Fan clutch not working and making noise after replacing actuator

[jvero]

My shutter stat/fan clutch actuator on my M925A2/8.3 went bad and wasn't engaging my fan. I tested the fan clutch and when I put air to the fan clutch it kicked right on. I tried to rebuild the original actuator and that didn't work. So I ordered a new actuator and hooked it up with new fittings today. When it engages the fan clutch, instead of the fan free spinning like it does when the clutch is disengaged, the fan nearly stops all rotation. When I turn the engine off, the fan clutch is making a loud "whining" noise for about 30 seconds or so that sounds like the air is getting to the clutch but the clutch isn't "locking up" like it should. Any ideas what might be wrong here? When I went back and looked at my old actuator, I noticed the fitting coming from the "Out" - the side going to the fan clutch has a mesh of some sort in the opening, almost like like a filter or a baffle to slow the air down to the clutch. Does anyone know why that is there? Is is supposed to be there? If so, could that be causing me fan clutch to not engage properly? Any help or ideas would be appreciated!

One more thing, does anyone know what size the emergency override bolts are to lock in the fan? Not the length, but what thread and pitch size? I lost mine and need to go pickup a couple to replace them. Thank you!

 

[doghead]

The bolts should be found in a parts TM. Then google the nsn and look for the parttarget link. That will give you the bolt info.

 

[jvero]

I can't seem to find the bolts in a parts TM. I have the NSN's from a couple different bolts from the TM that may be the ones, but when I Google the NSN, I can't find any extra info about them. Thanks for your help!

 

[rosco]

I'm not familiar with your truck, but with shutter-stats & fan clutches. Fans don't make noise, unless something is drastically wrong. I doubt that, but what is making the noise? The air? Bearings? Both fans & shutters can be a funny lot. The part that makes them so, and difficult to comprehend, are the controls. Both air or electric controls can be either nominally open", or "nominally closed"! If they are one way, and you think the reverse, they can be a challenge. Sounds like you have the wrong controller. Some controllers use a temperature switch in the water jacket. The switch can be air or electric, or just plain temperature controlled, controlling an air valve or electric switch. Those parts are available at a heavy truck store. Look for a part Number. Be careful about swapping them. The TM might not say which way they work, opening or closing.

 

[70deuce]

My solution to take that troublesome shutter-stat out of the equation.

Post #84

http://www.steelsoldiers.com/showthread.php?83932-Actuator-Air-Fan-Clutch-for-M923a1/page9