Advice on hydro boost conversion?

[INSIDIOUS '86]

Looking to do hydro boost on my truck. There is a guy selling a hydro system out of a 73-87 truck on c- list for 80$ http://seattle.craigslist.org/sno/pts/3148331643.html

Is there anything I need to know about the conversion? And what about part numbers for seals and such since I would like to drop in a fresh system

One question. I don't like bench bleeding so can I keep my current m/c or are the two different size? This has an iron and mines aluminum and plastic so I'm assuming this is a 70s hydro boost? Will my current powersteering pump work?
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[v30crewcab]

your master will bolt on. the hydroboost came on 3/4 and 1 tons, which got a cast iron master. should bolt in, if its got the oring fittings on it. the older ones had flare fittings.

[DirtyLarry]

Not all 73-87 hydroboosters are the same. The difference is 1981 and newer hydroboosters have metric fittings (M16 & M18) whereas the older ones had standard fittings (3/8 & 7/16). This is not a problem if you also have a steering gear with matching fittings otherwise you will be either having custom hoses made or replacing the steering gear to match the hydroboost hose ends.

I would not recommend using your old master cylinder. If I remember correctly, my old vacuum m/c wouldn’t even fit the hydroboost unit. Another thing on my truck was that I had to swap the brake line positions at the m/c as the front and rear ports are reversed on the larger m/c vs. the small m/c’s.

Yes, your current P/S pump will work. You can just add a T fitting to tie all of the return hoses together. G-Gans, and P-chassis were plumbed this way whereas the trucks had a dual return ports in the p/s pump. In my signature there is a hyperlink to my NV4500 swap. In that thread is some information on hydrboost as I converted to it while the truck was under the knife for the trans swap.

Regardless, $80 is a great deal for what all he is offering. Go for it! I love my hydroboost and plan on swapping one my Suburban soon as well.

[86c20]

dirty are you talking the p/s lines are diff or the brake lines? just asking to see what is on one of my trucks. also i dont know alot about it but i do now that the diesel guys on 4bt say not to run the returns that way do to back up and not flowing right. better to drill it and weld a nipple on it. not saying that tying them together wont work just passing on what i have read and heard. if it was me i would try it first lol

[DirtyLarry]

I am saying the steering hose threaded fittings in the booster itself is different. The older are standard thread while the later are metric.

Each to their own but running the return lines together is very common and a non-issue. Like I mentioned, even GM vans and stripped chassis ran T fitting in the return lines instead of the double return ported p/s pumps. I have almost 10,000 miles on mine since the NV4500 and hydroboost swap. Not one issue has come up with running them together.

Even some new trucks built today run the returns together. Very common on medium duty trucks with hydroboost and hydromax. This is a system layout of a late model stripped chassis used under most new UPS trucks.

[INSIDIOUS '86]

So where do I get custom lines made if these aren't metric like my 86? And can you tell if the system is an early style by looking at the pic? Also I heard somewhere that hydro pedal rods were different? I'm going to run a cooler on the pump and the engine has a 35% underdrive pulley will that hurt braking?
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[Redcap]

Originally Posted by DirtyLarry

I am saying the steering hose threaded fittings in the booster itself is different. The older are standard thread while the later are metric.

Each to their own but running the return lines together is very common and a non-issue. Like I mentioned, even GM vans and stripped chassis ran T fitting in the return lines instead of the double return ported p/s pumps. I have almost 10,000 miles on mine since the NV4500 and hydroboost swap. Not one issue has come up with running them together.

Even some new trucks built today run the returns together. Very common on medium duty trucks with hydroboost and hydromax. This is a system layout of a late model stripped chassis used under most new UPS trucks.

That is a crazy bong.

[86c20]

well 10000 miles and no problems tells me it works fine then. maybe i misunderstood what they where doing lol. thanks for the info.

you can get hydro lines made at any real truck shop or napa. just need the langth and the ends that are needed.

[INSIDIOUS '86]

Now what if I just ran lines to the hydro boost and not the steering gear?
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[WarBeard]

Subscribed. Need a definite answer on if my stock C10 master will bolt onto the hydrobooster. I hate bleeding brakes.

[bigd65]

If you were around the Houston area, I would trade mine. I want the regular vacuum system

[DirtyLarry]

Originally Posted by INSIDIOUS '86

Now what if I just ran lines to the hydro boost and not the steering gear?
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Huh? Why would you want to do that? Are you planning to run hydroboost but manual steering instead of power steering? I suppose that would work by just bypassing the steering gear. Not sure why you would want to do that unless you are building a straight line race truck.

[INSIDIOUS '86]

Originally Posted by DirtyLarry

Huh? Why would you want to do that? Are you planning to run hydroboost but manual steering instead of power steering? I suppose that would work by just bypassing the steering gear. Not sure why you would want to do that unless you are building a straight line race truck.

Because even on ice I can't feel the damned steering when the front looses grip. With the pump belts off on my truck I can feel the road and drive fine.

When I get a new steering box with a better ratio I will add the powersteering
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[El Campo]

You could always put AN fitting in them too. Have to use the teflon lined hoses but Summit sells all the fittings. I am putting the hydroboost into my 72 and will keep this thread around for the diagrams and advice.

[83 Silverado]

http://www.carcraft.com/techarticles...boost_salvage/
I seen this wright up in Car Craft it may help.

[Hertzdaddy]

You can definitely use your Vac assist master on the hydroboost system. I just got done installing a hydroboost unit from a 79 Diesel c-10 on to my 73 vac assist Jimmy. I just swapped over the boost unit and kept the 73 master in place. No bleeding and the pedal pressure and modulation works fine. I also used the 79 factory t fittings so that works too.

I had a low vac cam on my engine and I really needed the hydroboost. I'm very happy with the way everything feels and works now.

[Billyburban]

Originally Posted by Hertzdaddy

You can definitely use your Vac assist master on the hydroboost system. I just got done installing a hydroboost unit from a 79 Diesel c-10 on to my 73 vac assist Jimmy. I just swapped over the boost unit and kept the 73 master in place. No bleeding and the pedal pressure and modulation works fine. I also used the 79 factory t fittings so that works too.

I had a low vac cam on my engine and I really needed the hydroboost. I'm very happy with the way everything feels and works now.

So you were able to use the vacuum line instead of running a line to the PS pump ?

[craig113]

If you are in the Tacoma area, lines can be made at: Williams oil and filter http://www.wofsco.com/

[Hertzdaddy]

Originally Posted by Billyburban

So you were able to use the vacuum line instead of running a line to the PS pump ?

No, just the master cylinder. The hydraulic lines have to be pulled from the donor or custom made. DO NOT use vac line or even gas line to make them. The rubber on those lines will not tolerate hydraulic (power steering, ATF) fluid.