In the photo below, which fluid line (A or B) is the return line?

 

Pete, The hard lines are normally the pressure lines, so I'd say that A is the return line.

 

(A) line is the pump suction line. The return is the top hose on the left drawing with the worm-gear clamp on the pipe nipple that goes in the rack body.
The return would come off the rack after the pressure has been used or dumped. It would be whichever soft line goes to the resevoir somewhere above the bottom. The suction line or feed line will be at the bottom of the resevoir directly to the pump. All pressure lines will be hard lines with screw fittings.

When fitting a new return, be sure to check the clearance between hose and pump pulley...often the new hose will be a little long for fitting and ride on the pulley edge, potentially ruining your day tomorrow.
Just trim off one end or the other, whichever makes the fit work.

 

Okay, so if I want to flush the power steering system, I'd disconnect the A line in the bottom right image and rotate the pump while keeping the reservoir full, correct ?

 

No...
The A line is suction to the pump. That line runs to the bottom of the res from what I see.That feeds the pump. If You want to flush, you have to go thru the pump and recover before it gets back to the reservoir, so disconnect the line thats about halfway up on the res, and find a way to catch the oil that comes out of that. The system goes from res to pump to rack to res. You want to intercept the return oil before it gets to the res.

To do it properly, you also have to turn the steering wheels lock to lock because the rack if full of fluid too...and thats where most of the dirty stuff is. This really is more difficult that it seems. Most folks are satisfied with sucking out the reservoir, running the motor and turning the wheels, and sucking it out again. That will get the majority of the old fluid out. I had to do a better job on mine because the moron that installed the rack used trans fluid in my new rack, new pump and new hoses and I was'nt going to stand for anything less than OEM spec for what was basically a new steering system...so I flush every drop out and wasted a gallon of new PS fluid to do it right.. I also use some Lucas PS rack & pinion conditioner to prevent the "morning sickness" that is so common on these.

If you are doing this by hand, have someone to help you either add fresh fluid to the reservoir as it gets used, or to turn the pump. I just rigged a hose to a gallon jug to collect the old and started the motor and poured fresh in the res as it sucked it out...warning ! ! ! it moves fluid REAL fast and this can get REAL messy if you;re not prepared.

 

Thanks, Lee. Reviewing the fluid flow at the reservoir, I can see you are right. It looks to me that if I disconnect the return line C and rotate the pump while keeping the reservoir full of new fluid, I should be able to get a pretty good flush on the system.

My plan is to put a large plastic pan under the disconnected C line, disconnect the 12V power into the distributor and then crank the engine while keeping the reservoir full of new fluid. Is this pretty much what you did to flush your system ?