HVAC problems

[Cbumpus9398]

My 1972 f-100 with v-8 360 has the original under dash unit with original compressor pump. I have removed the under dash part to repair the heater core. Before I put back together, I checked the evaporator for leaks at a professional shop, replaced the compressor switch and reinstalled. Finally have good heat. I waited to service a/c until this weekend. The compressor clutch is engaging. I evacuated the system. Checked for leaks and there appears to be a leak. The evacuated pump bleeds within a few minutes. I converted the ports to fit 134a then I decided to introduce a can of Red Angel stop leak (recommended by my professional). My compressor labels what side is suction(low side) and discharge(high side). I connected the can to the low side and as I opened the valve, the can line blew off, I think under the pressure from the can. The compressor appears to have no suction. My first thought maybe the conversion connections to this old compressor. As you know they have valves in the low side, I wonder if they are not opening, so I removed the valve, didn't appear to help. Any help on how to test the compressor? Give me any thoughts, thanks. Charlie:help:

[tqwrench]

There are two valves on the compressor (roto-lock) that need set to the mid position before trying to run the system. They are each on the inlet/outlet and have dust caps on them that unscrew. Take the caps off 1st.

Then, the best way to set the valves is with a 1/4" wrench or square socket, run them in, lightly seat them, then back them out all the way while counting the total number of turns before it lightly seats in the other direction. Say for example it's a total of 10 turns. Then run it back in 5 turns. Now it's in operation mode. They're there to isolate either the system or the compressor in case you need to make a repair.

[68RGR]

I know this is an old question. However, I ran across this info and thought it might be useful:

http://www.emersonclimate.com/en-us/Bra ... Cards.aspx

See Tip Number 4 which thoroughly explains these valves.

[Rockstar922]

I just bought a 72 and it has heater issues as well. How in the heck do you even remove the stock HVAC unit?

It looks to me like the brace bolt to the bottom of dash just right of the steering column inside, and maybe 2 bolts on the outside of the firewall?

Is this correct? Every other screw or bolt I've seen is to separate the housing & goes backwards.

Thanks.