Clutch Field Assembly Question

[jforest1]

First post.

New to car mechanics.

New to my 73 'Cuda 340, about 2 months old for me.

I believe I have a bad clutch bearing on my RV2 compressor.

In inspecting the compressor, I dove into the clutch assembly.  I noticed the outer circumference of the clutch field assembly appeared to be covered in some sort of rubber/plastic layer about 1/8-1/4" thick. I initially thought this might be causing a problem because this layer seems to scrap on the inside circumference of the pulley assembly inside which it fits.

I have no idea what this is SUPPOSED to look like, so my question is, is the clutch field assembly supposed to just be a metal piece with a lead wire and what looks like rubber/plastic/whatever is actually just gunk compressed over the years?

JF

[ShelbyDogg]

it sounds like gunk like you said. The clutch rides real close to the pulley inside.  Here is a pic

[jforest1]

Thanks ShelbyDogg.  That is definitely cleaner than mine! 
Perhaps its not the bearing after all...I'll have another go at it with the degreaser and scraper and see if I can't bring back that original shine. 


JF

[ShelbyDogg]

There is a seal in the middle, around the shaft. Yours has to have been leaking to pick up that much dirt. I have 3 of those on my e-bodies and all use the RV2 compressor. You can get a rebuilt one at Oreilly's for a little over $100. They do draw lots of HP though. If I were you I would try to install a newer rotary compressor for less HP draw. That is if you don't care about the original look.

[jforest1]

Yeah, I was thinking the same thing.  Only thing holding me back was that if it were just the clutch that was the issue, I'd be able to avoid dropping some coin.  Previous owner called and said the compressor had never worked even before the pulley seized up, so I guess its time to start shopping.

So my challenge is just to get to a working state (without knowing that that looks like), and I'm looking for the surest way to get there.  I'm not so concerned about performance, as mentioned, I'll gain ~10HP just from replacing the RV2, and I'm happy with that.  I'm also not so concerned with the cost, if the end result is working AC (I live in GA).

Speak to me like I'm a total newb (because I am), what do you guys recommend?  Just nosing around, I see a Sanden compressor bracket on YearOne...it looks like if I'm going to modernize the compressor everything moves up to R-134A components.  Is that correct?  Just need a little pointing in the right direction to a proven system.

JF

[Supercuda]

If you are looking to modernize your A/C, the Sanden compressor and a switch to R-134a is in order. Have the conversion professionally done, to include proper hoses and seals, and the proper flush of old refrigerant and oil. If you are looking for an original look, get the remanufactured RV-2 and stick with the expensive but efficient R-12. The clutch coil is wires in epoxy; the pulley bearing probably seized, and the cocked pulley wiped out your clutch coil. Replace both if the system holds refrigerant, and enjoy the cold air.

[jforest1]

The coating does seem like more of an epoxy than compressed gunk.

Alright, sounds like I have a little troubleshooting to do then to see if the compressor holds refrigerant.  If it does or if the leak is an easy fix, I'll go the restoration route.

If I get deep in the weeds, I'm inclined to go the modernization route.  Did I mention my heater doesn't work either?  Seems like something like this might be more appropriate?
http://www.yearone.com/serverfiles/fbshopmain2.asp?pid=944C-974073-EDU&c=0&e=0&hid=126DO16358&cat=1&trk=

JF

[ShelbyDogg]

IF the compressor is not locked up, you should be able to turn the clutch  with your hand. 

[jforest1]

Lead wire disconnected, I get almost a full revolution out of the clutch (takes some forcing).  But it distinctively stops at a point.  Left or right, I can't get a full turn out of it.

The conical part of the pulley where the compressor crankshaft goes--it's cracked along the strip where the key lives.

So not officially checking the compressor the a gauge or anything, but the maintenance discharge line does expel gas upon pressing on the nozzle.  Should I take this to mean that there isn't a leak in the system?

JF

[ShelbyDogg]

Should be able to rotate it around and around till you feel like stopping. Sounds like yours threw a rod. Trade it in for a rebuilt one at the auto parts store. Shop around for the cheapest one. Some of those places think those are in high demand, but they aren't so don't pay too much for one. ($125 to $150 or less)     Still cheaper than a $1300 Vintage air conversion.

[jforest1]

Alright, so here's the fun:

The epoxy layer around the clutch field assembly:



First question:
1.  If the purpose of the clutch field assembly is to engage the clutch magnetically, I suppose this epoxy layer is to insulate the clutch field assembly from grounding prematurely?

2.  if the compressor clutch is NOT engaged (no current to the clutch field assembly), and the bearing the pulley was NOT siezed, it should spin freely and with very little force, because it wouldn't actually be spinning the crankshaft of the compressor, just rolling on the pulley's bearing?  If it were engaged, it would take some force to spin because it would be turning over the compressor, but would spin, yes?

And after the clutch seized:




And the crankshaft of the compressor:



Back to my reasoning:
3.  If #1 and #2 were true:
3a. it doesn't appear as if the clutch was disengaging when disconnected from the battery because i was turning the pulley while it was disconnected.
3b.  more importantly, it looks as if ShelbyDogg's take that its the compressor's fault is inline with the photos, since the crankshaft quite clearly was not turning over.

Am I reading my maintenance manual and these photos correctly?


JF

[ShelbyDogg]

1.Your clutch coil overheated, then expanded the windings till they hit the pulley.  Bad windings, needs to be replaced.
2.When the coils in engaged, it magnetically pulls the outer most "clutch" to the pulley making the shaft spin with the pulley like you thought.
3. Your bearing is probably locked up if the pulley doesn't spin freely when installed on the compressor, without the clutch installed.

Looks like you need all 3 parts.