Is there anybody nearby that can help me test my 78 F150 to see if she still holds a/c pressure? I think it's the old R-12 system, not the R134. I can't afford the money to have a shop check it out for me. And I can't afford to buy a set of gauges either. I've got the replacement oil and R12 refrigerant cans. I just need to make sure there are no leaks before I recharge my system.

 

I have a leak detector, and R12 gauges. A reclaimer and vacuum pump would really make it easier, but we dont keep them in our shop for R12 anymore. Are you talking about just hooking up and seeing what it reads or?

 

Yep, I originally just wanted to see if it'll hold pressure. I finally got the blower switch fixed and took the truck to B&M Exhaust in Owasso on Saturday to get the system evacuated and pressure tested. But we couldn't even do that because the service valves were froze solid. I'm in the process of trying to find a set of replacement valves for both the low and high side. I've got 3 cans of R12 equivelant replacement and one can of R12 compressor oil. I have the side puncture charge hoses for the R12 freon, but I don't have a set to get the R12 oil into the system and B&M Exhaust does not have a connector for this can either.

The first hurdle is to get replacement service valves. I'm having a hard time finding them.
Then if it'll evacuate and hold pressure the next hurdle is getting the compressor oil into the system.
The last and easy step would be filling the system with the 3 cans of R12.

 

Ditch the pressure cans of oil, why make it hard. Buy a bottle of R12 oil and poor it into the accumulator, and compressor. Seal system back up and evacuate. Watch and make sure the pump doesnt draw out oil when it sucks it down. never had a problem getting those valves open, myself. Add the oil, change the seals, and hoses if your really into it. Hook up the gauges, evacuate, and charge.

 

Oh, I didn't know the oil came in unpressured bottles. I just might do that. But how much oil should the compressor take?

The valves look like they were abused by the previous owner. This was an old farm truck and when they had the engine off for a rebuild they never messed with recharging the a/c system, so none of the parts were adjusted for a long time. The mechanic couldn't get the service valve to budge, even with a vice grip. So now I've got to find a good used set.

Can I get new seals easily without buying some big ol' kit? The hoses are still in great shape on the outside.

 

Seals are a matter of matching up, no biggie. Oil, a dry compressor on a late model is around 8 oz if its dry. Id replace the accumulator or dryer regardless.

 

BOOOYA! I finally found a place just down the street from where I work that had all the parts and orings that I needed! It is Vincents Auto A/C on 11th St. Between Harvard and Yale. They knew exactly what parts I needed and I got both service valves and a new dryer, all with orings for about $62. Heck of a lot less expensive than Oreilly's! Now all I have to do is get the system evacuated and then I'm tempted to recharge it myself. We'll see. I've never done a/c work on an auto before.

 

I deal with vincents alot, they are a neighbor of mine. Anything weird comes in, I send it to Candy, and let her sort it out. Be careful of doing it yourself if you lack experience. Ive made my fair share of money from people making mistakes. Make sure theres enough oil in the system, etc. Unless a scorcher hot day, high side pressures are goin to run around 250 psi on R12, once it levels out. Low side varies according to evaporator temp, but hot weather liek today, on high speed, youll see 30 psi I bet. If theres not enough air getting thru the condencer, or weak fan clutch or its just hot, you could see 300psi, but thats the highest you better see R12. If you fill it to what the capacity is and pressures are low, chances are you dont have enough oil. Hope this kinda guides you. Good luck!

 

Thanks for the advice. I had my system evacuated and pressure tested at B&M Exhaust in Owasso on Friday afternoon. And she tested fine. The oil level is a tad low.(Should be 1/2" to 3/4" deep in compressor) I had my father-in-law show me how to recharge it with 3 cans of R12 replacement. It works, but she's not super cold. It blows fairly cool air, but not colddddd. I figure that I need another 6oz can of Enviro-Safe R12 replacement. That's the brand we used, but I'm having trouble finding a local distributor/resaler of Enviro-Safe and I'm not sure if it's safe to mix different brands?

 

I use freeze 12. I talked to the guy at vincent's one day and he said that they use it quite a bit. Might check with him about dumping the freeze 12 on top of the enviro safe. I know you can dump it on top of r12. I've even heard of people dumping 134a on top of r 12 and it works ok. I think that all that crap about mixing will ruin your system is just crap. I know that if it were mine, i would try it. The worst thing that can happen is it not work. If you added oil, i hope you dumped the old out and added ester oil. Just my 2cents.