Fan clutch bolts

[Coffey1]

This also happens on hemtt all 4 bolts were loose and coming off you could see through where it mounted.

 

[Suprman]

I have seen the newer style fan clutch do the same thing though. It is strange im sure civilian trucks use the same basic setup. If you cant fix the radiator and charge cooler I do have a pair sitting here.

 

[Smike740]

We did the driveline check with a magnetic dial indicator and was WELL within specs so I'm not worried too much about that.

We also just had the fan clutch off when putting the AC pulley on and thought everything looked good for it too. It is the old style clutch and fan so age may have been a factor. My main concern now is getting the 160lb radiator and air charge cooler out of the truck and then back in once repaired.

I had my radiator out a few months back to pull the camshaft on my truck. If you have an overhead hoist with enough height the radiator can be slid back towards the engine and pulled straight up and out with a little maneuvering.

In my case my hoist wasn't high enough so alot of maneuvering was needed to slide the radiator between the cab and engine once raised higher than the frame. I removed the passengers side tire and pulled the radiator out that side.

 

[Smike740]

I have seen the newer style fan clutch do the same thing though. It is strange im sure civilian trucks use the same basic setup. If you cant fix the radiator and charge cooler I do have a pair sitting here.

I was wondering if the new style clutch and fan had the same trouble. I have seen pictures of the clutch separating as well as the fan separating from the clutch. I was thinking the new fan without the rubber grommet may be better for the case where the fan separated from the clutch.

 

[Adventure Driven]

Suprman

Thanks for this heads up, I have a 94 M1079 that I have had for 1 day, I am trying to learn as much about this truck as posable quickly, I am huge into preventive maintenance and want to check the fan clutch for play, could I get a little clarification on this, I understand what I am checking but do not understand the part when you said " You have to air-to-release the clutch" Is there something locking the clutch tight somehow that I have to release and then check for play? I had truck delivered yesterday and with engine off reached in and grabbed fan, it was not loose at all, but is there more to this check than that?

Thank you soooo much

Seth

The fan clutch bolts seem to have a bad habit of coming loose. You have to air-to-release the clutch and you can rotate it to access the bolts. The fan clutch can come apart and throw the fan and front of clutch assembly. Its not pretty I have seen it twice in the last few months. One person said they heard a bit of rattling in front right before it came apart. I believe this issue can be detected by grabbing the fan blade, with the engine off of course, and giving it a shake feeling for excessive play.

 

[Suprman]

The only test that we know of so far is to do like you did. Engine off grab fan blade feel for play.

 

[Adventure Driven]

Ok, thanks, I will also put a wrench on bolts and check them also, we live in Flagstaff AZ and take our truck out in the middle of the boonies, hate to have a problem miles from no where

Seth

 

[Suprman]

Its not really the fan blade to clutch thats the issue although it dosnt hurt to check. The fan clutch itself just comes apart.

 

[mkcoen]

Its not really the fan blade to clutch thats the issue although it dosnt hurt to check. The fan clutch itself just comes apart.

I think what actually happened to mine was the aluminum hub of the fan disintegrated. The newer fan hubs are steel and rather than being pinched between the outer aluminum piece and the clutch it's actually bolted to the clutch. Much better design.

 

[Adventure Driven]

awesome, that makes sense, where did you get the new clutch and how much was it ?
Thanks
Seth

I think what actually happened to mine was the aluminum hub of the fan disintegrated. The newer fan hubs are steel and rather than being pinched between the outer aluminum piece and the clutch it's actually bolted to the clutch. Much better design.

 

[mkcoen]

awesome, that makes sense, where did you get the new clutch and how much was it ?
Thanks
Seth

I actually bought it from a member here locally but it was the only one he had. I'll try and locate the NSN for it (I think it's in one of the threads but not sure where to point you). The fan I got off eBay.

 

[Adventure Driven]

awesome, thank you very much

Seth

I actually bought it from a member here locally but it was the only one he had. I'll try and locate the NSN for it (I think it's in one of the threads but not sure where to point you). The fan I got off eBay.

 

[mkcoen]

Ok heres pics and the NSN for the clutch. Fans are available on eBay but you'll need to search.

 

[sjohn116]

Looks like 1090-08000-01 might be the newest PN