I am in the process of an under hood refinish on my 76. The motor and trans are out and going to the rebuilder. The entire suspension is now out and I am putting in all new bushings. So the next thing is the air. I have taken it apart, there was slight pressure in it. I have been careful not to dump the oil out. A friend told me that since I have taken it apart the VIR needs to be repaced. First question what does VIR stand for and what does it do? I looked at these and they run $250??? Wow, I also saw a VIR eliminator, what can this do for me? My friend also said I should upgrade to more modern components... like what, from what years? The system is all there and looks good. Any A/C gurus that can shed some light on this? Would be much appriciated since I am not too familiar with A/C.

Thanks,

Mike

 

are you wanting to stay original or upgrade?

 

If you want the configuration of your car to remain "original", just replace any parts that are 'suspect' and rebuild it the same. Modern components are more efficient...they run only as needed, so some fuel is saved; but they are costly to swap out, trouble to remount properly to the car, and the new refrigerant will not provide the same amount of cooling that R-12 can do.

I recommend that you search out and contact a well-known automotive A/C service person and pose your concerns and questions. He/she can give you all the pros and cons and you can make the final choice of what to do.

Lastly, the original system is very reliable, if it is properly serviced and maintained. If you have the components checked out and find them to be A-OK, going back together and filling with R-12 makes the most sense to me.

 

Mike,

VIR stands for "valve in reciever". There's an expansion valve in the top section, and a desicant drier bag in the bottom cannister portion. You don't need to replace the entire unit unless the valve is bad. Not completely sure, but I don't know if an expansion valve can really go bad. It's just an angle valve with a small orifice. As long as the orifice is in it, and it's clean, it should be fine. You can buy a rebuild kit for the VIR that has the new desicant bag and oring.

I have went through the AC systems on my 71 and 76 vettes and recharged them with R12. They both work really well, and that would be my recommendation to you, fix the original system, they work great.

Hardest part is taking the AC box out of the car but it was needed badly. Both my cars had leaves, acorns, etc in the AC box so air could only partially flow across the evaporator core. 71 also had a couple of cracks in it I repaired with fiberglass. Also the seals were in bad shape and letting hot air from the heater core flow into the vents when it wasn't supposed to.

My advice:
Remove AC box, cleanout, put new seals
Flush all components really good.
New desicant bag in VIR.
Test valves (look on ACForum for articles how to do it).
New hoses and orings
Fill with Oil, pull vacuum, and fill with R12

Listing it that short makes it seem easy.

Good luck.

Roger

 

Thanks Roger, that sounds much better, I have the engine compartment "bare nekid" right now so its time to start re assembly. I will look for a VIR rebuild kit. Once I install these parts do I have to keep the VIR sealed untill I assemble the entire system? This process will take a few weeks with my time schedule.

Mike

 

Mike

Yes, you need to keep the vir seales so the desiccant doesn't absorb too much moisture from the atmosphere.

I would take it apart and clean it, but not reassemble it until you are ready to install it. It's an easy part to work with. Only takes a few minutes to assemble.

Roger