Problems after hydro-boost rebuild on 1994 K3500
 

Hey all, I just did a seal replacement on my truck's hydro-boost system as it was leaking power steering fluid. I did the figure-8 seal on the back, the cylinder seal, and the o-ring on the accumulator because that's where the leak was at. Now, it's acting funny; after replacing the seals and buttoning everything up, I took the internet's advice and started it up, then turned the steering wheel from stop to stop 4 times. I got a little whine from the power steering pump, so I topped it off and did it again. No problem. Then I stepped on the brake. The brake went almost to the floor and did a little "kickback", and suddenly turning the steering wheel was very difficult, like the power steering wasn't working. There was a hissing noise as the brake pedal slowly came back up, and the steering went back to normal. I shut it off and went looking for leaks. There was a little fluid coming out of the hole just below where the master cylinder joins the booster, and lots of foam in the power steering reservoir. I let it sit for an hour, and did the tests again. Steering was great, but still getting the pedal kickback. Shut it off and left it for another hour, and still the brake pedal kicks back, and the steering is stiff again, but not as bad as last time, and the brake pedal depresses itself when I turn the steering wheel.

What could be going on? Please don't tell me I borked the cylinder seal, I need to drive this to work tomorrow. Or is it something else?

OK, I took the day off from work, and tackled this again. The internet tells me a sure way to bleed a hydro-boost is to turn off the engine, jack up the front end of the truck so the wheels are off the ground, then run the steering wheel from stop to stop 5 times, then depress the brake 3 times, slowly. Repeat at least 50x. OK, I did that, saw some bubbles come out, thought I was clear. As soon as I started the engine, all the fluid sucked out of the reservoir and was replaced by foam, and the pump started making a god-awful racket. I shut the engine off and left everything to settle for ~15 mins.

I came back to a full reservoir with only a few tiny bubbles showing. Did the steering wheel 50x dance again, same thing. I went looking for leaks and didn't find any, but I pulled the hose with the flare nut (I don't know which one it is, and I can't find any diagrams anywhere that tell me which is which, ugh) and found that the o-ring seal was shredded. Odd. I found a suitable o-ring in my seal kit, installed it, and tightened everything snug. The other flare-nut hose still had an intact o-ring, but I couldn't find a replacement in my seal set, so I left that one alone. Just out of curiosity, I started the engine briefly. No whining from the PS pump, but I still get the same brake pedal kickback. "Wonderful", I thought, "now I just bleed it and it'll be even better". Wrong. Once again, I did the steering and brake pedal jig with the engine off. Then as soon as I started the engine, the fluid sucked away to who knows where, replaced by foam and a howling PS pump.

None of the hoses have leaks at the usual suspects, so I conclude it could only be two things; the flare-nut hose that I didn't replace the o-ring on, or the return hose, which is attached to the hydro-boost with a short piece of hose with a hose clamp. The original hose clamp was one of those self-destructing types that requires a special crimper mechanism that I don't have. I replaced it with a compression type, but maybe that's not strong enough, maybe I should use one of those screw-tight kinds?
I'm stumped and I need this vehicle to get to work, and I'd rather not spend the multiple hundreds of dollars to take it to a shop. Any suggestions?