">Diesel engines don't produce their own vacuum and need a pump to accomplish vacuum power. The stock SD-33 diesel engine has a vacuum pump mounted on the back of the Hitachi alternator that is not very powerful, and isn't operable. The previous owner (PO) installed a GM Alternator in another location and the engine is running both. With a Hydro boost conversion the power brakes tie into the power steering pump, are more effective and allow you to free up engine power.
Parts can be had at any u pull it, and an early 90's Astro Van is the preferred donor vehicle.
-Note if your scout/ vehicles power steering pump & steering gear has flared fittings you will have to change out hose ends or buy adapters to fit the O-ring type hydraulic fittings that GM used on all of there vehicles from the early 80's on up.
If your scout is circa 1980 you will have O-ring fittings and an easier install.
Parts list:
Astro Van
-Hydro boost
-Master cylinder
-Proportioning valve
-hydraulic lines connected to booster
-brake lines extending from the Master cylinder to the ABS
Decided to tackle this project as the examples from binderbulletin.org
made the project appear easy. This project has proved to be relatively
complicated. Learned how to flare brake lines which is a must for this project.
The other time consuming aspect was dealing with the longer shaft of the hydro booster.
some people section the rod that connects to the pedal while others build a plate to mount the booster farther back from the firewall. I chose to create a plate, and adjust the brake light switche. Other conversions used some sort of spacer that backs the booster 1 inch from the firewall. Cutting the stock booster bracket and welding it to the Astro van donor booster is the best option IMHO (in my humble opinion).
I didn't want to use a welder and it has ended up costing me more time and money.
Had a great idea of fabricating an aluminum spacer, but made it to thin and didn't complete the install before the weekend climbing trip to Smith Rock and had to give gas money to buddies.
After working past 4am plumbing and installing the brakes waited till the next morning to bleed the system and wouldn't you know it the rear master cylinder plug cross threaded and refused to seal letting air in the system.
