A/C Charging Question

[TJ Hopland]

The clutch on an A-6 is keyed on the shaft. 

I thought the later stuff was too?   Maybe I am remembering wrong?   I only replaced a couple and in each case it turned out to be a complete waste of time and money because the compressor ended up completely failing shortly after anyway.  Guessing in my cases the compressors were on their way out to begin with and that is what took out the clutches. 

[Scot Minesinger]

To me it is so not worth it replacing just clutch because it is some work and then after it is done, you are at risk to also replace the compressor.  Then what do you do, find a clutch-less compressor (have not see one) and make the switch?

It is understood that the compressor does not engage when battery voltage (including ground) is applied to clutch. My recommendation is replace clutch and compressor, plus dryer, hoses and O rings.  Then you are good for another four decades. 

It is a good idea to pull fan (easy to do) and stick a snake camera in there to examine evap making sure there are no rats nests in there.  Also you can remove sensor or evap casing rubber drain tube and look from those places too.  If your rubber drain is missing that could be bad because rodents can get in there and make a nest.  I have replaced evaps due to rodent infestation.

["Cadillac Kid" Greg Surfas 15364]

Scott (M),
Scott (F) has a system that is leak free, partially charged and nearly ready for operation.  If the clutch coil is bad it is a matter of one bolt and two snap rings to remove the clutch, the pulley and the clutch coil. If you noticed new A-6 compressors are not being built and the rebuilt ones are offered with or (in most cases) without the clutch.  Clutch plates seem to be readily available as are clutch pulleys although they are getting pricey.  The point of this is that we are leaving the day when replacing the comkpressor with a rebuilt one is the easier cheapest way to solve the problem.  I have over 30 "cores" that for one reason or another I kept, and I look at them as my future replacement supply. Although it takes a couple of special tools to correctly remove and replace the clutch plate and safely remove the pulley, the cost is more than justified in one or two usages. I once thought clutch coils were indestructible, but after 35-50 years of operat6ion they too fail.
Scott (F) still waiting to hear back on exactly what moves and what does not when power is applied to the clutch coil contacts.  A picture would be worth many thousand words.
Greg Surfas

[TJ Hopland]

It almost sounds like he must have some sort of shim or disc in there.   Did those have such a piece?  I don't remember anything loose in there but its been a while since I had one of those apart. 

I have also heard not so good thing about the typical rebuilt A6 these days so with that in mind it may be worth a shot to replace the clutch if you are fairly certain that is the only issue.   Since this car has apparently not been in your care very long I don't know that I would trust the previous owner saying it worked last season unless you knew them fairly well.   My last car came with the same story including that it was R12 but looking at the amount of oil around the pulley and clutch found that hard to believe.  By the time I got around trying to test it there was not enough pressure in the system to run the tester so I gambled on my last can of R12 which had oil in it.   Ran for a couple weeks before it sized up so something was apparently amiss.

A couple things I am curious about but didn't want to ask initially but since its not looking like a simple quick fix maybe it would be good info and help figure out what happened here.   I'm just starting to get the feeling we are missing a piece of the puzzle. 

First thing is how did the system go from working fine last season to being vacuumed down?  Typically if they just leaked down a little over the winter it does not take more than just a 'top off' of the charge to get em working again.  If it lost the complete charge over the winter seems like there is likely more than a typical leaking ceramic seal going on.   

Second question is do you know for sure it was R12?   The stuff has been harder (expensive) to come by for almost 20 years now so its getting less and less likely that you are going to find a system that is still running on it especially something that is seasonally driven since they seem to be more prone to leaks in the off season. 

Last thought is are you sure this is an A6?  I don't know your level of knowledge but if this is not an A6 that could explain why the clutch is not making sense to us.   I just saw a tractor that had a direct replacement for an A6 compressor that had a really strange looking clutch on it.  I didn't look that close at it but it did look a lot different than what I am used to seeing. 

[Scot Minesinger]

Yes, agreed A-6 rebuilds are not that great.

Greg, I hear you on clutch bad/leak free system/cost of R-12 and etc.

All, I tend to gravitate towards replace old parts with new/re-built, but the quality is often terrible (A-6 compressor).  I rebuild my own hoses now, so this is a fast, reliable and inexpensive way to go for me.

If you remove the R-12 charge, I endorse converting to r134, but many do not due to 20% capacity reduction and other considerations.

You have all our advice, keep us posted.

Most of all we wish you success!

[CadillacFlashback]

Thanks for everyone's input.  I will post some pictures when I get the chance to tinker with this again.

Scott

[chrisntam]

I just went through my a/c system on my '70 Deville.   I replaced the evap core ($250), got a rebuilt a6 compressor ($250) and all new O-rings ($10) from Old Air Products in Fort Worth, TX  I bought a replacement expansion valve ($20) from Rock Auto, had to get my POA valve rebuilt ($225) by a place in Florida (don't recall the name), pressure tested my condenser ($10) and flushed it out, re-used the hoses and flushed them out.  I went back with R-12 as these systems are meant for this refrigerant.  I could have gone with R134, but I didn't because I wanted my system to work as it was designed (compressor runs constantly and doesn't cycle).  I posted here for suggestions as well and decided to use R-12. I paid a local shop ($225) to assemble the valves, hoses, pull a vacuum on it, charged it up and check for leaks with their sniffer.  I provided the Freon (had it for a long time).  So all together, I have about $1000 in the a/c system, which looking back, is a lot of cabbage.

No leaks (for now!), cold a/c! and I'm good to go for a long time (I hope and keeping my fingers crossed!).  As a side note, the old evap core was pretty dirty and nearly plugged up with dirt and debris.  Too bad we can't figure a way we can add a filter to the incoming air.......Maybe Scot has figured out a way??

[Scot Minesinger]

That is great that your system is working well.  I have only seen one dirty evap out of a dozen or so changed in the last year or two and it was due to rodent infestation.  Our area of the Country is not dusty and has clay soil, so air born dirt is not common.  Air filters require low velocity airflow which requires a large surface area.  We just do not have that in our cars and a filter is a difficult modification that probably will not do much good.

To keep your system rodent free there is a rubber drain hose about 1.5 inch dia. that terminates to a slit.  It lets condensate water out and keeps rodents from getting in.  Make sure that is in place.  If not it is like under $10 at USA Parts.  To see it easily raise passenger front corner of car onto jack stand and it is at bottom of evap casing. 

If you have trouble finding it, wait for a humid day and run a/c for half hour, while car is still running raise passenger corner on jack stand and shut off car.  Immediately get under and see where condensate drips out.

["Cadillac Kid" Greg Surfas 15364]

Awfull small rodent that gets through that 1/2 inch drain line.  More likely they have chewed through the mesh on the cowel intake ande have a lot more "home on the range"
Greg Surfas

[Glen]

Glen,
The clutch on an A-6 is keyed on the shaft. 
Greg Surfas

Agreed Greg, the coil is fixed behind the pulley; the pulley rotates freely when the coil is not energized; the clutch plate is attached to the compressor plate with a nut on the end of the shaft and is keyed to the shaft.  When the coil is energized the pulley is magnetized and the clutch plate is pulled into contact with the pulley and the pulley then drives the shaft.   

But if the clearance between the pulley and the clutch plate is too large the clutch will not have enough pressure on the pulley to drive the shaft. 

That is what happened on the 88 Chevy.  The nut was loose and the clutch plate moved away from the pulley enough it was intermittently driving the shaft of the compressor. I tightened the nut and all was well with the A/C.   

[Scot Minesinger]

The drain hole is one and a half inches in diameter, not 1/2" (sorry about typo).  In referring to the coil on rodent infestation, it is the evaporator refrigerant to air heat exchanger up at the fire wall that the blower discharges into.  It is not the electric coil on the clutch, which it is agreed not a rodent target.

Here is a picture of the damage after nest was removed from a 1967 Cadillac DeVille evap casing photographed in spring of 2013 or so.  Next picture is of the drain tube.  With next in there, air flow was reduced to near nothing.  On this climate control restore, the only two things I did not replace were the condenser and the blower motor (did replace blower wheel).

I worked on this car restoring climate control, portions of exhaust, cosmetic work under the hood and chassis, dash work, and replacing body to frame bushings during winter-spring 2013.  Then it won GN Primary 22 in Boston 2013.  How cool is that? - I can say that I'm a prize winning mechanic.  I worked on this car too much and let mine go so it did not do well in Boston, but earned a 3rd in NY at GN P22 category.

["Cadillac Kid" Greg Surfas 15364]

Glen,
Mis interpreted your post regarding.  Although you can pull the clutch plate in with the nut, the proper way is with the clutch installation tool.  Using that tool pulls the plate in to the (I use) 0.025") clearance that works best (for me). Using the nut which is just intended to keep everything together, puts the stress on the nut which often (apparently in your case) leads to the clutch plate loosening up.  Although it has been quite a while since I saw one installed, OE compressors used a final snap ring outboard of the nut just as an additional safety.
Greg Surfas

[CadillacFlashback]

OK guys here's a picture.  Excuse the shadow. 

You'll notice I have marked in red the disc in between the thick black clutch plate on the front and the pulley the belts ride in. 

When the A/C is off, the belt pulley turns but neither the red-marked disc or the thick black clutch disc spin. 

When the A/C is turned on, the red-marked disc begins to turn with the belt pulley.  The black clutch disc remains stationary.

If this helps anyone with any ideas, let me know.  At this point I am leaning towards full compressor/clutch replacement.

Thanks

[TJ Hopland]

Its been a long time since I worked on one of those and don't have any handy to look at but I think the 'red' part is supposed to be attached to the 'blue' part.   I believe that plate is held on the hub part with 3 rivets.

["Cadillac Kid" Greg Surfas 15364]

Scott,
It looks like you have a bad clutch disc.  There are rivits that attach the two parts and if they shear, you get exactly what you are reporting.
The clutch disc can be replacede, but again you really need the proper tool.  They are available at most auto parts stores, and in fact some of the stores might even loan you the tools.
Best way as I said before is to take the mounting brackets loose and rotate the compressor nose "up" so you can work on it.  With the tool R and R takes about 5 minutes.
Greg Surfas

[CadillacFlashback]

Scott,
It looks like you have a bad clutch disc.  There are rivits that attach the two parts and if they shear, you get exactly what you are reporting.
The clutch disc can be replacede, but again you really need the proper tool.  They are available at most auto parts stores, and in fact some of the stores might even loan you the tools.
Best way as I said before is to take the mounting brackets loose and rotate the compressor nose "up" so you can work on it.  With the tool R and R takes about 5 minutes.
Greg Surfas

When you say the "clutch disc" are you talking about the red part and the blue part in my picture?

[chrisntam]

Here's a pic of the evap core I pulled out..........

[chrisntam]

Here's a pic of my A6, you'll have to zoom in to see the clutch part of the compressor.  I think the black part and red part are supposed to be connected............

[CadillacFlashback]

Here's a pic of my A6, you'll have to zoom in to see the clutch part of the compressor.  I think the black part and red part are supposed to be connected............

The weird thing is they seem to be connected.  The pic below is a close-up of rivets that seem to connect them.  With the engine off, I can turn the front with my hand and the whole thing turns together.  But with engine running and AC on, they do not.  Seems awfully strange.

[Scot Minesinger]

Chris,

Nice looking engine bay.  looks like you have not started it up yet at the time of the picture.  My Hirsch blue paint burned off the heads at exhaust connections in about ten minutes after I started it.  Did yours hold up?, and if so how did you make it happen?

Thanks,

Scot