I have a Hydroboost on my half ton GMC. Works well.
I sourced the unit off of an Astrovan in the junkyard - was about $15 about five or six years ago. I ran it for a while with no problems, but recently put a rebuild kit in it from Pirate Jacks (about $50)
The accumulator on the Astrovan Hydroboost is good for about two stops without the motor running. It'll stop without the booster, but it requires quite a bit of pedal force.
Mine is mounted on the frame rail on a bracket I bought off of ebay that the Hydroboost attaches to. The unit connects to the factory pedal set via a rod about 15" long which puts my brake master under the driver's seat. The brake pedal arm was modified to have the correct 'pedal ratio' for a brake system with a booster. I also shortened the pedal in the cab to make it a bit more 'ergonomic'
I run a GM 'ham can' power steering pump with an extra fitting welded on the reservoir for the return from the Hydroboost. I converted all the fittings on the Hydroboost to JIC/AN so I can use regular hydraulic hose/fittings.
