What can I remove?

[tgreese]

The AC on my J20 has never worked, and the naked evaporator has always dangled below the dash. All of the plastic housing is gone from under the dash.

There is a cap with a Schrader valve labeled L on the compressor. If I press on the pin and vent it, nothing comes out. Can I assume that the system is empty? I'd like to remove the evaporator and what looks like an expansion valve and cap tube from under the dash. It's in my way and I won't reuse it.

I may renovate the whole system with a new aftermarket AC unit some day. Not really a priority in this clime.

[Stuka]

I am by no means a knowledgeable A/C person, but to my knowledge the L is the low pressure side. There should be another valve that is the high pressure side and will be marked with an H. The low side not having pressure doesn't always guarantee that the high side is also empty.

[SJTD]

If it has the service ports and valves on the pump then in the normal operating position they are back seated and the service ports are isolated from the system and will have no pressure behind them. That way if they leak the system doesn't loose pressure.

You have to unseat the valves before trying the Schrader valves to check for pressure.

[tgreese]

There are two service ports at the compressor, plus this additional "L" labeled port with a plastic cap and a Schrader valve. The service ports look like what the TSM shows, and have aluminum caps. Hoping to avoid buying some gauges now (had some long ago, "lost" them somehow).

[SJTD]

If they're like what my ole '84 York had, the long aluminum caps covered the service valves. Under them were the square stems.

Nice thing about these old systems is you could run those valves all the way in and isolate the compressor from the rest of the system if you had to change it without loosing the charge. You only lost what was in the pump itself which was mostly gas. After you put the new one in you opened one valve, cracked the other and purged the pump. You didn't have to suck down the whole system. Or if you wanted to be thorough you could hook up the vacuum pump but it was still only sucking on the the compressor. The rest of the system still had the charge.

Anyway, like I said. If you crack one of those valves and press the Schrader you'll know if the system still has gas.

The book should have a picher of the internals of the valve. Mine does. Or search it up.

[Srdayflyer]

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- A d yea the oem valves were designed zo u could svc the compressor, and not loose ur charge.

[Stuka]

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- A d yea the oem valves were designed zo u could svc the compressor, and not loose ur charge.

NO Politics means NO POLITICS. Period.

[tgreese]

To wrap this up -

Looking at the TSM, the valves on the compressor were set to fully open, which blocks the service ports and opens the system and compressor. Moving to the center position (service ports open), I found the system contained nothing but air - no refrigerant left. I then removed the cores in both service valves, put the cores back, and closed off the compressor (valves fully in).

I removed this stuff by disconnecting at the compressor low side and the sight glass.

J20JunkAC.jpg

This left a lot more room under the dash, which is what I was after. This will allow easier ECU mounting, to be shown in another thread. Looks like this was factory air. I blocked the factory grommet in the firewall with a piece of aluminum flashing cut to fit under the grommet.