First off, pardon the cruddy pics - I was doing this in the middle of a shop floor, with poor fluorescent lighting on one side and sunlight at my back. Santa Clara is fitting LED tubes in place of fluorescents as a treat from the city but we got a ways to go before the lowest bidder gets to us
Now, I'm doing this with the powertrain removed from the vehicle - you probably aren't, so I'll make suggestions as I can. However, working with what you have is, well, exactly that - on you. First thing you want to do is unbolt the pump from the engine and let it drop.
The P/S pump has two lines going to it: the suction hose, and the pressure line. Stick a drain pan underneath the car to catch all the nasty old P/S fluid that'll gush:
Grab your needlenose pliers and release the three-finger ("shocker" wahaha) clamp that holds the suction line to the pump, then twist to break the grip and pull it off the pump:
Let it drip out; this will empty the reservoir as well. Next, unbolt the banjo bolt fitting that holds the pressure line to the pump. WARNING: make sure to first remove the harness connector from the pressure switch, otherwise you may rip it off when you try to remove the pump. If you have a gen3, you have an idle-up switch instead which will have two vacuum lines going to the intake manifold; both systems serve the same purpose, to raise the engine's idle when power steering is under high load (i.e, at steering lock) to prevent the engine stalling. I got it easy, using a 24mm socket and impact wrench:
...otherwise, you can try holding the pump with a pair of lineman's pliers:
...while you use an adjustable wrench or a ratchet and 24mm socket (if you can get it in there).
The pressure switch is screwed into the banjo fitting, no need to remove it:
Remove the double-gasket from the pressure line banjo:
Now, with the pump out of the car, you can spin the pulley by hand to pump out most of the fluid remaining in the unit:
Stick the pump in your vise and counterhold the pulley for removal. You can use a cam pulley holder, a long extension, some pliers, or a spare wrench like I did:
If you have an impact driver or wrench, easy peasy with a 17mm socket. Otherwise, break it loose by hand and back it off some so there's a gap:
Take the pump out of the vise, grab a rag and hold the pulley. Have the pump in midair:
...then, see that bigass mallet next to it? Well, grab yours and whack the nut until the pulley is free from the splines on the shaft. Rust is the usual culprit here. Unscrew the nut, and remove the pulley:
...oh man, those pumps are gross! If that wasn't enough for you, here's a closer look:
Now we remove the brackets. Again, this guide is for a 5S pump; the only difference for a 1MZ pump is the brackets. There's three 14mm bolts on the back to deal with, 2 longer ones and a shorter one:
The 2 longer ones hold the front bracket to the assembly, remove them and the front bracket first:
Remove the final bolt, here are the free brackets:
At this point, clean up the pump and brackets. I used a heated parts washer, but use whatever makes you happy. Don't worry about getting solvent or soap into the pump, we'll be washing the guts with brake parts cleaner.
Now, unbolt the suction port union (12mm bolt):
Twist it out, there's an o-ring:
Next, unbolt the pressure port union. Stick the pump back in the vise; this'll be more difficult now that the brackets are off. Try to clamp on one half of the housing or the other, but if you must squeeze both housing halves together, don't squeeze too hard. An impact wrench and 24mm socket will make this cake:
The union has an o-ring as well:
Underneath it lies the flow control valve and spring. Here's a top-down view of the valve:
...flip the pump over and dump the valve and spring out onto your work surface:
...if they're not coming out, pour some ATF into the hole and work the valve up and down with your finger to lube it up (wahaha). Next up, undo the 4 12mm bolts that clamp the rear housing:
...impact driver, if you have it. There are 2 short bolts and 2 long bolts; the way to remember where they go is to look at the height of the boss on the pump. The short bolts will have a short boss:
...and the long bolts will have a tall boss:
...after removing the bolts, the housing will pop up because it's holding down a wave washer. It has a projection inside with an o-ring around it:
...remove that and discard. Here's what's on the other side:
...notice the wave washer and the o-ring just below it:
Remove the wave washer and set it aside (we're going to use it again). Remove the big o-ring and discard.
Next up, pull the side plate that covers the end of the pump stack off:
And here's the heart of the pump:
...the shaft spins the rotor, and that flings the vanes out in the cavity and seals them against the cam ring (outside part). The eccentric shape is to boost static pressure, IIRC.
Remove the housing gasket:
There's a snap ring on the shaft holding it against the rotor to prevent the shaft from backing out of the pump:
Use a small, pocket flathead to remove the snap ring and discard it:
Then, flip the pump over onto your work surface to drop the cam ring, rotor, and vanes out:
...something to note. What you're seeing in that image is the stack upside down. The marks on the cam ring would be facing outward (they're facing down now), but the mark on the rotor is facing backward (up in the pic). The FSM says to assemble them with both marks facing outward. Notable is that all 3 pumps that I rebuilt have the marks as you see in the pic, not as the FSM says. We'll revisit this.
And now, we can remove the shaft:
Put the pump back in the vise, grab your electrical tape-wrapped flathead and pry out the shaft seal:
...these pumps are a very simple design; there isn't a "skateboard" bearing like other pumps. Rather, there's a long bearing and the shaft rides on a film of ATF in it. Check out the cool lube channels in the bearing:
...and that is disassembly. Go ahead and clean both housing halves and all the other parts with brake parts cleaner to prep for reassembly. Here's the rebuild kit:
Open it up, nab the new shaft seal and lube it up good with ATF (Use ATF whenever you're lubing stuff up on this job), inside and out. In fact, just dip it in ATF if you want! Put the front housing back in the vise. A 27mm socket is perfect for installing the new seal:
...grab your dead-blow mallet and tap it in until the seal is flush with the housing. The 27mm socket is slightly larger than the seal, so it will stop at the housing. Flush:
Now back to the shaft. When shaft seals get old and aren't doing their job anymore, sometimes they wear grooves in the shaft:
The new shaft seal should seal fine against the shaft. If your shaft is visibly tapered (wahaha), you got a problem; get a replacement pump. Lube up the shaft (wahaha) and slide it in until it stops:
Lube up the cam ring and install it to the front housing:
...only two of the holes are big enough to accommodate the straight pins. Note that the three dot-marks are facing outward.
Lube up the rotor and install it to the splines on the end of the shaft:
...you may have to hold the shaft from the other side to prevent it backing out. Note that I followed the FSM instructions and faced the square-mark outward. We'll see if there are any adverse reactions!
Next up is the vanes. Take a look at this one:
...note that one side is square and the other is rounded (if you can't see, the left side is rounded). The square side faces toward the shaft, and the rounded side seals against the cam ring when the vane gets flung out. I want to point out that the pump from the donor car (PO was running Idemitsu P/S fluid) had vanes that were significantly more worn than the pump out of my car (running MaxLife ATF). If the vanes are worn on both sides to where you can't tell which side is out or in, check the discoloration.
Lube up the vanes with ATF, and slip them into the slots on the rotor. Don't force them or you may chip the rotor or vanes, which will cause cavitation issues. Here're all the vanes installed:
Next up, install the housing gasket. All the ATF you've been lubing the installed parts with will have leaked onto the flat sealing surface of the front housing. Wipe that up first, then put the housing gasket on. There's a wrong way:
...notice how it covers the hole at the bottom of the pic. And the right way: