Okay first a little background: I plan to to a diesel conversion on my Land Cruiser, and while in the process, I planned to do a hydroboost conversion as well, knowing that I can't use vacuum boost with a diesel. Well my brake booster just took a dump, so I figure instead of rebuilding it or blowing the money on a new part, I'd go ahead and plunge forward with the hydroboost conversion. I've got a few questions though, that I figure you guys would be able to help me with.

First question is, what differences are there among GM hydroboost units? What should I look for to make sure I find a unit that's still servicable, and are they rebuildable? If so, who makes a rebuild kit?

Second question, I have larger calipers up front, which required upgrading my master cylinder to one with a full inch bore. What disc/disc or disc/drum GM vehicles used a MC with a full inch bore? Right now my brakes are disc/drum, but hopefully soon I'll be putting discs on the rear. If I can find a MC with a replacable residual valve on the rear line's fitting, that'd be awesome. Another important factor is that the fittings be on the left side of the MC, since my factory hard lines aren't long enough to extend inward to the right side of the MC.

And third (sick of me yet?), my power steering system (I'm told that the hydroboost runs off the PS pump) uses ATF instead of actual PS fluid. Will the ATF hurt the hydroboost unit at all, or is it kosher?

I would snatch a "true" 1 ton Chevy diesel Hydroboost system ( 82-87 years ) because I know they have a 1 in. bore MC. ATF just goes to higher temps but you could put a tranny cooler on it to help. You will have to modify the hard lines you already have but you know that.....Good Luck

Grab the latest hydroboost and m/c you can off any 1 ton GMC truck. The m/c bore will be between 1 1/14 and 1 5/16ths. Trust me when 1 inch would be way too sensitive. Atf fluid is fine. There's no good rebuilt kits available anymore. If it's bad I rebuild them for 180.00, kit from me is 75.00. As far as left hand side, doubt they're any like that, buy new lines.

Dont think you will have a problem finding a chevy MC with the fittings on the left side. I do wonder about the fitting size though. Metric/standard.

Dont think you will have a problem finding a chevy MC with the fittings on the left side. I do wonder about the fitting size though. Metric/standard.

Yeah I'm counting on having to cut the flares off the ends of my lines and put standard fittings on. Not a big deal though, since I have a set of brake line tools that I bought to work on my project VW (which oddly enough, have only been used on my Toyota) :D

So any 1-ton hydroboost unit is a good way to go the, eh? I just got an offer from another guy here for his hydroboost unit (not sure if he's including the MC) from an '84 diesel truck that I'll most likely take him up on if I can't find anything at the junk yards here.

Grab the latest hydroboost and m/c you can off any 1 ton GMC truck.

For a given year, is there a difference in the 1/2-3/4-1 ton hydroboost units, or are you recommending the 1-ton setup because of the M/C?

Pete

For a given year, is there a difference in the 1/2-3/4-1 ton hydroboost units, or are you recommending the 1-ton setup because of the M/C?

Pete

Slight difference between the sizes, but insignificant. I actually reccomended 1-tons for a silly reason. Lots of you guys go from truck to truck at pick and pulls. You have better odds of finding one on a 1 ton;-)

When I said late model I meant 2000+. Hydroboost last 15 years or 150,000 miles on average. A lot less if ATF fluid wasn't used. Something in 1984 is bound to be bad or going bad.

Slight difference between the sizes, but insignificant. I actually reccomended 1-tons for a silly reason. Lots of you guys go from truck to truck at pick and pulls. You have better odds of finding one on a 1 ton;-)

When I said late model I meant 2000+. Hydroboost last 15 years or 150,000 miles on average. A lot less if ATF fluid wasn't used. Something in 1984 is bound to be bad or going bad.

I just took a guy up on a 1-ton out of an 84 with the MC and hydro lines for 75 bucks. I hope I didn't jump the gun. I'd feel like a jackass to reneg after telling him I'd take it...