I've been doing some other repair work on my 1994 s10 Blazer (4.3L 4WD LT Tahoe). Somehow, I managed to get the belt on in the wrong route, which I think loaded the power steering pump bearing too heavily and caused it to dump most of the fluid out over the past week. I realized this when I filled it back up and it all dumped out over the next 30 mins or so. The blazer was up on a couple ramps in front. Engine was cold, hadn't driven in a couple days. Not drive-able yet either. It is equipped w/ a tanked power steering pump.

Does this mean my only course of action is to remove the PS unit (pump, lines, etc.) and replace it all? As far as I know, it's the original unit.

 

I opted to go ahead and replace the whole pump unit. I had already been replacing several other parts on my blazer, so I wanted this to be the last time in a while I had to tear down this hardware.

I had a hard time finding some good pictures explaining how to do this step-by-step, so I thought I'd at least provide a picture walkthrough of what I did for those like me who have never done this before. Here's how I did mine:

1994 s10 Blazer
4WD, Auto trans
4.3L W
Tahoe LT
~164k miles
Reservoir attached to power steering pump
Afaik, this was the original power steering pump

Tools needed:
- Ratchet/socket sets (will need both US customary + Metric sockets)
- Various ratchet extensions: 3", 6", 12"
- Flashlight
- Penetrating oil (WD40, PB Blaster, etc.)
- Pulley puller tool (I borrowed one like this: Performance Tool W87022 - Pulley Tool | O'Reilly Auto Parts from my local O'Reilly store)
- Anti-seize compound (optional, if you're like me and don't like dealing w/ corroded parts from time to time)
- cable ties (optional, for strapping parts out of my way)
- Torque wrench (I didn't have one so I just winged it, but there probably are torque specs for all these things, should be easy to find w/ a Google search)
- 7/8" hose clamps (in case you need to replace the ones on your low-pressure PS line
- Channel-lock pliers
- New power steering fluid

Beginning:
- Disconnect battery (don't want any surprises!)

- Remove air cleaner box (be careful when you do this: there's a small hose connected to the air filter box that goes to the engine block beside the brake fluid reservoir. Unhook this hose from the filter box before you take the whole thing off. I noticed repeatedly pulling my air cleaner box on and off caused the sensor interface to the engine block to tear. I'm trying to figure out what to do about that now).

- Drain fluid from power steering reservoir. If you've got a remote reservoir, you need only unhook the hose from the pump and raise it over the elevation of the reservoir to keep it from dumping out. Make sure to not let trash or dirt get into the hose if you'll be reusing it. Some manuals say it's best to dump all the fluid and start fresh and/or flush the hose. I had a bad leak and very little oil in mine to begin with, so I went on w/o doing this step.

- Remove upper shroud from radiator/fan. Shroud is two pieces: upper and lower. Only need remove the upper for this replacement.

How to remove upper shroud:
- Unfasten: (3) 10mm screws across the top that hold the upper shroud in place and (2) 10mm screws per side. Look down where the upper and lower radiator hoses interface to the radiator. These things use some tapped metal clips to clamp the plastic shroud together. You may want to use some channel-lock pliers to hold these clips. When I was loosening mine, I broke the plastic on one. I guess it gets brittle over time.

- Finagle shroud out from around fan. I popped the left side loose, then bent the right side slightly to get around the upper radiator hose. Then, I pulled mine out from the right (upper rad. hose side)

- Remove fan

How to remove fan:
Assume: shroud already removed
- With serprentine belt in place: loosen (4) nuts holding fan to water pump shaft. I think they're 13mm. You need to leave the belt in place to resist the loosening torque you apply. After you get the nuts started off, you don't need the belt tight anymore.

- Loosen the serpentine belt. Mine uses a tensioner with a nut sticking out the end. I just grab onto that nut w/ a 5/8" wrench and rotate CCW until I can slip the belt off the alternator (thing to the top right, look for coils of copper wire through the vents if you are unsure what it looks like). You only need to get the belt loose. Don't worry with taking it completely off yet, it'll be easy w/ the fan gone.

- Continue removing all (4) nuts holding fan in place.

- With nuts gone, slide fan assembly off the water pump shaft.

Pictures:
https://i.imgur.com/dnlxYwq.jpg
Here's all the stuff removed so far (left to right): fan, upper shroud, air cleaner box. Note: it's removed in right to left order.

https://i.imgur.com/0fV3RcD.jpg
This is what the front end should look like. I labeled the major components in case you are unfamiliar with them.

https://i.imgur.com/viN4f0Y.jpg
This is what the side view should look like. I labeled the hoses: the HP hose is the thick one w/ the crimped connections. The LP hose is just clamped in place. The other two clamped hoses are oil lines, ignore them.

- Remove power steering pump pulley. This pulley is pressed onto the pump shaft, so you will need a special tool called a pulley puller, pretty much self-explanatory. Here's a pic of what mine looked like installed: https://i.imgur.com/KNKk7TE.jpg?1

https://i.imgur.com/lKa9sdJ.jpg
https://i.imgur.com/4lokqiD.jpg
https://i.imgur.com/erD3vmR.jpg

The pullers often don't have extensive how-to guides in them. When you're pulling the pulley OFF, you want to pull it off by pushing against the shaft. On mine there was a couple of split collars to loop around the **** on the pulley. These rode on a threaded rod that pushed against the pump shaft. The metal ring you see just keeps the split collars from falling off. I used the limited instructions in the puller box to figure out what to do. Shouldn't be too difficult.


- Remove nut from pump mounting bracket, near drivers side. There's a stud coming out of the: exhaust manifold (I think), with an extra nut that holds a bracket connected to the backside of the pump. I shot mine w/ some penetrating oil because it looked completely rusted on. I worried I couldn't get it off.
https://i.imgur.com/bfacbxV.jpg

But I let it sit a couple minutes and it came right off, no problems:
https://i.imgur.com/UsOhVdk.jpg

- Remove (1) screw holding the oil lines (metal) that run under the pump.

- Remove (3) screws holding the power steering pump to the aluminum mounting bracket.

Picture:
https://i.imgur.com/FGz4NGB.jpg
See red highlights. I'm not sure what size these were. The oil line bracket screw is shorter than the other three.

- Remove the lowest mount screw: see the previous picture - where my ratchet is currently. I believe it takes a 9/16" socket. This is 1 of 3 mount-to-engine block screws.

- Remove alternator/engine block mounting screws. The trick was to realize that, at some point, the whole mount that holds the alternator and power steering pump, will have to come off the engine block. Loosen enough to get the pump out. I don't have a picture of this, and your setup may be entirely different. I only had two screws: 1 to a black metal support bar, than a second long screw that held the alternator in place. Optional: later this whole thing will come out and you'll have to make sure the alternator is not hanging by its wires, so it may be better to just take the alternator off completely. I didn't, but I can understand why it'd be a good idea.

- Remove the mount screw BEHIND the reservoir. This is tough to see. When the pump is in place, it's right behind the reservoir, no way to get to it. That's why you have to take the other brackets loose first, to access this screw: https://i.imgur.com/1VO1Pho.jpg I think you'll need a 9/16" socket. This is 2 of 3 mount-to-engine block screws.

- Remove the last (3 of 3) mount-to-engine block screw. This one is hidden inside the casting, below the alternator. Again, should be 9/16" socket. https://i.imgur.com/q9r4CNv.jpg

Now, things get squirrely with the alternator/PSP mount. The whole thing should be able to wiggle around. Maybe not a lot, but the goal is to get it loose enough to get the pump out: https://i.imgur.com/5L8idG8.jpg The main thing is: do NOT let the mount fall such that the alternator wires (look on the back) get pulled on hard. You could cable tie the mount up or something, just don't stress those wires. Don't let it hang by the wires.

- Unhook the LP power steering hose. Disconnect the LP hose clamp and pull the hose off. It'll be tight. I used some channel-lock pliers to break the hose loose, then pulled it off manually. Doesn't matter which clamp you unfasten. I went w/ the one closest to the pump. Save your hose clamp or use a fresh one during reinstall. You will most likely get fluid dripping out now, so be prepared. https://i.imgur.com/3YXD3Ud.jpg?1 See: red circle.

- Remove pump from behind mount. This is it! Finagle that pump out from behind the mount. I just rested the mount on the water pump to protect the alternator wiring. Do whatever you need to get that pump out, but be careful not to pinch or crimp the HP hose, unless you're going to replace it anyway.
https://i.imgur.com/mlZr9rv.jpg
https://i.imgur.com/ArIrWTq.jpg

- With the pump out from behind the mount, use a wrench to disconnect the HP line from the rear of the pump. Make note of the o-ring position on the HP fitting.
https://i.imgur.com/dUcaa6V.jpg

Now, your pump is out! https://i.imgur.com/7fZMDe6.jpg It probably still has some fluid in it, so be prepared for more oil dripping out!

- Remove the mounting bracket, nuts, and studs beneath. These parts did not come with the new remanufactured pump I bought. Make note which stud went in which hole. You can use the HP fitting nut as leverage w/ a 1" wrench if necessary: https://i.imgur.com/f6LM3SM.jpg
https://i.imgur.com/wyoUsDF.jpg

- Go to store. Acquire new pump. Turn old one in for core charge refund.

- Install studs and mounting bracket onto new pump just as removed from old pump.

- Thoroughly clean old HP hose connector and replace o-ring with new one provided with new pump. I almost didn't see this when doing mine. Clean the threads as best you can: an old tooth brush wet with brake cleaner should do it. Stick the new o-ring on the interface and reinstall to the back of the pump.
https://i.imgur.com/9YUzVsQ.jpg

Reinstallation is basically the reverse of all the above. I really only struggled with one thing: getting the oil filter line bracket screw back in place. Note the huge gap here in red: https://i.imgur.com/QwTNTNI.jpg I'm not really sure how that happened, but it gave me a fit putting it back together. I also stripped the worm gear on my old hose clamp, so I replaced that on the LP hose.

- Torque all screws, nuts, etc. during reinstall according to factory specs if you have a torque wrench. I don't have the numbers, but I don't think they're hard to find.

- Refill reservoir and follow instructions for priming pump (these came with the new pump). You have to turn it slightly CW or CCW.

- Follow manual/instructions for bleeding air from the system. These are also an easy search/find online. It's something like: jack up vehicle front. Start vehicle. Steer left and right, maxing out each direction a few times until fluid is not foamy. Foam = air in lines = bad. Then test drive and refill fluid as needed.

I'm still struggling to beat a new starting problem, so I haven't test driven mine yet. Hopefully today!



Now that I'm done w/ the reinstall, I'm pretty sure my whole problem was a bad o-ring on the HP line where it connects at the back of the pump. I found this when installing my new o-ring: https://i.imgur.com/9s7h2RI.jpg I think that o-ring cracked recently.

Good luck fixing yours!