HMMWV Fan Clutch Demons - Please Advise

[Retiredwarhorses]

Hmmwv ps testers are on eBay for cheap....the ones for sale are specifically for the hmmwv steering system.

 

[General Hood]

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.

Yes I changed out the pump with a NOS unit, but the problem persisted prior to the pump swap. I was hoping the new pump would have fixed the problem, but no

 

[NormB]

Yes I changed out the pump with a NOS unit, but the problem persisted prior to the pump swap. I was hoping the new pump would have fixed the problem, but no

So, what ever came of this? I just changed out my solenoid/cadillac valve and MAN is it comforting to hear that fan kick in when I unplug the connector.

Had me worried a bit.

You sort this out?

 

[General Hood]

So, what ever came of this? I just changed out my solenoid/cadillac valve and MAN is it comforting to hear that fan kick in when I unplug the connector.

Had me worried a bit.

You sort this out?

After replacing most everything in the system ( lines, cooler, Cadillac valve, temp sensor, time delay module, PS pump, fan clutch 3 times , it ended up being Cadillac valve. The second NOS unit fixed my problem . I have a good sized area in and around my driveway grass will probably never grow again because of the power steering fluid dispersing like Old Faithful geyser, but the truck operates as intended now. I can look back on the ordeal and laugh now, but at the time of frustrating lack of positive results, I do admit to a bit of teeth gnashing

 

[ken]

I feel your pain. My truck came really close to getting a thermal fan clutch and a 6 blade 20 inch fan. I even got a extra water pump pulley and chucked it in my lathe. Then machined the boss off and made a pin to center the thermal fan clutch. When something else fails it's going on.

 

[NormB]

After replacing most everything in the system ( lines, cooler, Cadillac valve, temp sensor, time delay module, PS pump, fan clutch 3 times , it ended up being Cadillac valve. The second NOS unit fixed my problem . I have a good sized area in and around my driveway grass will probably never grow again because of the power steering fluid dispersing like Old Faithful geyser, but the truck operates as intended now. I can look back on the ordeal and laugh now, but at the time of frustrating lack of positive results, I do admit to a bit of teeth gnashing

Wow.

And wow again.

Anaerobic soil bacteria will feast on the mineral oil in the ATF.

https://digitalcommons.unl.edu/cgi/...httpsredir=1&article=1007&context=bioscimicro
Eventually.

Growing up in Florida, pre-EPA, we’d use old motor oil to kill grass, weeds, oleander at the base of our hurricane fencing. Stuff would grow back between oil changes. It’s why, despite bizillions of gallons of oil “seeps” in the Gulf of Mexico, no one ever sees natural oil slicks/spills.

So all the fan clutches, PS pump, TDM and other stuff is spares now?

 

[juanprado]

The General is a product of the BSA. Still lives by "Be Prepared!"

 

[gem1410]

General Hood--did you remove the radiator stack to remove the fan clutch --my clutch is also leaking at the o rings

 

[General Hood]

General Hood--did you remove the radiator stack to remove the fan clutch --my clutch is also leaking at the o rings

Yes, didn't see any other way. I labeled or color coded everything I removed, which helped when putting it back together. If any of your cooler hoses show signs of cracking or age, it would be a good time to replace. At the advice of Infidelgotme, I double clamped all the cooler hoses when putting it back together. Follow the timely bleeding procedure in the TM- no short cuts

 

[GixxerSixxer]

General Hood--did you remove the radiator stack to remove the fan clutch --my clutch is also leaking at the o rings

The cooling stack will have to come off. I couldn't undo the trans cooler lines without pulling the side shielding off. Someone with a lot more tools than me could probably leave them on but removing the side shield on the driver side was necessary. I could have done the passenger with it on but it comes off so quick I figure it was more time efficient to pull it.

 

[BenDeez]

I'm having a similar issue right now, PS fluid blowing out at the fan clutch where the O ring is. I recently did the 6.2- 6.5 swap, I replaced the TDM and the cadillac valve. After testing I'm getting 130-140 pressure going to the fan clutch. For you it was just a bad cadillac valve? Is that what you suggest I try? Is that what should lower the pressure to around 90 to lock/unlock the fan clutch?

 

[Action]

Why did you replace the TDM and caddy valve?

 

[BenDeez]

Fan was constantly running, from other posts I saw those two were the primary reasons why this would happen.

 

[BenDeez]

I'm still having this issue of blowing hoses off. I have too much pressure. I cannot find anywhere in the TM's a diagram of the power steering hoses that include both the power steering fluid reservoir AND the cadillac valve. Everything was plumbed back the way it was but I want to confirm it with a diagram that I cannot find. The engines a pullout ECV 6.5 turbo. Any help appreciated,

 

[General Hood]

I'm still having this issue of blowing hoses off. I have too much pressure. I cannot find anywhere in the TM's a diagram of the power steering hoses that include both the power steering fluid reservoir AND the cadillac valve. Everything was plumbed back the way it was but I want to confirm it with a diagram that I cannot find. The engines a pullout ECV 6.5 turbo. Any help appreciated,

Verify and double verify the plumbing is correct, anything hooked up wrong or backwards in the system will cause this problem, however, in my case it was a faulty component (cadillac valve).

 

[BenDeez]

That is what I am trying to do. However searching the TM's I can't find the correct way for it, I can find a diagram of the routing with the cadillac valve and without a power steering reservoir and one with the power steering reservoir but without the cadillac valve. I can't find any diagram where both are used, and I have both.
This is the last step in my long 6.5 swap

 

[BenDeez]

This diagram does not show a power steering reservoir mounted. Mine has a reservoir. My pump only has two outputs. So where your caddy valve comes from pump, mine comes from the reservoir. Right or wrong? Am I not supposed to have a reservoir with the Cadillac valve? If I did I imagine I'd need a new pump with three outputs like the diagram?

 

[General Hood]

There is a diagram in TM-2320-280-20-1 unit maint. in the steering control system section

 

[BenDeez]

Yes, the same one as you posted earlier in this thread. It does not show an oil reservoir though. And it shows three lines coming out of the pump. My pump only has two ports.

 

[Wire Fox]

Yes, the same one as you posted earlier in this thread. It does not show an oil reservoir though. And it shows three lines coming out of the pump. My pump only has two ports.

Well, I checked out the diagram that he mentioned and it looks pretty clear to me. You're saying that your setup is different than this? The pump is integral to the reservoir in a standard setup. If you only have two lines versus three and your pump assembly looks different than part E, you should post up some pictures, as you would have something non-standard.