Power Steering woes M1123

[Thunderbirds]

Hey all,

We've been having some dreaded power steering woes, slowly building up to PS failure yesterday and some maintenance not helping thus far.

Hardware:
1999 M1123, single pump/reservoir, serpentine belt.
Dex III fluid level perfect at all times, fresh fluid (6 months).
Cooling fan came on when temperature was reached, and disengaged after, no problems.

Symptoms:
Some slight hissing when revving between 1,000 to 1,500 rpm in the past few months. No other issues.

A week ago, PS was weak at idle, needing some more revs to feel solid at a stand still. Was a little stunned.

Still a solid driver. Yesterday, while pulling into a fast food joint suddenly PS failure unless I revved to 2,000rpm.

Thankfully a 12 mile straight shot from that place via country road doing 55mph, no issues since we were constantly at higher rpm.

Checked everything visually and found a very poor looking return line at the pump/reservoir.





Maintenance done in the past days:

Replaced low pressure hose, replaced Cadillac valve with a know working one with bleed screw at valve (may have been a mistake). Filled reservoir, manually filled hoses with Dex III before connecting them to the Cadillac valve, manually filled clutch hose

Bleed according to TM, up on jacks, engine off, at least 40 - 50 times left, wait 4 seconds, turn right to end wait 4 seconds.

Left in garage overnight, repeated bleeding again this morning.

Nothing really changed, except when I step on brakes, steering becomes harder, when I hit the end (left or right the fan starts spinning up) but still no PS unless I revv to 1,500.

Oh, and now I don't have a temperature indication on the gauge cluster, other gauges work fine.

What have I done, where should I start looking? I do not have any pressure gauges I could use or know how to anyway. Thought about to drive it for some miles, but with the Sturgis motorcycle rally going on this week, I'd rather not endanger the general population.

Thanks for taking time to read and shoot any opinion or question.

 

[Thunderbirds]

Hey all,

We've been having some dreaded power steering woes, slowly building up to PS failure yesterday and some maintenance not helping thus far.

Hardware:
1999 M1123, single pump/reservoir, serpentine belt.
Dex III fluid level perfect at all times, fresh fluid (6 months).
Cooling fan came on when temperature was reached, and disengaged after, no problems.

Symptoms:
Some slight hissing when revving between 1,000 to 1,500 rpm in the past few months. No other issues.

A week ago, PS was weak at idle, needing some more revs to feel solid at a stand still. Was a little stunned.

Still a solid driver. Yesterday, while pulling into a fast food joint suddenly PS failure unless I revved to 2,000rpm.

Thankfully a 12 mile straight shot from that place via country road doing 55mph, no issues since we were constantly at higher rpm.

Checked everything visually and found a very poor looking return line at the pump/reservoir.

View attachment 951631

View attachment 951632

Maintenance done in the past days:

Replaced low pressure hose, replaced Cadillac valve with a know working one with bleed screw at valve (may have been a mistake). Filled reservoir, manually filled hoses with Dex III before connecting them to the Cadillac valve, manually filled clutch hose

Bleed according to TM, up on jacks, engine off, at least 40 - 50 times left, wait 4 seconds, turn right to end wait 4 seconds.

Left in garage overnight, repeated bleeding again this morning.

Nothing really changed, except when I step on brakes, steering becomes harder, when I hit the end (left or right the fan starts spinning up) but still no PS unless I revv to 1,500.

Oh, and now I don't have a temperature indication on the gauge cluster, other gauges work fine.

What have I done, where should I start looking? I do not have any pressure gauges I could use or know how to anyway. Thought about to drive it for some miles, but with the Sturgis motorcycle rally going on this week, I'd rather not endanger the general population.

Thanks for taking time to read and shoot any opinion or question.

UPDATE:

at least fixed the temperature indication. I inadvertently pulled the lead from the temp sending unit right next to the low pressure hose near the back of the pump.

Also, now noticing a low level chirp when at idle, never hear that before. Definitely pulley, belt related, but sounds like mechanical chirp not from the belt itself...

EDIT: To add a pic of the sending unit connector:

 

[Thunderbirds]

Bled the system one more time this morning, did not help.

I have noticed there is just not enough boost/power to go around for brakes AND steering at idle. It gets better at higher rpm.

Now I am trying to figure out is it more likely some o-rings in the power steering pump or hoses, the pump itself, or even hydro-booster getting weaker?

Any opinions are welcome. Are there specific troubleshooting steps not in the TMs I could perform to narrow it down? I don't want to shotgun parts as that almost always is a waste of time and resources.

 

[Thunderbirds]

So, at this point I have replaced my power steering pump, and the three EDIT: four low pressure hoses, as well as 2 of the 5 O-rings on the high pressure side.

I have bled the system over 3 days, mornings and evenings 40-50 turns for a total of 6 or 7 sets, hold for 5 seconds at each stop. Kept fluid level at proper amount.

It worked great after that, but developed a whine after 40 miles then the new pump went out. Completely dead to the point where is no steering AND no brakes present... Trying to find out what happened.

Can anyone confirm that the low pressure hoses connected to the single pump/reservoir are as in the picture? Mainly if I had the Cadillac valve and booster hoses swapped? I read on this forum that could be a problem.

Thanks in advance.

 

[Thunderbirds]

Seems like I have it figured out. (knocking on wood) Would like to document the journey for others out there in the future who experience the same, may help someone out.

Like in the first few posts before, symptoms were steering loss at idle. Replaced pump, started to get moaning and whining about 30-40 miles into new pump, then total steering AND brake loss. Had to trailer the truck home. Put the old, weak pump back in for troubleshooting. While bleeding, I just could not get rid of the air showing up in the reservoir. Previously replaced all low pressure lines and 4 of the 5 o-rings on the high pressure lines. Still too much air for being residual.

So I replaced the two high pressure hoses and o-rings from Kascar. Still too much air. Then, I ordered the hose tube on the steering gear to the low pressure return hose, as I pulled it, there wasn't an o-ring installed at all! (The 5th o-ring that I did not replace previously). The mechanic that installed the elbow used teflon tape around the threads, and that must have failed over time and air was leaking in through that connection, with no o-ring to prevent it sucking air. In addition to that, the tube was also bent. See picture below.

Item 8, Page 178-1, NSN 4710-01-209-4628, TM9-2320-280-24P



Kept bleeding and the air was getting much less. Time to rebuild the pump. Got a reman from NAPA for $83 and a refundable core charge of $24, replaced the innards, reinstalled the original pressure/flow control valve, bled a few hundred rounds. But right now it's back to 99% steering at any engine rpm... Just as advertised.



Not sure if the constant flow of air in the lines ruined the original or the first replacement pump, or just lesser quality pump.

Lesson learned: if you forego looking at even just one item in the system, chances are that is the problem LOL

EDIT:

AND YES, the two return lines ARE important to hook up correctly. The pressure hose and Hydro booster return hose connections are the two closer ones. The Cadillac valve is the single port. Don't ask how I found out...

 

[Mogman]

Any time I see Teflon tape I always worry, that is for water pipe, any hydraulic system that actually needs thread sealer should get a thread sealer not tape.
And as you found out nowhere on a steering system should Teflon tape be found.
Teflon tape can wreak havoc on a hydraulic system as it can cause valves to stick, both the manually controlled type and automatic valves like pressure control and relief valves.
I just bought a lot of used welding stuff from a local high school and all the oxy/acetylene hose connections were loaded with Teflon tape when they all are sealed with a type of flair fitting, what are they teaching those kids???

 

[Thunderbirds]

Well,


the new pump works as advertised, I am so happy things are back operational now.

To help anyone out in the future, I can only HIGHLY recommend getting a power steering analyzer like this one off of Epay,



I paid $78 delivered, and it WILL tell you if it is the pump, the steering gear or the Hydro booster with a HIGH likelihood, if used correctly with the troubleshooting steps in the AM General Testing and troubleshooting guide.



I am so happy with the addition of this tool, well worth the money to find out which of the three components are at fault, or even if it seems like blockage in the lines... Do yourself a favor and get the analyzer for your sanity alone if you have steering issues.