Do a google search... there's a very detailed post with pictures ...this has been well documented: The H3 pump when the pump is disassembled and parts are laid out and shown side by side with the others, the H3 pump is more H/D inside than the others and produces more flow/pressure. Others who have installed a Colorado pump had too little assist. And even less with an SUV pump. Just do a google search and you'll probably find what I'm talking about. If your rig has small tires, maybe you could get away with a Colorado pump??? But in summary, they're each different internally.
More than likely all you REALLY need to do is remove the PS pump/unit and clean out the filter. The filter generally clogs and starves the pump of fluid. It may growl. You can't see it, but there's a thick cottony filter that's molded inside the reservoir. There's a well-known post where a guy tried a few rebuilt pumps with no success, and finally at wits end, he cut the reservoir in half with a bandsaw which revealed the filter. This was back when reservoirs were still available. A lot of guys have successfully removed the reservoir (very gingerly!!! don't break the return nipple!!) and backflushed it, and then the PS usually works again.
As a matter of fact I just did mine today. My PS has been weak, real weak for a while and I put it off. My tk's pump wasn't grinding. I exchanged the fluid a couple yrs ago. I wonder if the new GM fluid dislodged particles which caused the filter to clog? IDK. My rig has 208k miles...everything is original on the P/S. The procedure is: I removed the air box, then removed the pulley and then the pump. CAUTION: If you break the return hose nipple....yer screwed! Treat it like it's the Hope diamond because it's almost as valuable! I recommend to heat the hose on the nipple with a hair dryer to make it supple, then rotate it gently as you gently remove it. Use one of
THESE tools to cleanly remove the clamp straight. A pliers you might twist at an angle and break it. That tool is usefull as heck on any modern car, so it's not a waste of money. And don't drop the pump/reservoir.
I just put clean gasoline inside the reservoir and shook the he// out of it like making a cocktail. Drained and repeated several times. I *Probably* should have removed the reservoir from the pump, but I was low on time and figured if this did the trick it would be good enough for a while. To separate the reservoir from the pump, there are two sliding metal clips with a locking 'tang'. A guy can drill a hole in the tang, stick a screwdriver in them...or a steel rod, and bend those tangs back 'up' ...so you can tap off the clips. Then remove the reservoir. Use a suction gun and some kind of adapter to force a solvent or gasoline back through (backflush) the outlet of the reservoir (where it meets the pump). That's the best approach. Then let the unit and pump sit until the solvent evaporates out and reassemble. When I put my pump back on, I put PS fluid in it and rotated the pulley many times both ways to work fluid back through the pump ...because for sure gasoline probably got in mine. Then I raised the front end of the vehicle on a jack, and "Slooowly" rotated the steering wheel from side to side to pre-bleed the pump, before I started the vehicle. If you rotate the wheel too fast fluid will blow out the reservoir (even with the cap on)...so go slow. This pre-bleeds the system...safer than starting the pump 'dry'. Then, after all that, I started the vehicle and rotated the wheels (front end jacked up) side to side. At that point there was only a little minor bleeding needed.
Anyway, using the flush 'shaker' method seems like I got 90 or 95% of the power steering back ...with 285/R16 tires. That seems good enough right now. I'm going to leave it for now and see how it goes. I probably should have put brand new fluid back in or re-exchanged the fluid.
The way I exchanged the fluid last time was removed and plugged the lower nipple (let the old fluid drain out first), and attach a clear hose from the return hose to a small bucket. Then I filled the reservoir with new GM fluid, and had my wife start the vehicle. Then start pouring new fluid into the reservoir as fast as you can while the pump pushes old fluid into your bucket. You may have to stop briefly to fill the reservoir, b/c you can't get new fluid in as fast as it pumps into the bucket. It only takes a minute doing it that way. You can also move the steering wheel to one side (engine off) which will force fluid into the bucket, and then to the opposite side. Maybe a combination of doing both is the best.
Best of luck!
www.autozone.com
. I'm waiting on a company called h3 altitudes that is supposed to be coming out with a 6" lift to see if I want to go that direction.
