AC Clutch Air Gap

[MrMarty51]

Looking online search, also in the forum for the proper airgap when installing the AC clutch.
Most of what I’m seeing seems to be 0.020 to about 0.035 or some such.
Seems about 0.025 should be about right.
Anyone have a better suggestion ?
Speak now because tomorrow it will be too late.

 

[MrMarty51]

Oh yeah, I also see that the nut should be about 12 ft lbs.

 

[MrMarty51]

Oh yeah, I also see that the nut should be about 12 ft lbs.

There was no nut on this AC shaft.
I called the auto salvage and they confirmed that the shaft has no nut.
Had problems with the idler. Installed the electronical electromagnetic unit, the idler was then rough on spinning it.
Removed it all, looked it over. Dressed the shafts some with 600 grit wet or dry.
Reassembled. Idler turned free but just stiff. Installed the clutch cover at about 0.020.
Hooked a can of gas to the low side port, pulled the trigger on the dispensor and charged up the system. AC now blows ice cold. 44* at the bilevel outlet.
Now maybe someone can tell me how many times a minute the clutch is suppose to cycle.

 

[dbrannon79]

not sure on how many time the clutch should cycle, on mine, if the weather is cooler like in the morning when it's around 80 outside and the sun isn't full blast, it will cycle quite a bit. even more often when on the freeway. after the temps are up around 100 deg and hot outside the clutch shouldn't be cycling at all.

of course it all depends on the pressures on the system. connect the gauge manifold and watch the pressures when it cycles off. what are both the low and high pressures like?

mine will cycle off when the low side reaches 25 psi. there is no high side pressure cut off on my truck, only a high pressure fan switch on the back of the compressor and that other high pressure switch on the condenser that makes the recirc door open when the pressure gets too high.

I think GM should have made that switch a cur off switch instead of controlling the recirc door. forcing hot outside air over the evap will make the pressures increase.

 

[dbrannon79]

I ended up messing with my ac a little yesterday since it had been sitting without running, I wanted to double check and make sure it was full of juice. just going off the static pressures and the chart I ended up letting a tiny bit out. I think according to the static pressure chart it should have been 120 psi. it was slightly over so letting some out I stopped at 110-115. tried it out and it was cooling better that the other day! for whatever reason it seems to cool better in the heat of the summer with the system being slightly low!

 

[Twisted Steel Performance]

The cycle of the clutch is dependent on charge level, it will cycle as needed.

 

[MrMarty51]

Okay.
Thank You guys very much.
I wasnt sure if the AC clutch should cycle at all if the system is properly charged.
It seems to Me now, after reading the posts, that it is perfectly normal for the clutch to kick off and on.
It will now be a while before I mess with the AC system again, oil leakage is haunting Me real bad.
Going to pull the engine and replace every gasket and seal, oil cooler hoses too.
Before installing the pig back into its bay, I’ll be scrounging an oil pump drive adapter to spin the pump and pressurize every port in this engine. Maybe let the drill run for a couple hours. Make sure there is no more leaks.

 

[Will L.]

Leak test fix sounds extreme- but I have been there before, I get it.


The ac compressor cycling- this is why with electric fans or THE AKDD FAN MOD electroviscous fan clutch- it is important to not tap the power wire that feeds the compressor to operate them, but instead install a trinary switch. It would work in the mean time if a guy needs, but is far better off using a switch from the pressure. That pressure switch will not cycle so much, and only comes on when the pressure demands- that pressure is from the heat going into condenser.

 

[MrMarty51]

Leak test fix sounds extreme- but I have been there before, I get it.


The ac compressor cycling- this is why with electric fans or THE AKDD FAN MOD electroviscous fan clutch- it is important to not tap the power wire that feeds the compressor to operate them, but instead install a trinary switch. It would work in the mean time if a guy needs, but is far better off using a switch from the pressure. That pressure switch will not cycle so much, and only comes on when the pressure demands- that pressure is from the heat going into condenser.

So that would be hooking the fan control wire to the pressure switch on the pipe going into the condensor ?

 

[Will L.]

Your truck comes stock with a binary switch. You need a trinary switch. It’s all on the thread with the fan clutch that ak diesel driver started, including a descent source for quality parts. You have to evac the system, swap switches, then vacuum and charge.

 

[dbrannon79]

on mine, I used a normal fan pressure switch that's usually present on the 454 models. it's mounted on the back side of the compressor and is pre-set to on a 285 psi and off at 225 psi one side of the switch is fed power when the AC is on, the other side is going into the fan controller though my controller died and now is tied into a separate relay manually enguaging the fan.

The trinary switch is really two switches tied onto one. one made for the fan and the other for compressor cur off. I couldn't find a trinary that would fit the metric threaded port on my condenser, so went with the compressor mounted fan switch. iirc yours has a newer style compressor, mine uses that dreaded pancake compressor that I would love to get rid of and go with something like your truck uses. lol

using this method (trinary or separate fan pressure switch) will also save some mpg's as the fan is not roaring full time when the ac if turned on.

 

[MrMarty51]

on mine, I used a normal fan pressure switch that's usually present on the 454 models. it's mounted on the back side of the compressor and is pre-set to on a 285 psi and off at 225 psi one side of the switch is fed power when the AC is on, the other side is going into the fan controller though my controller died and now is tied into a separate relay manually enguaging the fan.

The trinary switch is really two switches tied onto one. one made for the fan and the other for compressor cur off. I couldn't find a trinary that would fit the metric threaded port on my condenser, so went with the compressor mounted fan switch. iirc yours has a newer style compressor, mine uses that dreaded pancake compressor that I would love to get rid of and go with something like your truck uses. lol

using this method (trinary or separate fan pressure switch) will also save some mpg's as the fan is not roaring full time when the ac if turned on.

Here is a pic of the switch thats screwed to the back of the compressor. Is this the switch thats replaced with the trinary switch ?


Or is it this switch thats above the compressor and takes off to the condenser ?


Would You happen to have the PN for that trinary switch ? And possibly a brand. I’m afraid if I go into the parts store and tell them that I want a trinary switch for the AC compressor/system on My 2000 Chevy with a 6.5 diesel that I’ll get that old wore out doe in the headlamps look again.
Also could You post in a wiring diagram for that trinary switch ?
Thank Yuh very kindly.

 

[dbrannon79]

Here is a pic of the switch thats screwed to the back of the compressor. Is this the switch thats replaced with the trinary switch ?
View attachment 82213

Or is it this switch thats above the compressor and takes off to the condenser ?
View attachment 82214

Would You happen to have the PN for that trinary switch ? And possibly a brand. I’m afraid if I go into the parts store and tell them that I want a trinary switch for the AC compressor/system on My 2000 Chevy with a 6.5 diesel that I’ll get that old wore out doe in the headlamps look again.
Also could You post in a wiring diagram for that trinary switch ?
Thank Yuh very kindly.

both of those look like High pressure cur off switches. iirc the one in the last pic can be replaced with the trinary switch that Will's talking about. on mine, the switch in the first pic that uses a snap ring to mount into the compressor got replaced with the purple colored switch that is a fan switch. mine was originally green and wasn't connected to anything. I found the wire harness later on tucked in and the connector cut off.


if you go the trinary switch route, that switch in the second pic can unscrew and has a shrader valve so you won't loose the freon when replacing. the other one that's held by a snap ring, you'll have to evacuate the system to replace.

I will look up the part number for the switch I used if you want to go the route I did. for goign the trinary switch route, you will have to make sure the threaded port on the line is not metric. that was my issue as I couldn't find a trinary switch that used metric threads for that port.

 

[dbrannon79]

Here is the fan switch I used on my truck. but if you go this route keep in mine it will replace the high pressure cur out switch that is mounted there on the compressor already,

More Information for FOUR SEASONS 35972

doing a google search I ran across this trinary switch that shows to be a M10x1.25 female thread. I cant remember what the size is on the port of our trucks it seems that GM used an odd ball size thread. this would allow you to replace the switch that's in your second pic and wire up the factory wires on one side plus have the second wires for the fan to work. I would need to verify the pressures of this switch to the factory switch that is on your truck making sure those match though. using a trinary switch is no doubt the better way to go. if going the route I did, you loose the safety feature of the compressor shutting down when the system clogs.

Universal Air Conditioner Inc. SW11461C Universal Air Conditioner Trinary Switches | Summit Racing

Free Shipping - Universal Air Conditioner Trinary Switches with qualifying orders of $109. Shop Electrical Switches at Summit Racing.

www.summitracing.com

 

[MrMarty51]

I’d rather not evacuate the AC system. It has been several years since I had the system recharged and at that time He did add some die to the mix.
I do know the switch seal on the back of the compressor has a very slow leak and also the hose down next to the condenser does too. I just want the system to function through the summer so that if the woman and I can make the trip over to the cabin then we can do it in comfort. 112 and 115 F temps can tend to get brutal when traveling without the AC.

 

[MrMarty51]

@Will L.
Do You have a PN for the trinary switch that would work in the place of the switch thats in the condenser high pressure side above the compressor ?

 

[dbrannon79]

I believe I just confirmed the threaded port is in deed m10x1.25 on the line for both your truck and mine too. I wish I had found this when I was searching for one before. the four seasons factory switch is part number 36655. on your truck it's the one in your second pic threaded onto the high side line, for mine, it's threaded onto the condenser behind the grill. it's pressures are on at 295 psi, off at 370 psi.

for my truck, might be the same for yours, this switch simply opens the recirc door in the cab when pressure gets over 370 psi which to me is useless. not sure why GM designed it this way, but replacing this switch with the trinary switch part number UAC SW11461C that had two internal pressure switches 1 side can be wired to the factory "open recirc door) wiring. and 2 can be used to operate the fan clutch. the only thing is I can't seem to verify the pressures this switch turns on or off at. is seems looking at various sites, it might not be the right one to use.

 

[dbrannon79]

Yes I second that notion! @Will L. if you can help find the right trinary switch to use. I need to do some work on my ac soon. we have an upcoming trip to the coast in August. the last couple of days temps got up to 102-104 and my ac could barely function. I need to replace my condenser and look at a compressor replacement as well. when I go to dig off into this I would love to get this part done.

I have been tempted to try using the enviro-safe refrigerant in mine. I have used it in other older vehicles with great success.

 

[Will L.]

I don’t remember the primary location & I don’t have a pickup anymore to verify, and also they changed things through the years. But the binary / trinary switch can be anywhere in the high side of the system. We need someone to verify that is the high pressure binary switch for your truck.

On my pickup I added on to for a secondary coil fan i mounted under the bed, and on my hummer it is on the receiver/dryer.
I took a pic of the one in my hummer- ignore the bent over terminals- they should face straight up.
Search the thread by @ak diesel driver (link help?) - they are on their and so is you tube video links of what to buy and where.
Watch the videos- worth the time. If you can’t DIY the ac - don’t do it yet, get the part and wait till you can go to the ac shop and have them do it. Normal procedure is replacing the dryer every time the system is opened up. I really like vintage air components- a little more pricey (30% ish) but they last forever and the pressures and temperatures are always spot on. If you have a certified vintage air retailer in your area- they are usually good shops to deal with because they are used to non stock applications. This means they also have a real good ability for troubleshooting and getting peak performance. (Insert Tim Alan voice- “More Power ah-hahaha!”)

I would have the entire system up and working perfectly before adding in the Trinary switch in your case. Resist the urge to add sealant to ac systems. That stuff plugs the “leak” that is your orifice tube or txv if you made the upgrade and makes everything perform poorly.

 

[dbrannon79]

@MrMarty51 from what I recall your year model being a 2000, there won't be any pressure sensors mounted on the condenser. iirc in 96 they moved the sensor from the condenser to the high side line behind the compressor. this is the sensor that will make the recirc door open when pressures get too high. you can test this out by turning the key on engine off, turn the ac on. maybe have someone in the cab to listen but I think you'll be able to tell. disconnect the sensor and get you a jumper wire to use on the connector. listen for air flow change in the cab as you jumper the two pins in the harness connector. This sensor also has a schrader in the line so if you have to ever replace it, you can do so without evacuating unless the schrader is bad, the threads should be a metric M10 x 1.25. This is where you could install the trinary switch. Using the same wires on this connector for one side of the trinary, the other two wires for the fan.

I've re-posted your pic of the sensor / switch I'm referring to here.