Yes, the low pressure line is the return line. You will want a filter with low back pressure, maybe something that says "full-flow."

Thanks, it was recommended to me that I flush the system out before installing the new pump too so I'll do that as well.

Doesn't seem to difficult, just put the return line in a bucket and turn the wheel a few times. Only tricky part is maintaining the level with the pump on the backside of the engine.

Any idea how many turns it should take to clear the system out and get clean fluid? I'm going to be the guy who will be both adding fluid and checking the condition of the old while someone else turns the wheel so a ballpark idea would help.
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Wouldn't you know, as soon as I think about replacing the pump it performs so well on the way home during lunch break, and on the way back. Turned the wheel once I parked in my spot and it growled and vibrated slightly. Don't guess that'* normal so the replacement is still on.

Quick question, just how much should these pumps whine? I've heard there is some inherent PS pump whine in the 3800 but I don't have much to compare it to. I remember when I first got the car it had zero whine, they told me the PS pump was bad, slapped a new one on, and it whined like it was dying.
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I think it is a characteristic of the quality of the pump. I had a pump that whined loudly on a Caravan but performed fine for seven years. I was told many times that the pump was "going out" and needed to be replaced. I never did replace it. The pump on my '95 SLE doesn't make any noise. (Knock wood!)

Good to know, thanks. I won't be able to install the pump today (waiting on very knowledgeable help!) but it will come soon.

I bought supplies though:

2 bottles of Lucas Power Steering Stop Leak (in case I want to do a fluid exchange in the reservoir down the road)
A Flare nut wrench set, couldn't remember whether it was SAE or metric so I got SAE...hope I was right
A Cardone inline power steering filter
Some worm type screw clamps (I don't trust those standard clamps that require pliers to remove, nor do I like them)
A new power steering reservoir cap (old one didn't quite fit well on the new pump for some reason...it sealed ok but not as well as on the old pump).

And a completely unrelated item...some silicone spray lubricant for the windows in both cars. Really smoothed my truck'* manual windows up great, and I'm sure it'll extend the life of my Buick'* window motors.

Anything else I'll need, besides the pump? I have about a gallon of PS fluid to flush and refill the system with.

Anyway, I gotta go back and arrange a day to do this with the guy, could happen Friday afternoon or this weekend maybe.
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Just as an experiment, I drained the reservoir again and put in enough Lucas Power Steering Stop Leak to fill it up again. Interesting viscosity that stuff has. I did notice some initial decrease in noise and fluctuation so me and a friend set out to test it. I set about irritating the hell out of it by making a turn at every possible intersection instead of going straight. My friend bet it wouldn't last 10 miles, I had faith in the Lucas stuff and said it would. I won, it lasted 11.

It was REALLY irritated by then too. I haven't felt so many vibrations and heard so much noise from it in a while. I think I may have even felt it vibrating slightly while going straight.

That pretty much put the nail in the coffin for this pump.
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Alright, new pump is in. We flushed it, put in the filter, and bled it properly.

My mechanic friend recommended that I drive it for the first few trips (short) with the fluid level pretty high to accomodate any remaining air. I did, then drained it down myself halfway, drove it for another short trip or two, and then brought it to just over the full cold mark.

Results seem promising. I felt some initial variations in assist like I did with the old pump but unlike the old pump, those went away after the first drive. The fluid is clean, and clearish (somewhat red because of the Lucas stuff) and not milky. The last fluid I had in had a light tan color with a milky haze. I think it was due to the bad pump.

Overall, turns feel very solid and consistent. Only a few times did the wheel feel like it was moving without me, and I feel that was due more to variations in pavement rather than fluctuating assist.

This pump is a whiner. It'* not as bad as the last one but it does have a slightly audible whine at low speeds (with the windows down) and a slightly more audible one during left turns. I haven't felt any vibrations at all until just today when I left the driveway...the engine was warm, I had it stopped in the road and turned the wheel to the left. Felt a slight (much less pronounced than before) vibration accompanied with a quiet noise from the pump. Not bad at all but enough to get me thinking. My truck has done it once in the same spot (and I KNOW it'* okay) plus it didn't repeat when I did a low speed left turn manuever in the parking lot here at work so I think it'* alright.

Time will tell, I took it for a fairly long (~50 mile) cruise around town last night with a lot of turns and it did fine. That one minor vibration aside it seems to be doing great. I'm crossing my fingers here, I'm tired of looking at that pump.
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Good luck. Hope you have it fixed for good.

Thanks, but I'm not so sure anymore. :?

Today coming home from work, it started doing it again. Lightly at first but by the time I got home it was pretty bad. I don't think it was as bad as last time but it'* hard to remember.

Got out, checked the fluid. Engine was really hot and the level was hard to see so all I managed to accomplish other than burning myself was gathering that the level was somewhere in between full hot and a bit below it. I am understandably quite a bit frustrated at this point. I'm going to wait a bit until the engine cools off and check the level again. But I don't think I'm going to like what I'll find.

Oddly, I did notice that each time I lowered the level in the reservoir closer to the indicated full level on the dipstick it was accompanied by an increase in whining. I lowered it down to a bit above full cold last night when the engine was quite cold. My problems didn't start again until just this afternoon.

Is it possible that this pump for some reason operates better on a higher fluid level than indicated on the dipstick?
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As long as the fluid does not overflow when everything is good and hot, I can't think how it would hurt to raise the level a bit if it makes things work better.

Gee, I can't remember anyone having so much trouble with a PS pump. :?