AC pulley (rotor) and stator help

[cahill]

I need a little help from the AC gurus here on mud. My 97 LX450 started having a bit of play in the AC rotor. You could hear in knock a bit when the engine was running and was a little worse when the AC kicked on. I tried tightening the belts and it didn't help too much. I then did a bit of re-reading and decided it may be the bearing in the rotor so I decided to replace that with a NSK bearing.

When I took the rotor off, I noticed there was a gasket like material on the inside of the rotor. It was only on part of the rotor and looking at the stator it was clear that there was the rest of it was fused on the stator surface where it would mate with the rotor. I wasn't sure what to make of it. I thought it may be a clutch like material on the stator that has worn down over time vs melted ac belt powder that fused to the surface over 20 years of use.

The old bearing seemed fine. There was no play in the rotor/bearing once it was taken off the ac compressor. I decided to try the new bearing directly and there was still some play of the bearing on the cone of the AC compressor. The cone didn't seem overly worn so I decided to just replace the bearing anyway and re-assemble it. On reassembly with the new bearing the rotor had much less play and was comparable to my other vehicle. I am not sure why it had play before but think it may be due to the new snap ring being slightly thicker as the old one did have signs of wear.

After re-assembly, I started it up and there was immediately a bit of a squeaking sound and smoke from the stator/rotor area. I initially thought it was the belt slipping but the belt was fine. I shut it down, checked for play etc and couldn't find anything so I started it back up and there was no more squealing or smoke. There was no longer any play in the pulley. The ac works in the vehicle (it worked before too) but now the ac does not seem to idle on and off on it's own as it used to. If the ac is on, the ac clutch stays engaged unless turned off with the button on the dash - at which point the ac clutch disengages (well mostly, it does rotate intermittently and very slowly for about 10 seconds and then stops like it is still catching a bit).

The other odd thing is that the ac clutch and rotor are very hot to the touch. I compared it to my 97 LC and the ac does cycle on and off like it is supposed to and the rotor and clucth are warm but won't burn your hand if you touch it after it has run for a bit.

So, my questions are:

Does the stator have a clutch like or gasket like material from factory? Would removing the flaked off material from the rotor cause the rotor/stator to now be slipping and get hot? It doesn't seem to be noticeably slipping in opperation other than that first 10 seconds when I started it the first time. Would any of this cause the AC to no longer cycle on and off like it used to? I am guessing the slight difference in thickness loss may be affecting the AC clutch since it doesn't disengage as crisply as before.

I am planning to buy a new stator and see if that fixes it, but am mostly looking to learn and also see if I may be needing to order anything else at the same time Thanks for any insight and help. Here are the photos incase they help.


AC pulley play (look at the bottom of the pulley between the pulley and the clutch and you can see the gap/light when comparing the 2 photos - this is what I was trying to fix and did fix but introduced new problems

Here is the inside of the rotor with the original bearing. Inside the rotor you can see the areas that had some gasket or clutch material that were scraped off.

Here is the stator that shows much better the material I am talking about and questioning what it is.

And here is a piece of it that flaked off.

Thanks again.

 

[BILT4ME]

I need a little help from the AC gurus here on mud. My 97 LX450 started having a bit of play in the AC rotor. You could hear in knock a bit when the engine was running and was a little worse when the AC kicked on. I tried tightening the belts and it didn't help too much. I then did a bit of re-reading and decided it may be the bearing in the rotor so I decided to replace that with a NSK bearing.

When I took the rotor off, I noticed there was a gasket like material on the inside of the rotor. It was only on part of the rotor and looking at the stator it was clear that there was the rest of it was fused on the stator surface where it would mate with the rotor. I wasn't sure what to make of it. I thought it may be a clutch like material on the stator that has worn down over time vs melted ac belt powder that fused to the surface over 20 years of use.

The old bearing seemed fine. There was no play in the rotor/bearing once it was taken off the ac compressor. I decided to try the new bearing directly and there was still some play of the bearing on the cone of the AC compressor. The cone didn't seem overly worn so I decided to just replace the bearing anyway and re-assemble it. On reassembly with the new bearing the rotor had much less play and was comparable to my other vehicle. I am not sure why it had play before but think it may be due to the new snap ring being slightly thicker as the old one did have signs of wear.

After re-assembly, I started it up and there was immediately a bit of a squeaking sound and smoke from the stator/rotor area. I initially thought it was the belt slipping but the belt was fine. I shut it down, checked for play etc and couldn't find anything so I started it back up and there was no more squealing or smoke. There was no longer any play in the pulley. The ac works in the vehicle (it worked before too) but now the ac does not seem to idle on and off on it's own as it used to. If the ac is on, the ac clutch stays engaged unless turned off with the button on the dash - at which point the ac clutch disengages (well mostly, it does rotate intermittently and very slowly for about 10 seconds and then stops like it is still catching a bit).

The other odd thing is that the ac clutch and rotor are very hot to the touch. I compared it to my 97 LC and the ac does cycle on and off like it is supposed to and the rotor and clucth are warm but won't burn your hand if you touch it after it has run for a bit.

So, my questions are:

Does the stator have a clutch like or gasket like material from factory? Would removing the flaked off material from the rotor cause the rotor/stator to now be slipping and get hot? It doesn't seem to be noticeably slipping in opperation other than that first 10 seconds when I started it the first time. Would any of this cause the AC to no longer cycle on and off like it used to? I am guessing the slight difference in thickness loss may be affecting the AC clutch since it doesn't disengage as crisply as before.

I am planning to buy a new stator and see if that fixes it, but am mostly looking to learn and also see if I may be needing to order anything else at the same time Thanks for any insight and help. Here are the photos incase they help.


AC pulley play (look at the bottom of the pulley between the pulley and the clutch and you can see the gap/light when comparing the 2 photos - this is what I was trying to fix and did fix but introduced new problems
View attachment 3621777



View attachment 3621778

Here is the inside of the rotor with the original bearing. Inside the rotor you can see the areas that had some gasket or clutch material that were scraped off.

View attachment 3621780

Here is the stator that shows much better the material I am talking about and questioning what it is.

View attachment 3621782

And here is a piece of it that flaked off.

View attachment 3621783

Thanks again.

You really just did all that and don't understand what that is?

 

[cahill]

I've never worked on any of this before and just learning as I go. I have my guess that the play was from the wear on the snap ring since the bearing actually seemed fine and both the new and old had the same amount of play on the cone before installing the new snap ring but this is just a guess. I have never seen an ac clutch/pulley stator assembly dissassembled until today so I don't know what they are supposed to look like.

 

[Rusty Marlin]

Did you check the clearance gap on the clutch when you reinstalled it?
Its supposed to be .006" or less. (2 peices of receipt paper.)

 

[DIRTBIKEUSA]

The clutch on the AC compressor is slipping because it’s burned up. You need a new compressor or at the very least a new magnetic clutch. The noise you are hearing is the compressor chattering internally because the clutch keeps loading and unloading the system. The new noise is the clutch slipping. That my educated guess..

 

[Irish Reiver]

Rockauto for the win

 

[DIRTBIKEUSA]

Rockauto for the win

View attachment 3622035

That’s a great price! Don’t forget the 5% discount code..

 

[jpoole]

It's possible/likely that the nose of the compressor, where the bearing mounts, is worn. What can happen is a little wear on the nose of the compressor allows the part of the clutch that rides on the bearing to operate at a slight angle. When one part of the clutch is angled (compressor/nose end) and the other is straight (input shaft end) then the clutch friction surface will have to accommodate the difference which means extra friction between the two clutch surfaces, squeaking, heat, etc..

One way to see if you have the above situation going on is to use a feeler gauge to compare the clutch gap side to side, when the clutch is disengaged. The tension of the belt will pull the compressor side of the assembly over, removing any slack caused by wear, and the variance in gap side to side can be large enough to be visible at a glance.

It's possible to remedy the above situation and I've done this on an 80 by using aluminum repair rod (available at HarborFreight, etc.). I cleaned the nose and then with a torch and the rod I built up the compressor nose surface where it was worn. After that I filed/sanded the added material back to where it should be and when re-assembled most of the angle was gone. This kept the AC going during a hot spell when I didn't have time to do a full system refresh and I had no AC issues for the few months after this repair up until I replace the compressor/etc.. Heating the nose seems likely to compromise the shaft seal etc. so this repair isn't that great of an idea I don't think but it could be worth trying in some situations and at least has worked once.

My recommendation is to replace all of the major components in the system, clean the system out and recharge it from scratch so that you can enjoy an as new AC system. It's not a very difficult or expensive project. Here is my writeup on the process including the needed parts, prices, recharge process etc.

FZJ80, R134A Air Conditioning System Rebuild How To

forum.ih8mud.com

 

[cahill]

Did you check the clearance gap on the clutch when you reinstalled it?
Its supposed to be .006" or less. (2 peices of receipt paper.)

I didn't re-check the clearance when re-installing the clutch. I just used the same shim that was there since it was working before. I can check it and see.

 

[cahill]

@jpoole, I'll check to see if there is any gap on the pulley and see if it is canted by the pulley tension. It is interesting that before changing the bearing and circlip, I could rock the pulley easily by hand even with the belt on. I can't do that now and the noise it had been making is now gone. Any thoughts on what that material is that was flaking off?

I was hoping not to replace the whole system if I can avoid it, but if I do have to replace the pump and open up the system, then yes, replacing the components in the system is a good idea.

 

[cahill]

The clutch on the AC compressor is slipping because it’s burned up. You need a new compressor or at the very least a new magnetic clutch. The noise you are hearing is the compressor chattering internally because the clutch keeps loading and unloading the system. The new noise is the clutch slipping. That my educated guess..

I am pretty sure the noise I was hearing was the pulley itself knocking against the clutch as it wobbled back and forth. It was a pretty obvious wobble. It did get a lillte louder when the ac engaged so there could be the compressor chattering too. That noise has all resolved now and the play in the pulley is gone with the new bearing and clip. I do think the clutch is probably shot though.

 

[jpoole]

Sounds like in your case the compressor nose was ok but the bearing had introduced the slop I described. The clutch has some friction material that is worn away on yours based on the pics/description. You can get a clutch assembly I'm pretty sure but as I recall it's hard to find and the price is close to an entirely new compressor.

Depending on the overall age and condition of your system if you are replacing the compressor you are on the slope to replacing anything else that may need updating so that you only have to open it once. Really depends on how much time $$ you want to put into the current system / old parts vs. just replacing them and starting over.

 

[ZackR]

If it was me I'd replace the compressor and clutch with new.

Since you will have to open the system you can then swap out the drier, pull the evaporator and clean it out, swap in a new expansion valve and put it all back together. A local AC shop can vacuum/charge it back up for you (or you can DIY). It's amazing how well the AC works once the evaporator is cleaned up.

 

[cahill]

I probably will have to go this route and refresh the whole system. It blows pretty cold but I am sure it would be colder if the evaporator was cleaned.

This afternoon I took a look at it again. I don't have a depth gauge to check the clearance on the clutch but have some feeler gauges. As @jpoole suggested and suspected there is a gap difference of about .02" between the clutch and rotor when measuring the gap on opposite sides of the axis of belt tension.

I took it apart again and there was definitely some burnt material on the clutch. I cleaned that off and put it back together again and used the old snap ring to compare play and the pulley was much more wobbly. I put the new one back on and buttoned things up and re-tried the ac. There is a little noise from the ac when the clutch kicks on but there is no longer the odd phenomenon of the ac clutch failing to cycle. It is back to cycling like it should. I am sure it won't be long before it starts making noise again. This at least buys me time to get the parts to refresh the system and not be driving around sounding like I have an engine knock