 F600. Today I found a cracked hose running from the Hydravac unit thru the floor and into the cab behind the driver. After replacing the hose I started the trunk and noticed a vacuum noise coming from the end of the hose inside the cab. When I step on the brakes the noise goes away. Is this normal or is there a problem somewhere?

 

Vacuum noise through that is normal. However, it should just be when you apply and release the brake, not all the time. It is the "atmospheric breather", which allows air to move in and out of the chamber when the vacuum moves the diaphragm. Illustration, of sorts:

http://dave78chieftain.com/Hydrovac/prior-engine-b.gif

So if you have vacuum all the time at that vent, something is wrong wrong wrong. .

 

I thought so.