I'm in the middle of replacing mine now (850). The Rack Doctor (rackdoctor.net) rebuilds them for $150 including new bushings if needed. Need to turn in a good core. The Haynes manual is lacking on this. There were instructions once on another site but they are gone now.
The instructions from Rack Doctor say to clean and flush the system before connecting up, and make sure no hose particles are coming loose. If so, replace hoses too. I am going to put in a filter too. Don't know if the one I got will work on the pressure side- it is metal, from Autozone. Has a magnet. No instructions though. On pressure side is better location I think.
To remove rack you need to lower the rear of the engine cradle first, (to the max of the bolts in rear, which are quite long- three or more turns are enough to hold) to allow the rack to get past the engine mount after removing the engine mount bolt (the rack also supports the back of the engine). May need to raise engine some too but don't force it. I used the trans housing and a block of wood. I put jack stands on the front of the cradle which allows the rear to pivot down but still support the car.
Getting the hyd fittings off is a very slow process- a wrench barely fits in there. Use some liquid wrench overnight to loosen them too. I had to do it while rack was loose and raised from the mount to get more clearance. Once these are loose and off, (and fluid drained) then you can remove the rack from the left side. You first need to remove the u-joint from the splined input shaft. Again a slow process to get the bolt out. Then pound with a shaft from below to drive off the u-joint. Fairly easy. Note how it goes on- the flat spot on the shaft for the bolt. I haven't put it back yet- may be difficult.
Also be careful with the rack mounting bolts- they just press in at the top, and if you push them up and out (by side loading the nut- an air wrench would be great here), there is no way to hold them. I had to carefully tighten one again and get it back in- almost did not work. Would have been a royal pain to get out then. I did not remove the bracket near the engine mount supporting the rack/engine to frame- just the horizontal bolt on the rack. The rack will slide out.
Then once the tubes are loose and the u-joint off, you have to lower the rear of the cradle much lower, supporting with a jack, and raise the engine up to where it feels like it stops. Then you can work the rack out by twisting sideways.
That's where I am now. (I set the new rack in place). Need to clean and flush system, install filter. Install lines, u-joint. Also- had to order new bolts for rack- they were severely stretched from the factory, yet extremely tight. (96 850 145k miles) Suprised they did not fail.
The rack was leaking quite a bit of oil and stop leak did not work. I think I broke something once while trying to loosen the tie rod nut- something popped in the rack.
Maybe somebody has an easier way- glad to hear it if so.