71 Air Condition questions.

[Michael G.]

I'm in need of some advise on replacing items in my AC system. I DO NOT know much when it comes to AC systems, especially the expansion valve and POA. I want to get my system up and running but don't know what to do with those two valves. I have seen them for sale (NOS) and would gladly pay the ridiculous prices for them if it is the way to go. Does a 40 year old NOS POA valve still retain the quality of a new valve? Is my original servicable? Do these valves go bad?. I'm reluctant to charge the system before I have clean, repaired, or replaced anything I can or should prior. Not being able to check the operation of these two valve without charging has led me to ask for some advise. Thanks, Mike

[Patrick H.]

Re: 71 Air Condition questions.

I'd just send your parts here for restoration:

http://www.classicautoair.com/

There was a second popular AC restoration place in TX but I can't currently recall the name.

My local mechanic (who I've known 30+ years) told me I'm best off with a new or rebuilt/restored valve as if the original has been sitting open to atmosphere for several years I'd be best off having it rehabbed before spending the $ on hooking up the system. Someday I'll get around to that on Dad's 72.

Patrick

[Michael G.]

Re: 71 Air Condition questions.

Very sound advice Patrick, thank you.

[Jim T.]

Re: 71 Air Condition questions.

I'm in need of some advise on replacing items in my AC system. I DO NOT know much when it comes to AC systems, especially the expansion valve and POA. I want to get my system up and running but don't know what to do with those two valves. I have seen them for sale (NOS) and would gladly pay the ridiculous prices for them if it is the way to go. Does a 40 year old NOS POA valve still retain the quality of a new valve? Is my original servicable? Do these valves go bad?. I'm reluctant to charge the system before I have clean, repaired, or replaced anything I can or should prior. Not being able to check the operation of these two valve without charging has led me to ask for some advise. Thanks, Mike

Michael I have kept my 70's factory air conditioning working since it was new. Only real trouble except for the front seal seeping oil was the dryer.
The desiccant in the original dryer made its way from the dryer through the condensor coil and plugged/stopped up the adequate flow through the expansion valve.
This was an easy fix once the problem was discovered by reading my 70's service manual.
The connection to the expansion valve has a steel screen to filter debris. The screen stopped the desiccant.
Removed the screen and replaced it with a new one although the steel screen can be easily cleaned.
Cleaned out the condensor and line to the expansion valve of desiccant from the dryer connection. Installed a new dryer.
Had a shop pull vacuum on the air conditioning system and refill with R12.
Replacing the dryer would be a start to check out your system and it is easy to replace. If yours still has the sight glass in the top of the dryer, it could be the original unit. I don't think the replacement dryers today have the sight glass feature.

[Bob D.]

Re: 71 Air Condition questions.

Old Air Products in Ft Worth restored my system in my '71 for me several years ago. They did an excellent job. They even rebuilt the compressor and did not mess up the original label on it. Their web address is: http://www.oldairproducts.com/catalog/index.php

[Larry M.]

Re: 71 Air Condition questions.

If you have the original POA and Expansion valves, I would send them to one of the two vintage AC repair places mentioned. They can be tested and repaired if needed. Classic Auto Air in Florida does the POA valve repairs, and may be a better choice for you at this time. Both places are excellent.

You can also test these at home, but it requires building some test equipment, and most folks don't want to bother doing this.

Be sure to get your receiver/drier rebuilt, or buy a new one to install when you evacuate and charge the system. This is IMPORTANT. Also be sure to purchase and install the correct oil for the refrigerant that you will be using.

If you are using 134a (not recommended by me....I prefer R12) you can have the POA valve re-calibrated for this change, and you should also be sure to install the HNBR (light green color) o-rings.

If the POA valve is truly NOS and has been capped/sealed in its box all this time, it should be okay to use. Remove the caps and look inside the valve, it should be VERY CLEAN and no rust of any kind. I have one still in the box, and would not be hesitant to use it if I needed it for my car.

Do a search in the archives under "Air Conditioning" or something similar to get much more info.

Larry

EDIT: Expansion valves have inlet screens. They can be replaced or cleaned and re-used. Be sure your valve has one before installing it in your system. The POA valve does not have any replaceable screen....so nothing special here, except to make sure the POA valve still works. Classic Auto Air can handle this.

[Michael G.]

Re: 71 Air Condition questions.

Awesome advice, as usual. I'm sticking to the R-12 Larry. Very grateful to all for the positive direction. Thanks. Mike

[Randy C.]

Re: 71 Air Condition questions.

My compressor and dryer went to Old Air Products in Ft. Worth as well. Same story - great job and they didn't even mess up the original label on the compressor. Very happy with their work. This all happened in 2003 and I went to R134 and it still works great.

Randy C.