LSH77VETTE

I am contemplating buying a new AC Compressor for my 77 because my current one is leaking oil from the pulley shaft and slinging oil on the hood liner. If I do, would like to convert over to the R134 Freon. Does anyone have any suggestions on where is best place to buy a new compressor that can be used with the R134 and is there anything else in the system I would need to replace other than the compressor in order to be able to use the R134 ?

thanks

Easy Mike

You can get a remanufactured R4 at almost all the generic auto parts places. Any automotive AC shop can convert your system to R134.

Keep in mind it's against the law to vent R12 into the atmosphere, so the AC shop will need to evacuate your system before you unbolt the compressor.

REELAV8R

I've seen compressors do this when the system is empty and then seal up with a charge. Is yours empty? If it is I guess you'd better turn report it to the EPA.

LSH77VETTE

LOL..........I have had to recharge it every spring but it still leaks as mentioned. Just getting tired of dealing with having to recharge every year and especially the leak slinging oil around in my engine bay.

jnealg

The compressor is not going to care which its pumping. if yours is leaking and you want to replce it I would suggest a US made Sanden with the appropriate pulleys.
You'll need to change the Schrader valves and make sure to put an appropriate sticker on it to alert others of the change.
The trick is balancing the charge, usually 80% of the R12 charge is close.
You will want to switch to a cycling system if its not already. that year is right in the middle of when the manf's were switching over to a cycling system rather than running the compressor all the time. this is done with the correct valve/sensor.

This is from my techs. I just own the shop. I'm not near as smart as they are.

LSH77VETTE

Thanks for the info. I am not sure if my current system is a cycling one or not. Is there any way to tell by looking?

LSH77VETTE

So if I buy a new compressor and convert over to 134, is there anything else I need to change such as a new evap/condenser?

Rotonda

Before going any further, you need to determine whether your 77 is equipped with a VIR system or a modern an orifice system. Early 77's had a VIR, late changed to the orifice system. (My 77 was built in late February 1977 and had a VIR)

The reason this is important is that to convert to R134a, you need to clean the entire system of the lubricant used with the original R12 refrigerant. As part of this cleaning, you replace the system drier/receiver - a relatively easy and inexpensive task on an orifice system and a more difficult and expensive task with a VIR, because the drier is integral with the Valve In Receiver.

Also, the hoses from your R4 compressor will not adapt to a Sanden, and you will have to have new hoses made by your AC shop. AND finally, the Sanden will require new mounting brackets (Available from Allen Grove and many other suppliers)

Other fiddley bits are cleaning out the decades of accumulated crap that has found its way into your evaporator housing (It's amazing what increased air flow will do to improve your AC), and replace your current condenser with a multipath one designed to shed heat from R134a.

Some people on the Forum will certainly tell you that none of the above is necessary (except the new mounting brackets and the new hoses), giving their experiences. I'm sure it worked for them and met their expectations. However, it is not what is recommended for good cooling and system longevity.

4SPDL81

R12 is the more efficient of the two freons...even including the fact that R12 is harder to find and more expensive...Good luck!

Street Rat

I'd put the Sanden compressor upgrade on it. Available here...

http://www.classicautoair.com/GM_OEM...ompressor.html

jnealg

you will need new schrader valves. they will be on the new hoses most likely.