Ok this is gonna sound a little ridiculous, but how unrealistic is it to think about hooking up an electric/hydraulic pump to operate the PS box? Would it work? I was wandering the junk yard the other day and they had an old bus with an electric/hydraulic wheelchair lift. The PS pump only pumps one direction, so if plumbed correctly this should work right? How much pressure does a v belt drive PS pump put out VS an electric on like this wheel chair lift?

 

It will work, because as you said the P/S pump is just a hydraulic pump. You will probably need a resivour and adjustable pressure regulator. Depending on the size of the pistion the pump drove it should work.

However, hydraulic pumps require alot of amperage to operate. The load you take off may not equal the load your putting back on the alternator. So while is should work, it's probably not worth the effort, but I would love to hear differently so don't let me stop your experiment.

 

my honda hatchback has electric power steering, they free'd up some hp off of the motor by making it less a drag on the motor. it works pretty good.

 

You could look around online, and maybe find what the power draw from a wheelchair lift is (seems you can find anything on the internet if you look hard enough). You'd probably need a higher amp alternator no matter what the drain is.
Keep us all updated if you decide to give it a shot! It'd be cool to find out if it'll work!

 

I'm def gonna be running a highamp alt, because I have an elec fan and WP too. Hmmm. That's a lot of electricity in this old mud truck. Is this thing a hyrbid LOL????

 

I dig the idea, and really like the fact that you came up with this though while cruising the local salvage yards. I tip my hat, and my beer to you. You should be commended for your idea. Cheers!
A real plus is that the steering will still be assisted while the engine is off. Could be a good thing if one would stall on a hill.
Now for the bad news;
Honda first developed an EPS system back in 93, and used it on the NSX. It worked well, but only because it was used to vary the hydrolic assistance it offered. A vehicle at higher speeds requires less power steering assistance, than one at lower speed. Since these are brush type DC motors, they tend to wear brushes very badly at higher RPM's and have very high comm. to brush friction. This would limit its use, and performance in a heavy vehicle. With no way to slow the motor down, it would be running all the time, and burn up in a very short period of time. See the wheel chair lift only goes up and down and the motor only runs for a very short period of time.
One option would be to use a switched reluctance motor, but trying to develop some sort of proprietary current wave-shaping technique to mitigate torque ripple is dificult, and expensive.
Another option would be a brushless permanent magnet motor, but once again we are getting very spendy, and the current draw would be very high,(although not as high as a rare earth magnet type, but still high) and require a stout electrical charging system, and would draw more horsepower than one would save by just using a hydrolic belt driven pump. Delphi has been trying this for a while with thier EPS systems with less than stellar sucess.
A final option might be AC induction, but seriously,we are getting way out of hand at this point. This is probably not going to be a do it yourself type job, trying to configure a variable speed controller that used throttle position and speed input to regulate the speed of the pump so we can control the fluid output. I guess it could be done, but is going to take a few more beers to get that job done.
I am done now, as you can see, I have thought about this once or twice, and I am glad I am not the only guy with this stuff rattling around inside the old coconut!

 

It's only gonna be makin a few passes (four-five max) 6 months per year.....(totalling between 24-30 per year) I think the old cheap junkyard one is good for that, as long as it does power it well.

 

The lift is working off high pressure and little volume and is operating a ram vs. your ps. pump is working off lower pressure and volume. Big difference. There is more about hydraulic stuff in the 4x4 forum.

 

An AGR 'high performance' PS pump flows at around 1500 PSI and 3.5 GPM. That can't honestly be that far from a 1700 PSI/3.1 GPM elec pump(which I found new for under $200). Really thinking about buying it, I'm sure it will work.