Automotive Air Conditioning Information Forum (Archives)

mtwask01 on Tue July 24, 2012 7:32 PM

Year: 1995
Make: Jeep
Model: Cherokee
Engine Size: 4.0L
Refrigerant Type: R-134a
Ambient Temp: N/A
Pressure Low: N/A
Pressure High: N/A
Country of Origin: United States

Hello,

I'm new to this forum and this is my first post. My question is regarding the clutch on a Sanden SD7H15. I took the clutch and the front plate off of the compressor to change the o ring on the plate and the shaft seal. I carefully followed all directions and made sure the parts were back in their correct order. I tightened the front plate bolts until they felt tight enough (I didn't go crazy with the tightness). I then installed the clutch, and when I finally got the hub on, I couldn't turn it by hand. I tried briefly turning it with a socket but stopped because I was afraid of destroying the threads on the shaft and rounding the hub bolt. I took the front plate off again and nothing is seized; the nose bearing and the swash plates turn as they should. I'm running out of ideas, if nothing internal is seized, what then is the problem? Sorry for this long post, but I need some advise. Any help is greatly appreciated.

Thanks,
Matt

GM Tech on Tue July 24, 2012 9:34 PM

So did the shaft turn prior to your adventure? My guess is it did not......Why did you choose to replace shaft seal? was old clutch smoked? due to a seized compressor?

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

mtwask01 on Tue July 24, 2012 9:48 PM

Yes, the shaft did indeed turn before disassembly and could be turned by hand. My reason for opening up the compressor was because the front housing o ring was leaking oil. I replaced the shaft seal because there was a new one in the kit and though I might as well replace it. The old clutch worked fine too, I just replaced it for preventative maintenance, but it had no issues engaging/disengaging. My thought was I did something wrong but when I took it apart again, all the internal parts would freely move.

GM Tech on Wed July 25, 2012 8:01 AM

Double check your work- if compressor binds after re-assembly- you may have dropped out a thrust washer or two- unknowenly- then tightened it together without it in place, and it binds- look on internet for internal breakdown diagram of your compressor- something is amiss..

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

ice-n-tropics on Wed July 25, 2012 5:08 PM

Matt,
USE A SHAFT PROTECTOR WHEN REMOVING THE CLUTCH PULLEY ROTOR AS NOTED IN THE SERVICE MANUAL.
This causes the axial force to be applied against the aluminum front housing nose instead of the end of the shaft.
Forces against the shaft can cause the shaft to be pressed back into the internal parts (planet plate and cam rotor) and jam up the compressor internals.
I'm out of this Texas heat for August and off to Breckenridge.
Hope this helps next time,
hotrodac

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

mtwask01 on Wed July 25, 2012 10:34 PM

Yeah, I know I should have used a shaft protector, but I didn't have one. I used a two jaw puller to remove the clutch pulley and it came right off. I took the front plate back off the compressor to see if I missed anything and all the components were in place and once again all the internal parts could move. I put the plate back on as well as the clutch. I took a spanner wrench to the hub and tried turning it. At first, it was very difficult to turn; I could only get it about 1/8 of a turn. I moved it back and kept trying to move it. It started to free up where I could turn it about 1/3 of the way. After continuing to play with it, I now have it to where I can completely turn the hub with the spanner wrench without a whole lot of effort. I still, however, cannot quite turn it with my hand, but I figure since it can be turned and it is getting easier to turn it, the compressor is not seized and the engine would most likely be able to turn it and loosen it when I eventually finish my a/c job. I greatly appreciate the advise both of you have given me. What do you guys think, would it be okay to put this compressor in use?

Thanks,
Matt

mk378 on Thu July 26, 2012 8:36 AM

Sounds like the back of the clutch plate is touching something, like the seal. That could happen if the seal is not all the way in or it is the wrong thickness.

mtwask01 on Thu July 26, 2012 1:47 PM

Update: I can now turn the compressor by hand. It's still not as easy as before but it really seems to be loosening up. I've been adding small quantities of oil while rotating it, it seems to be helping. I probably should have mentioned in my original post that the compressor had been almost completely drained of oil and mounted upside down for the past several days. I'm really happy it's getting easier to turn, it had me worried for a while.