A/C Compressor question...

[ericboutin]

This weekend we went on a camping trip and whenever we would be at a stop idling the a/c compressor would start squealing like crazy. At first I wasn't sure what the heck it was but when I would switch off the a/c it would quit. So I'm assuming that my compressor has bit the dust. It's still blowing cool but not cold...at first I thought maybe it was just needing a re-fill....which it may be needing??
My question is besides the obvious that I have no way to capture the 134 (it's been converted) is there anything special to changing this thing out. Can I do it myself here at the house like you would change out an alternator or is there something special that needs to happen. I can prob change it out myself and re-fill it with 134 from Wal-Mart (sorry Mel) a whole lot cheaper than having someone else do it. Thanks in advance!

 

[Optikalillushun]

squeeling could be the clutch starting to go. at work we had one that would squeel like a pig whenever the AC clutch kicked on. about 20 miles later it was begining to sieze...

 

[HammerDown]

Yep sounds like the clutch...I replaced mine some 12 years ago. > easy!

 

[BigRigTech]

Mine would do that too on my 96...New clutch fixed the issue....If it's not blowing cold then I doubt a clutch would fix it, might be down on charge as well. I recharge mine every spring, holds 150psi no problem for an hour but it leaks out in the winter. ...Probably the pump shaft seal weeping....The 134A is free for employees so I don't mind...

 

[MIDNIGHT RIDER]

Yep sounds like the clutch...I replaced mine some 12 years ago. > easy!

Are the 1985 compressors the same ??

My 1985 half-a-million-mile plus original compressor still works like new.

Would it be advisable (this winter, when I have all winter to fix whatever I mess up) for me to replace the clutch bearings ??

Are there also replaceable bearings in the compressor ??

Is there a TECH article on doing this ??

Thanks.

 

[Mr_Roboto]

The clutch can be repalced without opening the system.

Even if you were to vent the freon to the atmosphere (which you should not) it needs to be evacuated before recharging. A/C will not work with air in the system.

 

[flatlander]

Like said, you can change the clutch on the compressor. You'll need snap ring pliers as I recall.

If the compressor is bad, you might be able to shut the valves on the 2 lines to the compressor and save your charge. Don't take that as gospel, because I've been known to say and do stupid things.

 

[Agnem]

Bet you can't buy the clutch at tramlaw!

 

[Dirtleg]

As has been said you can do the clutch yourself without much trouble. Infact redoing the whole system including changing out the compressor, drier and orifice valve only takes about an hour. I had to do mine AGAIN today.

I must confess that I am now in Mels camp on buying factory parts. I hate it that they are sooo damned expensive but the auto crap retailers parts are just not worth installing in the first place. My 10 month new craptastic A/C compressor started leaking 134 from the shaft seal. I recharged it so I could make a trip last week but only made it 50 miles from home when the clutch hub bearing failed and essentially melted the belt. I was pulling my gooseneck at the time so a tow truck was not an option. Thank God for good friends with work trucks. We put my truck on the trailer and towed it back with my buddies truck. In turn I fixed his A/C today. Hadn't worked for 3 years.

End of hijack.

The most important aspect of the repair is getting all the air out of the system by using a vacuum pump. I would locate the leak first then decide whether or not to change out the hub or the whole compressor. One hint on leaks. The schrader valve on the high and low pressure ports can work themselves loose. Simply tightening them a little can stop the leak when this happens. I would check them first before doing any investigating elsewhere. Also don't use the blacklight dye they sell. Get a spray bottle with water and dishsoap in it and spray all the possible places where you could have a leak. If it is leaking it will foam up where the leak is at.

Good luck.

 

[RLDSL]

This weekend we went on a camping trip and whenever we would be at a stop idling the a/c compressor would start squealing like crazy. At first I wasn't sure what the heck it was but when I would switch off the a/c it would quit. So I'm assuming that my compressor has bit the dust. It's still blowing cool but not cold...at first I thought maybe it was just needing a re-fill....which it may be needing??
My question is besides the obvious that I have no way to capture the 134 (it's been converted) is there anything special to changing this thing out. Can I do it myself here at the house like you would change out an alternator or is there something special that needs to happen. I can prob change it out myself and re-fill it with 134 from Wal-Mart (sorry Mel) a whole lot cheaper than having someone else do it. Thanks in advance!

OK, BACK to square one here. Before resorting to all these surgical measures, you live in a hot , humid climate. You have a slushbox so you have even more heat buildup at idle. I bet your fan clutch probably has quite a few miles on it and doesn't pull squat at idle and you don't have an electric fan rigged to your ac.
When head pressure builds up from excess heat at idle the clutch will start to slip. VERY common occourance around here. I put an electric pusher fan rigged to come on with the ac compressor through a standard Bosch relay on everything that rolls around here that doesn't come with factory E fans or you don't have AC in traffic. Trick I learned many years ago working in an AC specialty shop.

When you put a pusher fan on there it drops the head pressure on the compressor DRASTICALLY at idle in traffic ( not to mention cooling other things down a bit ) and it condenses the refrigerant at a decent rate to where you can actually get some decent cooling at low speed. plus the e fan pushes the hot air to the spring on the fan clutch when sitting in traffic jams and helps trigger the thing more often
Adding a variable orifice valve will regulate the head pressures even more.

If you already have an e fan, then you have problems.

 

[MIDNIGHT RIDER]

I bet your fan clutch probably has quite a few miles on it and doesn't pull squat at idle

My own personal tried and true no-nonsense way of curing fan-clutches is to "PIN" them, thus taking the clutch out of the picture and making them direct-drive.

I have never noticed any lack of power or mileage whatsoever on any of the many engines that I have done this to.

It really is reassuring to hear the air-plane-like roar of the cooling air rushing through the radiator at idle.

I am always scavenging the discards around repair-shops for fan-clutches to experiment with.

I have accumulated enough that I now install a pinned clutch in early summer and switch back to the slipping kind in winter.

I put an electric pusher fan rigged to come on with the ac compressor through a standard Bosch relay

The pusher fans are a good idea.

I also wire in a manual-control over-ride switch, such that I can flip a toggle and the fan come on, regardless of whether the A/C is on or not.

Adding a variable orifice valve will regulate the head pressures even more.

Please explain farther.

What does this valve do ??
Where is it at ??
Does it take care of the variable part itself or is this some user-adjustable feature ??
And, what are the advantages of it over whatever I currently have ??


Sorry for all the questions.

 

[RLDSL]

Please explain farther.

What does this valve do ??
Where is it at ??
Does it take care of the variable part itself or is this some user-adjustable feature ??
And, what are the advantages of it over whatever I currently have ??


Sorry for all the questions.

The variable orifice valve instead of a fixed size restriction for the refrigerant to pass through before entering the evaporator, you get this really fancy one that adjusts in size depending on pressure/load conditions. Basically it makes the hole smaller when the pressure gets higher which makes the evaporator get colder and also prevents liquid from finding it's way back to the compressor suction inlet which puts a heck of a load on it ( that clutch dragging and squeeling ) That's the digest version, It was invented by the same guy who invented the original orifice tube setup I'll let him explain it here in detail..3 pages of detail to be forewarned for those who don't have a clue about ac systems

They are some really great little critters. They are available at Advance and Napa and a number of places. they repackage them under factory air and a few other brands. I have the crossover part numbers around here somewhere

 

[ericboutin]

OK, BACK to square one here. Before resorting to all these surgical measures, you live in a hot , humid climate. You have a slushbox so you have even more heat buildup at idle. I bet your fan clutch probably has quite a few miles on it and doesn't pull squat at idle and you don't have an electric fan rigged to your ac.
When head pressure builds up from excess heat at idle the clutch will start to slip. VERY common occourance around here. I put an electric pusher fan rigged to come on with the ac compressor through a standard Bosch relay on everything that rolls around here that doesn't come with factory E fans or you don't have AC in traffic. Trick I learned many years ago working in an AC specialty shop.

When you put a pusher fan on there it drops the head pressure on the compressor DRASTICALLY at idle in traffic ( not to mention cooling other things down a bit ) and it condenses the refrigerant at a decent rate to where you can actually get some decent cooling at low speed. plus the e fan pushes the hot air to the spring on the fan clutch when sitting in traffic jams and helps trigger the thing more often
Adding a variable orifice valve will regulate the head pressures even more.

If you already have an e fan, then you have problems.

Ok just to make sure I understand...you're talking about having an electric fan on the outside of the radiator pushing air through the (I'm no a/c expert so please forgive...the little radiator used for a/c) the a/c condensor I think it's called. And by doing this it helps with cooling at idle...that's sounds like a cool idea "pun intended'. Where exactly did you mount the fan? Now will this help with the squealing issue already or do I need to still replace the clutch? I'm glad to hear you can just replace the clutch as the whole compressor was around $200...cheapest at Advance Auto.

 

[LCAM-01XA]

My own personal tried and true no-nonsense way of curing fan-clutches is to "PIN" them, thus taking the clutch out of the picture and making them direct-drive.

I have never noticed any lack of power or mileage whatsoever on any of the many engines that I have done this to.

It really is reassuring to hear the air-plane-like roar of the cooling air rushing through the radiator at idle.

I am always scavenging the discards around repair-shops for fan-clutches to experiment with.

I have accumulated enough that I now install a pinned clutch in early summer and switch back to the slipping kind in winter.

How do you "pin" the clutches? I tried bolting up two aluminum plates to the fan blade and the water pump, so that when the engine stops the fan don't try to unscrew itself and kill the radiator, but the moment I shut the engine off that fat pig of a fan blade tore those plates right off!!! Next I'm gonna go with steel plates and fatter ones too, plus all the grade-8 hardware of course, that oughta take care of it all.

 

[MIDNIGHT RIDER]

How do you "pin" the clutches?

With the clutch laying on the bench, I find three or four equally spaced surfaces that have enough meat to drill and tap.

The exact location will vary, as I have seen all manner of configurations for clutch-housings that fit the same engine.

I drill/tap holes for 5/16 bolts.

I clean everything good with paint-thinner, then LOCTITE bolts into the holes, such that the tightened bolts have pushed the internals of the clutch together, thus locking things up.

On some vehicles, I have actually drilled plumb through and simply installed a bolt/nut through the hole.


If your clutch is usable, I recommend you get ahold of some junkers to play with; that way, any failed lessons are free; and, lay the good clutch under the seat for just in case.


I am sure there are some applications for these engines that used a plain old-timey solid fan-hub; finding one of these would be ideal.

The clutches on my wife's truck and my truck are pinned and I wouldn't hesitate to pin another; I have done many over the years.