AC Compressor Clutch Adjustment / Replacement parts advice. [2002 Envoy SLT ]

[steveO]

I had the A/C compressor bearing go on my 2002 Envoy.
I replaced the bearing but the clutch is slipping when engaged.

The clutch surfaces had quite a bit of wear on them, I cleaned them up before reassembly.
I could easily turn the compressor shaft when I had it apart with my hand and it seem to function OK which is why I decided to replace the bearing.

It must have gotten very hot as I had to clean up a lot of the black epoxy that I assume from the coil.
I check the coil and it was about 3.8 ohms so I think it should be OK

Questions:

Can the clutch be adjusted ? If so how?

Can I just get a new Pulley, Clutch and coil for it.

I didn't see any specific parts on ebay or elsewhere on the web but they reman the compressor so the parts have to be available some where.
I could not see any visible numbers on the unit but I believe it is a Sanden Compressor

Thanks!

 

[The_Roadie]

There's ways to change the shim and adjust the clutch spacing. We discussed it more on the old site. Run this Google search: "ac clutch shim site:trailvoy.com"

 

[steveO]

Thanks for the suggestion.

I did as you suggested and found discussions about changing the shims and even leaving them out.
I have one shim in there, I guess it's a hit or miss kind of thing.
I didn't see any clearance or way to measure it due to the lip on the hub.
I examined the clutch closely when I had it a part and nothing looked damaged with the exception of the surface wear on both the hub and the clutch.
The strength of the magnet is a what holds the clutch engaged so I guess it needs to have a pretty close clearance to get a good engagement
I needed to get it back on the road so I put it back together hoping I wouldn't have anything further to do in the way of adjustments oh well!

Now I have to find a place who sells shims... are they a standard stocked auto part?

 

[Sparky]

Just curious, you said you cleaned up the clutch surfaces... using what?

 

[steveO]

Just curious, you said you cleaned up the clutch surfaces... using what?

I first used brake cleaner to get all the crud off, the venting holes were partially clogged.
I then used the wire wheel from the bench grinder on both surfaces.

 

[steveO]

I took the shim out and it still slips, not as bad but it slips when I accelerate.

Looks like I need a new clutch kit, does anyone have a source for the kit?

I looked on Ebay and the web, there are many Sanden clutch kits for other vehicles but I have yet to find one for the Envoy.

It is near impossible to read any of the info on the compressor what model is it?

 

[steveO]

Purchased a reman clutch off Ebay, apparently new is not an option ...Works fine now.

They provided shims (also hard to find locally), I used one thin shim.
There is more clearance between the clutch face and pulley due to the fact that they resurface both the pulley and clutch faces. The lip that was on the outside is gone, a bi-product of the reman process.

The coil appears to be a used one cleaned up, there were no signs of heat stress, basically a coil is so simple there rarely should be an issue with them, that is unless they get exposed to excessive heat due to bearing failure.

Be sure to have a large straight pair of snap ring pliers in order to reach the snap ring holding the coil in place. The $10.00 universal type won't reach without striking the inner hub. The right tool made it very easy to remove.

There is a small clamp holding the coil wire in place, don't bother trying to remove it, carefully pry it open with a screwdriver just enough to free the wires and then reform it after the new coil is installed. The screw is tough to reach its a Phillips and mine was frozen.

Due to lack of visibility you will need a small magnifying mirror to get a good look inside to confirm that the new snap rings are seated.

I highly recommend replacing the snap ring holding the pulley in place, it show signs of stress when removed and because it's a larger size, not every auto parts store carries them, I had to hunt around to find one. I probably should have asked the reman folks to provide one. The innermost ring holding the coil in place can be reused, there is no stress there.

 

[TequilaWarrior]

Purchased a reman clutch off Ebay, apparently new is not an option ...Works fine now.

They provided shims (also hard to find locally), I used one thin shim.
There is more clearance between the clutch face and pulley due to the fact that they resurface both the pulley and clutch faces. The lip that was on the outside is gone, a bi-product of the reman process.

The coil appears to be a used one cleaned up, there were no signs of heat stress, basically a coil is so simple there rarely should be an issue with them, that is unless they get exposed to excessive heat due to bearing failure.

Be sure to have a large straight pair of snap ring pliers in order to reach the snap ring holding the coil in place. The $10.00 universal type won't reach without striking the inner hub. The right tool made it very easy to remove.

There is a small clamp holding the coil wire in place, don't bother trying to remove it, carefully pry it open with a screwdriver just enough to free the wires and then reform it after the new coil is installed. The screw is tough to reach its a Phillips and mine was frozen.

Due to lack of visibility you will need a small magnifying mirror to get a good look inside to confirm that the new snap rings are seated.

I highly recommend replacing the snap ring holding the pulley in place, it show signs of stress when removed and because it's a larger size, not every auto parts store carries them, I had to hunt around to find one. I probably should have asked the reman folks to provide one. The innermost ring holding the coil in place can be reused, there is no stress there.

Could you post the seller or the listing? My A/C Compressor works for 15 minutes at a time. Dealer says compressor bad. Power gets to the compressor but clutch won't engage. I'm thinking overheated bearing shot the coil - simple fix - replace clutch and coil. Dealer wants $800 for the whole compressor replacement (with recharge). I'd rather do the clutch/coil assembly myself.

 

[steveO]

Could you post the seller or the listing? My A/C Compressor works for 15 minutes at a time. Dealer says compressor bad. Power gets to the compressor but clutch won't engage. I'm thinking overheated bearing shot the coil - simple fix - replace clutch and coil. Dealer wants $800 for the whole compressor replacement (with recharge). I'd rather do the clutch/coil assembly myself.

On Ebay look for Air Parts.

But before you purchase the clutch;
Take the belt off and turn the pulley by hand, if it moves freely and doesn't feel tight and rough then you don't have a clutch / bearing issue.
If you turn the center part (clutch disk) and it does not move freely you might have a bad compressor.

Just my two cents for what it's worth.

 

[TequilaWarrior]

On Ebay look for Air Parts.

But before you purchase the clutch;
Take the belt off and turn the pulley by hand, if it moves freely and doesn't feel tight and rough then you don't have a clutch / bearing issue.
If you turn the center part (clutch disk) and it does not move freely you might have a bad compressor.

Just my two cents for what it's worth.

Dealer just checked out everything - said charge was good, compressor operation was good, even bearing was good. The clutch won't engage and the will not service the clutch. The service manager (friend of mine) literally said the only thing wrong is the clutch won't engage; which I take to mean the coil isn't pulling the clutch to contact. It literally works for 15 or so minutes or whenever the temperature is below 80 degrees. Others have described a weak or nonfunctioning clutch coil at higher temps - this is what I presume is wrong with mine and I'm willing to take a chance on replacing just the coil while cleaning the clutch surfaces.

I found two sellers: airpartsinc and cool_air_parts. These are the only two I found that make any real sense as possibly having what I'm looking for, but don't currently list anything for the GMT360. cool_air_parts lists a complete replacement compressor with dryer, but that's what I'm trying to avoid.

Anyone have pictures of what the coil looks like off of the compressor?

 

[Sparky]

Don't clean the clutch surfaces. You'll likely end up just removing the clutch material and then you'll need a whole new clutch

Here is a generic picture of a clutch coil.

View attachment 20760

 

[steveO]

Don't clean the clutch surfaces. You'll likely end up just removing the clutch material and then you'll need a whole new clutch

The clutch is metal to metal engagement there is no clutch material.
Unless you remove the hub you won't get a look at the inside of the coil which is the part that you want to see to verify if heat damage is the cause.

As far as not finding a listing for the clutch, I contacted them and they put it up for me as a private listing.

I'm suspicious of the the coil diagnosis as they are a work or don't work kind of device.
My clutch overheated and damaged the coil, overall the hub and clutch surfaces were in rough shape as well.
The bearing was clearly the cause of my failure, too bad I didn't catch it earlier,would have spared myself the expense of the reman clutch.

There is a some sort of thermal protection in the compressor that prevents the coil from activating when the compressor overheats that could be shutting the compressor down on you.
If the coil overheated you would see black epoxy around the outside and inside of the hub it makes a mess.
There is a way to jump the relay to engage the compressor manually but I don't know exactly how to do it to verify if the coil is the issue.

 

[Sparky]

If the coil overheated, the insulation on the coil wires - which likely is nothing more than an enamel coating like motor windings use - can melt in spots to short part of the coil and make its magnetic attraction weakened when energized. So technically it could still "work" but not with full attraction, which could lead to a weak engagement and possibly clutch slippage. At higher temperatures the wire expands a little bit (like all materials do when warmed up) and it is possible that the expansion causes an internal short or circuit breakage. I've seen windings get damaged like that before.

I'm not going to say that is certainly the issue, but if the techs properly tested the other stuff and the coil is all that's left, well, it stands to reason that the coil is the culprit. It wouldn't hurt to check the relay too. Check to be sure you're getting power to the clutch connector even when the clutch stops engaging would be a surefire way to pinpoint the coil as the culprit or not.

 

[steveO]

It wouldn't hurt to check the relay too. Check to be sure you're getting power to the clutch connector even when the clutch stops engaging would be a surefire way to pinpoint the coil as the culprit or not.

Agree

 

[TequilaWarrior]

If the coil overheated, the insulation on the coil wires - which likely is nothing more than an enamel coating like motor windings use - can melt in spots to short part of the coil and make its magnetic attraction weakened when energized. So technically it could still "work" but not with full attraction, which could lead to a weak engagement and possibly clutch slippage. At higher temperatures the wire expands a little bit (like all materials do when warmed up) and it is possible that the expansion causes an internal short or circuit breakage. I've seen windings get damaged like that before.

I'm not going to say that is certainly the issue, but if the techs properly tested the other stuff and the coil is all that's left, well, it stands to reason that the coil is the culprit. It wouldn't hurt to check the relay too. Check to be sure you're getting power to the clutch connector even when the clutch stops engaging would be a surefire way to pinpoint the coil as the culprit or not.

I don't know if they realized it or not, but that's pretty much what the tech did. "Charge good. Power at compressor clutch - no clutch engagement" was the notes I got back on the work order.
They didn't mention the bearing, so I will be checking that out - but I do suspect that the coil is the culprit from the notes. That's why I was asking. I'll get ahold of Air Parts and see if they can't help me out with a coil.

 

[c good]

I had this exact problem. I was the one that finally solved the problem (with the input and wisdom of many other T.V'ers) on the old site by cooling the compressor with a spray bottle when it got hot (over 80 degrees ambient temperature). It was a weak/going bad coil assembly. When it got hot it would fail even with power confirmed at the coil. When it cooled down, it would work perfectly. Unfortunately I could not find a replacement clutch/coil assembly. I ended up getting a low mileage unit out of a salvage yard. Replaced the whole compressor and evac/recharged the system. That was a couple of years ago and all is working perfectly still. HTH. c good

P.S. I dug out my old original compressor and it is a Sanden Model 3450. It also says TRSA12, GM part number 15070473. HTH