Automotive Air Conditioning Information Forum (Archives)

Jason3 on Sat August 07, 2010 2:15 AM

I've got an older GM car that has the Harrison compressor. I believe it is the R4 model.

I had gotten the clutch wet some when changing coolant, and it sat for a few days.

I went to burp it a few days later of it sitting. I started it with heat on and I noticed the clutch was smoking some. It looked like the clutch was hanging up as it should be spinning. But looked as if it was gummed up as it would turn some, then stop, then turn some more. The clutch got real hot as the clutch plug melted some. And I noticed an area of the belt was really hot after I pulled the belt off, which I guess it got hot from sitting still on the clutch as I had to get a ratchet to pull the belt off.

I can turn the clutch by hand, so that tells me the compressor isn't seized. And I can turn the pulley, but it has resistance. I believe the pulley should turn freely like turning a wheel off the ground. On another GM car I have, I can easily spin the pulley.

So, my guess is the water caused the pulley bearing to start to seize as it sat still for a few days. And when the clutch engaged, it put too much drag on the pulley as it's already got resistance, and it thus caused the pulley to not want to turn. Thus the belt ran on the stopped pulley generating the heat and probably the smoke I saw.

So, I'm guessing that sounds like a bad clutch? Does anyone know of any writeups on how to pull a Harrison R4 clutch? As I believe you need special tools unlike a Nippondenso compressor which doesn't need anything but a ratchet and snap ring pliers.

mk378 on Sat August 07, 2010 8:40 AM

Pulley should spin freely with the belt off. So your bearing is shot. If the compressor got hot enough to make the shaft seal leak (or if it was leaking all along) you might consider replacing the whole unit. A special tool is required to remove and install the clutch plate. It is pressed onto the shaft, not splined, so it has to be forced on and off. The same system is used on almost all GM compressors, but depending on how old it is the threads on the end of the shaft may be American or metric, so there are two kinds of "GM clutch plate installer" tools. Once the plate is off you can just remove the snap ring and pull the pulley/bearing with a gear puller.

Jason3 on Sun August 08, 2010 9:16 PM

Quote
Originally posted by: mk378
Pulley should spin freely with the belt off. So your bearing is shot. If the compressor got hot enough to make the shaft seal leak (or if it was leaking all along) you might consider replacing the whole unit. A special tool is required to remove and install the clutch plate. It is pressed onto the shaft, not splined, so it has to be forced on and off. The same system is used on almost all GM compressors, but depending on how old it is the threads on the end of the shaft may be American or metric, so there are two kinds of "GM clutch plate installer" tools. Once the plate is off you can just remove the snap ring and pull the pulley/bearing with a gear puller.

I don't know if the shaft seal is leaking. I just know that can happen if it gets too hot, but I'm hoping that didn't happen as I didn't run it long. Sure does suck to change the coolant, and get the clutch a little wet just to cost you an extra several hundred $ for no reason.

I sprayed the front clutch openings with Kroil. And that freed the pulley up to where I can easily spin it. I've got the kit. So, I'll go ahead and at least pull the clutch plate off, clean it up, throw an old belt on and see what that does. The key is knowing how far to press the clutch plate back on. I assume a .020" air gap and 10 ft/lbs torque on the clutch plate bolt.

The kit didn't come with instructions. But I say I can figure out how to pull and install it as I say it is something similar to a harmonic balancer or power steering pulley.

Jason3 on Fri August 13, 2010 5:05 AM

With the clutch engaged. I can hear a grinding sound with my stethoscope. I have heard an overcharge could damage the clutch.

Anyways, could a shop be able to tell whether the grinding sound is coming from the clutch or compressor?

As a local shop I had the AC recharged/checked a few months ago said they had a special on AC check for $20. They said they check leaks, and I asked if they could check the grinding noise and tell me where it was coming from the clutch or compressor. They said they could. But I'm betting they'd just come and tell me what I already know that there is a grinding and the clutch or compressor is bad and it will be a waste of money as I already know that.

This shop has before told me my car checks out fine, just for me to find cut brake lines or worn rotors below throw away spec, or large oil leaks. So, I do question their ability to actually check things out.

Edited: Fri August 13, 2010 at 5:06 AM by Jason3