Power Steering Flush Procedure per FSM...

[Rocko973]

Need help...please. The factory service manual (for 2003 Silverado 1500 HD, 6.0L) for flushing the power steering fluid says to "remover the fluid return hose at the power steering pump reservoir... plug the inlet..." But their diagrams show TWO return hoses. So, was it suppose to say unplug the "TWO" return hoses, and plug BOTH inlets to reservoir..."? I actually tried doing just one hose, the higher up one, and when I followed their procedure, the fluid was just trickling out, took forever to fill up a half liter bottle. But before I re-do it with both return hoses, i wanted to run by the experts first...

 

Also, how can I tell which power steering system I have, the Rack and Pinion, or the Recirulating Ball System?

 

And how do I know if I have Hydroboost? Maybe it's just me, but I find that the manual can be very confusing sometimes...

 

Thank you all in advanced!

 

[Chris]

Is your master cylinder bolted directly to the firewall or does it have the black vacuum drum behind it like mine? Drum being the master cylinder is Vacuum brakes, bolted directly to the firewall is hydroboost

 

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[jhm]

I was told by GM Service that they do not reccomend flushing the power sterring fluid. Why are you doing this?

[bossier62guy]

The power brake booster located behind the master cylinder utilizes vacuum to assist w/ braking. The hydro-boost system uses the power steering systems hydraulic power to assist w/ braking. Therefore you would have hydraulic lines attached to it from the power steering pump. As far as the rack & pinion vs the recirculating ball type systems....google them and you'll find some good pictures. But as one poster mentioned.....power steering fluid is something I do not bother with, although some folks do believe in it. The GM service manuals are definitely not written for the novice.

 

Try the dictionary of automotive terms.....pretty good info.

 

http://www.motorera.com/dictionary/INDEX.HTM

[Rocko973]

Is your master cylinder bolted directly to the firewall or does it have the black vacuum drum behind it like mine? Drum being the master cylinder is Vacuum brakes, bolted directly to the firewall is hydroboost

 

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My master cylinder (or P/S Gear) is bolted directly to the firewall, so it appears that I have the hydroboost. Is there an RPO code that correspones to that, that I can find listed in my glove box? Thanks!

[Chris]

RPO JH-my parts truck it was JH6 and it was a 2500HD

[Rocko973]

I was told by GM Service that they do not reccomend flushing the power sterring fluid. Why are you doing this?

 

A lot of you don't bother with the P/S fluid? I find that interesting. Well the reason I am doing it is that my fluid is very dirty, it's never been changed in its 10 years. Wouldn't you want to swap it all out with fresh fluid too? If GM doesn't recommend flushing the P/S, why would they put it in their service manual?

 

What's confusing to me is that GM's procedure for flushing refers to one return hose, and even their Diagnostics and Procedures Diagrams show only one return hose. But in their procedure for removing/replacing the P/S pump shows TWO return hoses, which BTW, matches what I actually have. In fact the procedure here is EXACTLY the same as the one in my service manual for a Corvette, as if they just copied it. I've never seen one with two return hoses, which threw me for a loop. When I removed just the one that connects to the Master Cylinder for draining per their procedure, the fluid was just trickling out. So I was wondering what everyone else does. I can't be the only one who has tried GM's procedure on this type of engine???

 

All my other cars have just one pressure hose and one return hose, and flushing has always been pretty straight forward and problem-free...

[Rocko973]

OK, I think I understand this now, at least better than before. Correct me if I am wrong, but I believe that "other" return line the the manual mentions is actually the Hydroboost hose. So there really is just "one" P/S return line. No wonder it was just trickling out... Hydroboost is new to me, Live and learn...

[Chris]

I think you got it figured out

[CapitalTruck]

The return hose is the rubber hose with a low pressure garden variety clamp. At least on my non hydro boost version. I took that hose off, drained it into a mason jar, and plugged the port on the reservoir. (Where I had just removed the hose). I then filled the reservoir, and turned the wheel full lock (I put the front on Jack stands). I the refilled the reservoir and turned the wheel the other way full lock. I repeated this cycle until the power steering fluid was clean coming out the hose. Then I reassembled. The steering felt LIKE BUTTER after this. Noticeably more awesome. IMPORTANT: This was done with engine off. Don't let reservoir run dry.

[Rocko973]

The return hose is the rubber hose with a low pressure garden variety clamp. At least on my non hydro boost version. I took that hose off, drained it into a mason jar, and plugged the port on the reservoir. (Where I had just removed the hose). I then filled the reservoir, and turned the wheel full lock (I put the front on Jack stands). I the refilled the reservoir and turned the wheel the other way full lock. I repeated this cycle until the power steering fluid was clean coming out the hose. Then I reassembled. The steering felt LIKE BUTTER after this. Noticeably more awesome. IMPORTANT: This was done with engine off. Don't let reservoir run dry.

Very cool... thanks! Interestingly, my GM service manual says to "idle engine while an assistant keeps the reservoir full, then turn off engine, turn steering wheel from lock to lock, then reassemble, then start engine and idle for approximately 15 mins., then repeat if fluid is still dirty." I find these differences in the procedure interesting. Some say "idle" engine, others say keep engine "off". Particularly, my Honda service manual for my Accord (which is a manual) says to start engine and keep turning the wheel lock to lock until nothing but "air" comes out of the return hose, while my GM Silverado manual warns you to NOT let the reservoir run dry. Why so opposite? It's not the fact that my Accord is a manual becaues my Corvette is also a manual and their procedure is the same for the Silverado. Are the power steering systems really that different...or does it not really matter whether the engine is off/on or if we get air in the system?

[CapitalTruck]

This is what worked for me. I would sure be hesitant to do it with the engine on. Too much happening too fast.

[Rocko973]

This is what worked for me. I would sure be hesitant to do it with the engine on. Too much happening too fast.

Yes, I've been thinking about that. When I did my Honda, the fluid came out faster than I can put it in, although their manual doesn't say to keep it full. I was just doing it because I didn't feel comfortable running it dry. But it came out so fast that I had no choice, so I just ended up running it until nothing but air came out, just like the manual says. So far I haven't had any problems with it.

 

So I am worried that the Silverado might run out just as fast as my HOnda and end up getting air in the p/s system, as GM warns against. But that's their procedure that's outlined in their Factory Service Manual. I may have someone start the engine just for a couple seconds so I can see how fast it runs out, and if it's fast, like my Honda, then I'll probably follow your procedure, i.e., with the engine off.