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View Full Version : Scout Man's $50 Hydro Boost Conversion



scout man
April 6th, 2010, 09:06 PM
It isnt finished yet, but I figured I would start a writeup on the process, mostly because I cant beleive how cheap this mod can actually be. My goal when I started out today was to buy a Hydrobooster from a Chevy Astro van, along with the matching Master Cylinder, proportioning valve, power steering cooler, and all hoses I could snatch up with it.

I started at Pull and Pay in Aurora, and I am not sure I will ever go back there again jsut because they pissed me off. When they drained the fluids from the vehicles they tossed all the caps to all the reservoirs. Not a single vehicle in the GM/Chevy section had a cap of any sort on any reservoir. I asked if they just had a pile somewhere, and no, they dont. I told them that was rediculous and I would spend my money elsewhere.

Drove across town to Western Auto Recycling where I had much better luck. They only had about 3 astro vans on the lot, and all were vacuum booster, but I finally found one lone hydro unit on a chevy silverado (late 80s?). I pulled this one, although it was not easy to release the linkage. Had to remove the steering column and tear out a significant portion of the dash to get to it. I also claimed the reservoir and the proportioning valve from this truck. Then I grabbed a cooler off of a Bronco II. Total price? $36!!!!! The rest of the money was spent on 2 hose couplers (should only need one), hose clamps, and 4 bolts.

In order to make this new booster fit there is some significant mods that need to be done. First of all, the push rod on the new booster is about 8 inches longer than the stock scout one. I had to shorten this a bit, as well as add a spacer onto the mounting bracket. I had to cut this anyways, as the eyelet on the new push rod was significantly larger than what I needed, and it would introduce slack into my brakes. Cut the new rod to length, and welded on the eyelet from the old booster. I realize some people will turn there nose up at this, but there is just no way around it. It is welded solid and it is a straight line force that will be applied anyways.

Next, there was an issue of the new hose fittings having an o-ring style fitting, while the scout parts have flare fittings. Solution, cut the o-ring fitting off, flare the metal tube, and recycle the old fittings from the original scout lines. Only two ends needed switched over. This was no problem and both ends re-attached with no problems.

I will have pictures at some point, but my hands were just way too greasy to touch anything. The way this works is the pressure line comes out of the pump, into the booster. There is then a high pressure line that comes out of the booster and passes onto the steering box. The low pressure returns from both pieces will T together (T was already on the line from the silverado), then enter the cooler, then back into the pump reservoir. And that is really all there is to it! I will finish it tomorrow and see how it actually works.

Notes: I decided not to replace the proportioning valve for now, as the new one seemed to be the same as what I have already, and I think the brake lines are going to round off when I try to remove them, so I will avoid this if I can. Also, as of now I am not increasing the pressure in my PS pump. If I do not receive enough power, then this is always something I can do in the future. I will post some pics tomorrow and the finished results.

ROKTAXI
April 6th, 2010, 09:36 PM
I also did this. Love the hydroboost set up!! Had to go to a company in GJ that had all the various fittings and hydrolic lines to make it work. I went with a reman hydroboost from a specialty shop back east (Missouri?) and they provided me with a new M/C to match. Don't recall all the details of the installation but after some minor trial and errors, it works great. Best thing about it (and the reason I went with it) is high altitude braking. No more fading vacuum booster.

scout man
April 6th, 2010, 10:35 PM
yea, my brakes suck, really bad. This was a conversion out of necessity. This actually wasnt even on my radar at all till I drove a scout the other day that had the conversion done (he spent $200) and i was blown away. It quickly went to the top of my list of projects. I think the reason I had never considered it was because of this... http://www.anythingscout.com/part/3117-hydroboost-kit-for-scout-ii ... which was really my first exposure to it. Needless to say it wasnt in the budget, but I think my route was just about the right price! In fact, the unit I got looks almost exactly like this, and even the one in the kit would need the same modifications I did to mine. I am really looking forward to getting it all buttoned up tomorrow and see what the results actaully are.

Brody
April 7th, 2010, 07:04 AM
Nice Steve! When you get this finalized and your hands clean, stick it in the IH section if you would. Here, too, but it would be nice to have the Tech part in the IH section, too.

scout man
April 7th, 2010, 10:00 AM
Will do Pete. If it wasnt for this dang snow it would be on its way right now. :mad:

scout man
April 7th, 2010, 07:17 PM
It works!!! I may need to go back and boost the pressure in the pump at some point, but I will give it time to finish bleeding out first and see how it does. braking works great, turning right works great, turning left when at a standstill gets a bit under powered and jerky. However, both directions were doing that at first, so it is possible there as a small air bubble in there somewhere. I was worried with the brakes at first, as they were doing really weird things, but after bleeding them they worked great! Not seeing any leaks yet either, which is good since there are a lot of hose connections. It will now lock up all 4 tires without too much effort. Here are a couple pics. There is really just a mess of hoses.

Here is the PS cooler. I managed to squeeze it in behind the driver side headlight.
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Here you can see the extra inch or so of spacing I put in between the firewall and booster.
11344

And this is just the mess of hoses down by the pump and steering box.
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WINKY
April 7th, 2010, 08:45 PM
i got hydro boost on brutus, works like a champ power braking when needed.

Just word of caution you lose all brake assist if the engine is off or dies. (not an easy task to stop when facing downhill/ twin cone)

i do know that its the same with vacuum boost but with hydro its much harder to apply brakes with no boost.

but you will like them!

scout man
April 7th, 2010, 08:58 PM
i got hydro boost on brutus, works like a champ power braking when needed.

Just word of caution you lose all brake assist if the engine is off or dies. (not an easy task to stop when facing downhill/ twin cone)

i do know that its the same with vacuum boost but with hydro its much harder to apply brakes with no boost.

but you will like them!

Yea, I lost my brakes with vacuum boost too when the engine died. At least now I have brakes while the engine is running! Plus, the unit I installed has a Nitrogen cannister on it. I dont know how it works, but supposedly it gives me 3 - 6 pumps of the brake after then engine shuts off. PLus, I already have more brakes even without the engine running. Something about the hydroboost transfers more power than just a vacuum booster even with the engine off, at least it seems that way. Either way, I always make sure I have a functioning e-brake, and I use it on a very regular bassis on the trail (although hopefully a lot less now that I have normal brakes.) But yes, thanks for the warning, I will have to test it out sometime to see what to expect when it happens on a trail.