115 240D york failure (?)

[stei7766]

Hello all,

This is my first time actually posting to the forum, but I have been lurking around for a while. After searching for possible solutions to my problem, I finally decided to take a chance and post.

Here we go:

I own a 1974 240D automatic (115kmi) which was converted to r134a by the PO about four years ago. I don't have the specifics, only the r134 fittings and a $75 receipt for "conversion" and "freon." So for all I know the mechanic simply put the fittings on, drained the r12 and recharged with r134. Regardless, the system worked rather well up until several months ago when I switched it off before accelerating to freeway speed (those 63 horses need all the help they can get) and upon switching it on again I noticed that there was no noticeable drop in engine power.

Well, after troubleshooting I came to the conclusion that the compressor had failed. Removal of the compressor confirmed this as the reed valves (the thin ones) had decided to disentigrate (sp.) and chew the crap out of the york's pistons and cylinder walls. As such the compressor was simply chugging away but not really compressing anything.

I ordered a rebuilt york from ebay (a fellow named a9star9x, who had very high feedback, but I was prepared to get burnt) for $115 w/clutch. Installing the new compressor was a royal pita, neither I nor the service manual seemed to know how to remove the big mongo bracket without draining all the coolant. Well the compressor was replaced, along with the high side manifold hose (broke the %$@# fitting off while getting that huge bracket/compressor back on).

Today I just returned from the ac shop which flushed, replaced receiver/drier, expansion valve and recharged (with r134, r12 is 60 bucks a pound). According to him, while road testing it cooled (albeit marginally) but slowly decayed to no cooling at all. He then checked the pressure and found the following pressures:

idle: 100-110 psi on BOTH high and low side
~3k rpm: 65 psi low side/140 psi high side

Which is not good.
He tried switching the new expansion valve with the old one, just to check (they don't fail THAT often from what I've read and from what the tech told me).

Just as an aside, the clutch works fine and everything activates when it should and the system holds a charge (never needed topping off for the ~3 years that I had working ac).

So, the mechanic thinks I have a bum compressor, which I'm inclined to agree with, and my questions are:

Does this indeed sound like a bad compressor? And if so, can I replace it with the damn bracket still on the engine?
Should I go for a new compressor, like from adsitco (because so far I'm not too confident in rebuilds)?
Or maybe do that sanden conversion I've heard about?
If it's not a compressor, that what could it be? I'm ready to tear my hair out ($500 later and still no ac).
And just to satisfy my curosity, what could have cause the original compressor to fail, as it's my understanding that yorks don't worry about lubrication in the system, as they're internally lubricated. It WAS a 30yr old compressor, so I'm just guessing that it was old.

Sorry for the novel, but I just wanted to make sure everyone had enough information to work with.

Thank you all for your help,
Ben Stein