HMMWV Fan Clutch Demons - Please Advise

[General Hood]

I had posted a while back that my Cadillac valve was not functioning so I bought a NOS replacement from a fellow SS member. Once replaced and system bled, upon start up the fan clutch blew PS fluid everywhere. I replaced the fan clutch, bled the system and again another fan clutch sprays PS fluid. This time, at the advise of others, I replaced the PS pump with a NOS unit along with yet another NOS fan clutch. After bleeding the system, and immediately upon start up, the fan clutch blows PS fluid. Something is wrong, the problem seems to have started with the NOS Cadillac valve replacement and has been a costly dilemma since. I may be missing something simple, but all the plumbing is hooked up correctly, and I followed this procedure of bleeding the system


1. Ensure
engine is shut off (TM 9-2320-387-10) and turn wheels all the way to the
left.
2. Add power steering fluid
(TM 9-2320-387-10) to FULL COLD level on reservoir. Leave reservoir cap off.
3. Raise front wheels off ground
(para. 8-2). 4. Turn steering
wheel left and right, holding wheels at steering stops for five seconds, for at
least 40 times.


2.
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. • Fluid with air in it will have a
milky appearance. Air must be eliminated from system
before normal steering action can be obtained. 5.
Check power steering fluid level (TM 9-2320-387-10). If
any bubbles are seen, repeat step 4. 6. Start engine (TM 9-2320-387-10) and with engine idling, add
power steering fluid (TM 9-2320-387-10) if
necessary. Install reservoir cap. 7. Turn wheels to center, shut off engine, and lower front wheels to
ground (para. 8-2). 8. Start
engine (TM 9-2320-387-10) and run engine for two or three minutes, turning
wheels left and right.

 

[charlietango]

You’ve ruled out the QD fittings for sure? I read about and have had QD’s go bad on hydraulics before. Seems like a strange situation


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[Bighorn]

So your power steering pump is foaming over and the fan is blowing the power steering fluid around?
I dont see what the fan clutch has to do with anything.
It is supposed to be tight when its cold, will loosen up after about 5 minutes, and then only stiffen up when the engine is hot once up to normal op temp.
You are sucking air into your power steering system or something wrong inside.
Check all fittings in particular the LOW pressure return lines to the ps pump.

 

[Retiredwarhorses]

I would post pics of how you have your pump plumbed from the pump to the Hydro booster and Cadillac valve.

 

[General Hood]

So your power steering pump is foaming over and the fan is blowing the power steering fluid around?
I dont see what the fan clutch has to do with anything.
It is supposed to be tight when its cold, will loosen up after about 5 minutes, and then only stiffen up when the engine is hot once up to normal op temp.
You are sucking air into your power steering system or something wrong inside.
Check all fittings in particular the LOW pressure return lines to the ps pump.

Negative! No foaming over, no milky looking PS fluid. The fluid is blowing out of the fan clutch

 

[General Hood]

I would post pics of how you have your pump plumbed from the pump to the Hydro booster and Cadillac valve.

 

[Bighorn]

Negative! No foaming over, no milky looking PS fluid. The fluid is blowing out of the fan clutch

Apologies.
Well that is a cluster.
Glad my M1009 doesn't have all that junk just to spin the fan.

 

[Retiredwarhorses]

Are the 2 hoses from the pump coming off the correct ports? The cooler and fan are correct in there routing

 

[Retiredwarhorses]

Hydrobooster to passenger side, drivers side too Cadillac valve

 

[General Hood]

Are the 2 hoses from the pump coming off the correct ports? The cooler and fan are correct in there routing

Yes, same ports they were removed from.

 

[General Hood]

Arrow points to where the PS fluid blows out, behind dust cover

 

[Retiredwarhorses]

Yes, same ports they were removed from.

sorry, you need to verify they are correct, not assume....regardless of where they came off, it's just a visual.

 

[General Hood]

sorry, you need to verify they are correct, not assume....regardless of where they came off, it's just a visual.

Confirmed visually

 

[Retiredwarhorses]

The only thing that keeps the fluid in there is a large o-ring. You can plug off the fan outlet with a brass fitting and bleed the system, it doesn't know there isn't a fan clutch installed.
but if you have a serous over pressure, you will only find this with a PS tester...either buy one on eBay or take it to a shop that has one. The test procedure is in the TM

 

[Retiredwarhorses]

While I've had leaky clutches, it's always been solved with an NOS fan clutch

 

[General Hood]

While I've had leaky clutches, it's always been solved with an NOS fan clutch

I will look into the pressure tester. I don't want to end up with a garage full of formerly NOS fan clutches trying to overcome this obstacle

 

[charlietango]

I’ll share this just because, - I had a hydroboost fail on my 97 dodge 1ton that caused other issues. Brakes worked but it caused the steering system to fail. I threw power steering pump at the wrong problem and wasted a lot of time and money. I gave up and let a shop test it all and when they finished I wish I had just taken it to them in the first place - but I did learn something so there’s that


Good luck, and keep us posted

 

[General Hood]

While contemplating my next course of action, I disassembled the original fan clutch expecting to see a bad o ring or ???? But the 2 o rings on the spindle and one o ring in the dust cup look to be okay. Nothing to implicate why a deluge of power steering fluid would blow by

 

[General Hood]

Today, I plugged the line from the Cadillac valve to the fan clutch. Performed the TM method of bleeding the system ( just to confirm no air in the lines) Cranked it up and immediately a rupture occurred in the line from the Cadillac valve to the cooler. PS fluid sprayed from here to kingdom come. I'm inclined to believe there is definitely a pressure issue here, but the cause eludes me. Can a faulty NOS Cadillac valve be the culprit?

 

[ken]

I know GM PS pumps have a pressure relief valve inside. It just dumps back into the tank. It is for when the steering wheel is at a full lock I didn't see where you changed the pump. If you did, I missed it. If you did there is a good chance it was a bad rebuild. My luck lately has been poor quality from the auto part industry. Mabye your pump is not relieving? I would install a hyd pressure gauge from northern equipment on a line from the pump. At least to narrow down the culprit.