Figured I'd share this tech with you guys.

1988+ Chevy S10 Napa # 20874

The GM pump is a higher output pump the only difference between the two is the input fitting. The one that comes on the S10 pump is straight while the one on the ZF pump is a 90. I ended up pulling the fitting out of a rover pump (it wasnt easy they are extremely fragile took 3 pumps) and then using a small hammer and piece of wood to help tap it back into the S10 pump. Then you have to pull the pulley mount off of the ZF to install on the GM pump. a 3 jaw puller or crows foot puller should do the trick. Do not use a 2 jaw puller or you will break the mount (I also broke 3 of those) Lucky for me I had a bunch of pumps around and only had to buy one spare. Here is where I am at right now - GM pump with new fitting.



Here's another link on how to turn up the pressure and flow even more. powersteering for ram assist. This could also run a hydraulic winch or hydro assist brakes. I should note if you're not sending the additional pressure to something other than your steering box you will likely blow your sealsin short order.

 

Good write up. What have you done with the hoses? Most are crimped so it's not like you can easily make your own. Did you just buy a new set?

 

All of the hoses are a direct fit if you change the input fitting to a 90*(which is what I did to make things easier) You would also have to do this if you have a 94-95 disco or any engine with a dizzy. If you leave the straight fitting on the s10 (96'-99' gems engines) you will either need to put a spring in the hose or splice in a 90* fitting to route it the right direction or keep it from collaposing. You will need 3' of 5/8's hosing because the stock hose wont fit. You dont need anything super fancy for the input hose because it's low pressure just make sure it's high quality reinforced hosing.

 

Good info, but I was more curious if you replaced the lines too and tried to do something custom. Also, did you use ATF or PS fluid? Any whine? Feel different?

 

I havent had time to finish it yet but hopefuly I will get it done tomorrow or Wednesday.

Any hydraulic shop around you should be able to make custom high pressure lines. My lines are fine and fairly new so I figured I'd leave them as is for now. The low pressure hose is fine the way it is. The guy on dweb who was talking about splicing in some copper tubing which isnt a bad idea but I dont see the need for it and it's two more potential places it could leak.

I plan on using power steering fluid because the guys who have done this swap have said it whines with ATF and the info says to use power steering fluid anyway.