Brakes, power steering, hydro boost?

I currently own a 1995 M998A1 with the 6.5L engine. Truck runs great but yesterday it started making a horrible noise when ever I applied the breaks, or turned the wheel (sounded like a bad bearing only louder). I read all of the trouble shooting information I could find, and everything pointed to the steering fluid being low. So I ran out and bought some power steering fluid. I opened the hood and went to take off the power steering fluid cap and before I touched it I noticed fluid was bubbling out of the closed cap.

So does anyone have any idea what my next step should be? I am assuming that either the supply or return hose are clogged since the reservoir was overflowing, I am just not sure if I should replace those hoses, bleed the system, and see what happens next, or if the pump is bad and I should just replace it.

• Engine was warm but not running when the reservoir overflowed.
• The belts that do the alternator and power steering were loose and I tightened them after this happened. Now as you apply the break pedal the master cylinder actually rises and the belts become loose again.

Any help is appreciated!

Thank you,

DominicG

Your PS pump went out...rcsk18330 part number

Hoses are not clogged. What you have is air getting into the system and causing the fluid to become aerated and overflow.

Retired war horse, how much for the new pump. Ok to email me if you would rather.

I would try to bleed the system before investing in a new pump. The procedure is very specific and has to be followed exactly. Mine was doing something similar and I was about to replace the pump and figured I was given solid advice here on the bleeding procedure. Worst case and it is the pump, let me know and I will make you a deal on a brand new one I have sitting in my garage.

Good advice, will do
thanks
Dominic

And.....don't put that power steering fluid in the pump...
the manual shows what fluids to use.

I thought dextrone 2 was the spec. I guess I’ll have to read up some more.
thanks
Dominic

Okay did the power steering bleed four times. Now I have no brakes and no steering. This leaves me to the obvious conclusion that I need a new power steering pump.
Is there a civilian option for this pump? I can't seem to find one online.

Thank you,

Dominic G

UPDATE!

New power steering pump installed, but that made no difference. Brakes work but still feel "funny". Power steering works, but there is a horrible "bad bearing" type sound coming from engine compartment when ever I turn the wheels or step on the brake.
Also after the engine heats up and I turn it off, fluid bubbles out of the top of the power steering pump. Not really bubbles, more like foam.
I have tried all of the line bleeding techniques I have found on this forum and elsewhere. Does anyone know where I can find the correct method for doing this in a TM? Either that or instructions from someone that has done it and been successful?

Thank you much,

Dominic G

Post 3 and 5 above. If air is still getting in, you need to bleed or find leak.

Checked for leaks, non found.
Bled the system to many times to count, although I might be doing it wrong?
All new Dextron II synthetic trans fluid installed with new pump.

What else can it be?

Thanks

Dominic

I not so sure about hmmwv hose routing, but a leaking low pressure return line back to the pump can cause air to get sucked in and give you your symptoms. I’ve even seen a cracked hose suck air but not drip leak fluid. Bend and squeeze all the return lines to see if you have any that are cracked. Really just a guess.

This is the procedure that needs to be followed exactly as stated - http://www.hummerknowledgebase.com/susp/ppsp.html

MODEL: HMMWV
SUBJECT: Power Steering Bleed Procedures
DEFICIENCY: The current bleed procedures in TM9-2320-280-20-2, dated Jan 96, Para 8-29, may not expel all air out of the steering system.
COMMENTS: We are aligning our bleeding procedures with those recommended by Saginaw Steering Systems, the steering system vendor. PROCEDURES:
NOTE Before bleeding the steering system inspect to ensure that hoses are not touching vehicle body or other components and all connections are tight.

1. Shut engine off. (TM9-2320-280-10)
2. Turn steering wheel full left.
3. Raise and secure hood.
4. Fill fluid reservoir to �FULL COLD� level. (TM9-2320-280-20) Leave cap off.
5. Raise front wheels off ground. (TM9-2320-280-20)
6. Turn steering wheel left and right holding wheels at steering stops for five seconds at least 40 times. NOTE: Power steering fluid must be free of bubbles and foam. If bubbles or foam are noted, it could be an indication of a loose connection or leaky O-ring.
7. Check fluid. If any bubbles are seen, repeat step 5.
8. Start engine. With engine idling, add power steering fluid, if necessary. (TM9-2320-280-10)
9. Install reservoir cap.
10. With wheels to center, lower front wheels to ground. (TM9-2320-280-20)
11. Keep engine running for two or three minutes. Turn steering wheel left and right. NOTE: If pump is noisy, recheck hoses for possible contact with vehicle body or engine. If no contact is found and noise continues, switch engine off and repressurize system by following steps 12 and/or 13.
12. Remove reservoir cap. Wait for system to cool. Reinstall reservoir cap. Start engine and check pump for noise, if noise is still present continue to step 13. If noise stopped, proceed to step 14.
13. Turn engine off. Remove fluid from reservoir using a suction device. Refill reservoir with clean, cool fluid. Install reservoir cap. Start engine and check pump for noise. If noise is still present, replace power steering pump. (TM9-2320-280-20)
14. Turn engine off. (TM9-2320-280-10)
15. Check power steering level. (TM9-2320-280-10)
16. Lower and secure hood. (TM9-2320-280-10)
17. Operate vehicle and check for proper steering operation. (TM9-2320-280-10)

I have never seen a power steering system that required such a specific process, and I tried a bunch of short cuts that made sense in my head and worked on every other car I have worked on, but nothing worked until I went line by line. This included the silly part of turning the wheel to the left before raising the hood (ok, I know that makes no difference, but rules are rules!). Seriously, there must be some reason for these details, and in my case, they did work.

Make sure you turn the wheels to the left before raising the hood!

I guess I won the lottery when I installed my winch. I just filled the reservoir and turned the wheels right and left a dozen times on the ground running, checked fluid, add a few ounces, and down the road I went.

Sintorian. One question, and it's based on how I read what other people write. I worked for several years as a research review/human use committee chairman and had to read upwards of a dozen research proposals a week. People don't always write exactly what they mean.

Ref:

6.

1. Turn steering wheel left and right holding wheels at steering stops for five seconds at least 40 times. NOTE: Power steering fluid must be free of bubbles and foam. If bubbles or foam are noted, it could be an indication of a loose connection or leaky O-ring.

Does this mean
a. Turn wheel to the left, hold five seconds, then turn right and hold for five seconds, 40 times EACH side (left, then right),

OR

b. Turn wheel left, hold five seconds, then turn right and hold for five seconds, a total of 40 times total left-right pairs, meaning 20 each side.

It is absolutely not clear from how this is written.

Anyone else?

NormB said:

Sintorian. One question, and it's based on how I read what other people write. I worked for several years as a research review/human use committee chairman and had to read upwards of a dozen research proposals a week. People don't always write exactly what they mean.

Ref:

6.

1. Turn steering wheel left and right holding wheels at steering stops for five seconds at least 40 times. NOTE: Power steering fluid must be free of bubbles and foam. If bubbles or foam are noted, it could be an indication of a loose connection or leaky O-ring.

Does this mean
a. Turn wheel to the left, hold five seconds, then turn right and hold for five seconds, 40 times EACH side (left, then right),

OR

b. Turn wheel left, hold five seconds, then turn right and hold for five seconds, a total of 40 times total left-right pairs, meaning 20 each side.

It is absolutely not clear from how this is written.

Anyone else?

Click to expand...

I didn't thin that much into it, but I see what you are saying. I did left for 5 seconds and then right for 5 seconds a total of 40 times which did seem like a lot. Could quite possibly work with half the effort. I did try the same as Juan with it running and on the ground. I wasn't as lucky and ended up with the reservoir over flowing with a frothy mess.

Okay, tried this one time, did 40 left and 40 right, everything looks good. I get up to step 11, turn off the engine and the steering fluid started pouring out of the pump, with the cap on?/!
I am now thinking that the system is somehow sucking in air like Cwajciec was saying. This is driving me nuts HA.
Maybe humvee fairies came and fixed it today while I was at work.
I will keep you all posted.

Thank you,

Dominic G

DominicG said:

Okay, tried this one time, did 40 left and 40 right, everything looks good. I get up to step 11, turn off the engine and the steering fluid started pouring out of the pump, with the cap on?/!
I am now thinking that the system is somehow sucking in air like Cwajciec was saying. This is driving me nuts HA.
Maybe humvee fairies came and fixed it today while I was at work.
I will keep you all posted.

Thank you,

Dominic G

Click to expand...

NAPA sells the high pressure hydraulic hose by the foot. Personally, I would replace both hoses to/from the cooler and the hose from the Cadillac valve to the fitting on the fan shroud that leads to the fan clutch.....and put on new hose clamps while you're at it. Even if that's not the source of air intrusion, it's worth the time and money IMO. BTW, Did you replace the o ring on the PS pump hose when you replaced the pump? This comes from a guy who learned the hard way