Peer Pressure is squirrelly. Suspension mods installed by the previous owner make the ride stiff; at highway speeds expansion joints and large bumps render the steering vague as the body floats up over the springs and back downward. Braking has gotten dicier since I bought the truck. Moderate pedal pressure these days sends the front and rear in different directions as the pads and calipers grab at different points.

Among the many repairs and upgrades I’d like to do is one of the (I’m told) easiest and most inexpensive improvements to the braking system: the Hydro-Boost. A system originally installed in GM products the world over, it’s an improvement on the old big round booster design Scouts were installed with, because it does away with vacuum-powered braking in favor of fluid power supplied by the power steering pump. It seems to be a pretty popular mod for a lot of vintage cars. Following a thread on the Just Internationals forum, I ventured out to the junkyard with my brother-in-law in search of an Astro Van with ABS brakes. We found four with and two without—the difference being the ones without ABS have the big round brake booster we’re looking to discard. I found an ABS Pontiac Safari already propped up on tires waiting for me, so early this morning I got to work.

Hydroboost 4

I disconnected the hose running across the top, then the right-side hose that ran to the power steering pump. Thankfully, someone had already pulled the radiator, so I had a ton of room to work with.

Hydroboost 1

The left-side hose running down underneath was very difficult to get off (I didn’t have metric wrenches) so I punted and cut the hose as close to the top of the metal line as I could. I used a pair of channel locks to snip the coiled metal hose running to and from the ABS computer (the big box directly below the hydroboost assembly) below the proportioning valve because those bolts were not coming off for love or money.

Hydroboost 2

Finally, I crawled inside and used a long 15mm metric socket to take off four mounting bolts on the bracket. Hopefully other used Astros will be cleaner under the dash than mine was.

Hydroboost 5

Then, a bunch of wrestling, tugging, pulling, and twisting got the whole assembly free. GM didn’t leave a lot of room in the engine bay to work with, so I removed the top fitting to clear the cowl and put it back on when I was done.

Hydroboost 3

Stay tuned. Next I’m going to assemble all the parts needed to retrofit the assembly.

Date posted: March 11, 2013 | Filed under Hydroboost, Progress, Purchasing | 4 Comments »

4 Responses to Hydro-Boost.

  1. Eric says:

    Hey – just a thought, cuz I am doing the same thing (but I bought a made kit from….The reason I am doing the hydroboost is because my alternator doesn’t charge a thing and I want to be able to put a “normal” and higher amp alternator on….I wasn’t going to do it yet, but I also got a power steering pump – once I realized what a pain in the arse it is to get to the alternator, I decided to change it while everything else was out of the way……

    Just something to think about when you get that far :)

    I am planning on getting the bolt on rear brake kit too….

  2. Eric says:

    SO, the alternator is more of a pain in the ass than anything…..needs an adapter bracket – i have neither the time nor skill to make one. I had one ordered from Anything Scout, but after two weeks, I called and he hadn’t even started it…..I finally got the alternator, but can’t do much with out the bracket….looks like I may have to call him back to get one made….sucks.

    Still love my scout though :)

    By the way, I live in North East MD, we should meet up sometime :)

  3. Bill says:


    Check your email! I’m trying to get a group of IH owners together in early May. We’d love to add you to the group!

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