AC pulley question (1 Viewer)

[Denzel]

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!

 

[Shipwreck]

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.

 

[HillCountryTX]

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!!

 

[Denzel]

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.

 

[HillCountryTX]

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).

 

[Denzel]

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.

 

[96TrailSurfer]

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/

 

[Denzel]

I can finally close this chapter, for anyone interested the problem was (unsure of the precise order of occurrence):
- The snout on the compressor had been warn down allowing the pulley to wobble slightly.
- The pulley bearings themselves were worn. Possible that they had begun to seize which caused wearing on the compressor shroud.
- The magnetic clutch had been extremely roughed up, don't have a picture to show but it was clear the blown fuses were caused from the solenoid windings making contact with the rest of the assembly, when we got it off there were bits of it exposed.

I bought a new clutch before getting the old one off but because of the snout issues, it was useless, I had to replace the compressor which comes with a new clutch anyway. Recommend trying to rule this out before buying a separate clutch!

Also, if you're going to do this yourself, my advice: don't do it blindfolded! There are various snap rings and small pieces that will be very difficult to spot with dirt/grime on them. Pull up the FSM (1996_FZJ80_FSM.pdf | Powered by Box - https://app.box.com/s/ptr6h18kypou9bkeex2o3hn49ah0jbjt, page AC-33 onwards) and pay close attention to diagrams. My replacement magnetic clutch assembly didn't come with any replacement snap rings or shims.

Expensive lesson to learn but I do have an ice cold A/C now. Thanks to everyone who responded!

 

[HillCountryTX]

Glad you got this figured out @Denzel! I'm sure I will be buying a new A/C compressor at some point once my "repaired" one finally gives out. Thanks for your advice and well-documented solution!