AC pulley question

Joined
Sep 5, 2022
Messages
8
Location
Sydney Australia
PXL_20220925_020256674~2.jpg


Rookie here, just changed the fan belt, came out to check everything was spinning and noticed this inner part on the AC pulley slipping, sometimes spinning with the pulley sometimes not. I'm guessing this just needs tightening up but wanted to come here to make sure, and also to ask what that part is actually doing. Is this meant to spin with the rest of the pulley? Is tightening the bolt on the face of the pulley the appropriate fix? The AC was off at the time, also with a blown fuse which may or may not be related. TIA!
 
Solution
That is the AC pulley clutch. It is electromagnet contolled and may turn on and off depending upon the whether the AC is on and at what temperature setting you have the slide control set to in the cab. Perfectly normal to turn on and off.
Yes, double check the torque value on the mounting nut, but it is fairly low; 18 N m if I recall.
Hard to tell from your picture, but yours looks like it is well worn and the rubber insulator may have some cracks. If that is the case, and it truly is cracked and not engaging properly when the AC is on, it needs to be replaced.
Joined
Nov 13, 2002
Messages
680
Location
The Saratoga slums, CA
That is the AC pulley clutch. It is electromagnet contolled and may turn on and off depending upon the whether the AC is on and at what temperature setting you have the slide control set to in the cab. Perfectly normal to turn on and off.
Yes, double check the torque value on the mounting nut, but it is fairly low; 18 N m if I recall.
Hard to tell from your picture, but yours looks like it is well worn and the rubber insulator may have some cracks. If that is the case, and it truly is cracked and not engaging properly when the AC is on, it needs to be replaced.
 
Solution
Joined
Sep 5, 2022
Messages
8
Location
Sydney Australia
Hey @Denzel , I have an almost identical issue as what you are describing. Please see my thread at: 1991 HDJ81 A/C Compressor noise and slow spin - https://forum.ih8mud.com/threads/1991-hdj81-a-c-compressor-noise-and-slow-spin.1294616/

I would be very interested to find out what your solution ends up being for this. Thanks!!

Thanks for linking this, that is very similar to my problem but mine was spinning more intermittently, I'm thinking it might be a dying clutch. After my post I had to make a ~5 hour drive home and the clutch seems to sit still now. I haven't been able to properly test the clutch since I'm still having a fuse blowing problem when I turn on the AC. Not totally sure what that could be caused by, but I'd hazard a guess it's the clutch over-drawing. I'll look at it with a multimeter soon and will hopefully quickly find something simple but based on research (such as this thread) I suspect it's the clutch. Apparently as they die and seize up they can short. I'll post updates here after I have a closer look.
 
Joined
Nov 29, 2016
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216
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Arkansas
I think you are exactly right @Denzel with the clutch causing the A/C fuse to blow. The fuse blowing has not happened to me yet, but I'm pretty sure the clutch will continue degrading over time and evenutally I'll be in the same situation as you. I've decided to replace the clutch on my Denso 471-1433 A/C compressor. Just ordered the clutch kit (includes the shims as well) and it should be to me in a week or so. I am going to attempt to do the clutch replacement with the A/C compressor still in the vehicle on my HDJ81 (i.e. 1-HDT).
 
Joined
Sep 5, 2022
Messages
8
Location
Sydney Australia
I think you are exactly right @Denzel with the clutch causing the A/C fuse to blow. The fuse blowing has not happened to me yet, but I'm pretty sure the clutch will continue degrading over time and evenutally I'll be in the same situation as you. I've decided to replace the clutch on my Denso 471-1433 A/C compressor. Just ordered the clutch kit (includes the shims as well) and it should be to me in a week or so. I am going to attempt to do the clutch replacement with the A/C compressor still in the vehicle on my HDJ81 (i.e. 1-HDT).
I've still not been able to properly diagnose the clutch but I've discovered the bearings are definitely shot, I'm guessing the tension from the new belt put the final nail in the coffin (hopefully not from over tension but I think I'll be getting my hands on a tension gauge for next time). They make a horrendous noise and have some noticeable free play and for our trip last weekend I just ran without the A/C belt all together. Will probably order a new clutch soon, we're heading into summer down here so this is about to become a critical part...

Keen to see how your replacement goes, will hopefully be able to the same to mine.
 
Joined
Aug 5, 2016
Messages
91
Location
Vancouver, Canada
I've still not been able to properly diagnose the clutch but I've discovered the bearings are definitely shot, I'm guessing the tension from the new belt put the final nail in the coffin (hopefully not from over tension but I think I'll be getting my hands on a tension gauge for next time). They make a horrendous noise and have some noticeable free play and for our trip last weekend I just ran without the A/C belt all together. Will probably order a new clutch soon, we're heading into summer down here so this is about to become a critical part...
Keen to see how your replacement goes, will hopefully be able to the same to mine.

I would suggest to start by replacing the rotor (pulley) bearing. See my write up at HOWTO: AC Rotor (Pulley/ Clutch) Bearing Replacement In Situ (1HDT/FT) - https://forum.ih8mud.com/threads/howto-ac-rotor-pulley-clutch-bearing-replacement-in-situ-1hdt-ft.1297198/
 

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