I have a 1977 300D with an 1981 300D engine. The "77" engine had the york compressor over the alternator, while the "81" engine has the r-4 compressor under the power steering pump which is there now. My question is the following: The line from the drier to expansion valve is still intact, as well as drier to condenser. Would it be ok to just buy the hoses for an 81 and connect compressor to existing condenser and expansion valve?? Basically are they interchangeable?

I don't see why it shouldn't work as long as you stick with the refrigerant it was designed to use back in 81.

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Jim

I asked the earlier question in regards to the a/c system..because trying to do the work myself, basically a weekend warrior. Now just so i can understand, Are the drier, evaporator, and expansion valve, and condenser all the same on both a 77 and 81 300D??? Since I went from the 77 engine to the 81 engine? Since i want to replace the r-4 compressor with a new one, and everything being the same all i would need is the a/c suction hose from behind compressor to the expansion valve. Is that correct? I would also replace the drier and expansion valve

Thanks you

I am not able to envision exactly what you have but you will, in all likelyhood, need the refrigerant hose from the 81 car. Is there any way you can compare the condenser connections between the two cars? This may be another issue. The exp valve should be located in the vicinity of the evaporator. You may be able to stick with the existing expansion valve. There should not be an issue with this arrangment as long as you stick with r12.

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Jim

IMHO your best bet would be to mount the original York compressor on the later model engine. I can't think of anything on the later engine that would prevent this.

I have two 78's and several 80+ models, IF I get some time, I could compare the two side by side. (which is the best way to see if this melding would work)

I don't have the original york compressor. I was also wondering if there would be an electrical problem with the SERVO and climate control unit which are the 77 vertical push button and the side ac on off compressor switch with the r-4 compressor. I will try and post photos of what I have..not my photo here but control unit..

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I am trying to post pics but there are too big to post here. It seems that the condender connections are the same.

posting big pics is easy.
upload them to photobucket.com and copy the img tag link provided to this site.

all compressors I've seen use the same 12V to lock the clutch. I'd bet the control unit would be fine to engage the R4 compressor. (since that same unit powers my 79 with the R4 compressor)