What would cause an A/C system not to suck in freon?

[WH23G3G]

I've recently redone an aftermarket A/C system on an import. It was dealer installed in the late 70s early 80s. I redid everything like it was originally setup. I reseal the evaporator box, had the evaporator checked, repaired, and flushed, condenser checked/flushed, new drier, new expansion valve, all new hoses with 134a service fittings installed, an additional filter, and a new compressor. Well when the shop put the fittings in they installed them on the wrong hose, so when I installed them the low side ended up being on the high side and high side on the low side. It still was able to be recharged and it worked for a year, but this spring when I started it up, it wasn't cool. There was a leak at a loose compressor hose fitting. Well now I've swapped the hoses around, vacuumed it down for 35 minutes and went to recharge and it's not taking anything in at all. The compressor does indeed come on when I switch it on, there is no abnormal noises or vibration, it's smooth. When the engine is off and the clutch is turned by hand, it doesn't turn loosely like if the crank was broken. So I'm not convinced it's a bad compressor. There is only a short hiss from each port if you poke the valve. So it's not taking any freon in. You can see what is in the system flowing through the sight glass of the drier. A mechanic told me he would bet the expansion valve is stuck closed. Why would it get stuck closed? When a gauge set is hooked up, it's not showing pressure on high or low and freon won't go in. There isn't anything in the system, just oil. What do I need to check to determine the exact cause? I got a lot of money into, I don't want to lose my compressor if I haven't already.   

[bandit67]

No vacuum.  Seems like either an error of valving when you were attempting to pull a vacuum or a leak some where that did not alllow the system to pull down.  If you have the new type 138 fittings , they can be the devil to work with sometimes. I paid a 100 bucks for a new set of gauges with the new fittings and promply misdiagnosed two problems because of them.  Got a high dollar adapter for my old R 12 gauge and have never had a problem.   I take a drum of 22  [cause its cheaper} and pressurize the system and check for leaks. Finding no leaks, I will pull a vacuum for about 5 minutes. Stop, and watch the gauge, if it creeps back up to normal fairly quick, you still have a leak. If it holds, pull for another 30 minutes , min.  If that holds for at least several minutes, it will suck in at least a can or pound of R 138.  At this point , jump out the pressue switch , and charge up to correct pressure....................J

[WH23G3G]

I've got nothing going on. When I opened up the hoses to change them back to the right places, there was hardly anything coming out of them. There was no residual pressure in the lines at all, so everything must have leaked out of the fitting that was loose. Originally I had the low pressure hose hooked to the high side and the high side to the low side, but it still worked by sending the freon through the service fittings on the compressor and cooled down to 35. But after it sat for the fall and winter, there's nothing going on now. No pressure, can't get any freon to go in. I can see through the sight glass that the oil is moving around. Does that mean it has suction still? One mechanic told me the compressor was probably trashed because I had the hoses hooked up in the wrong place and operated the system while I had them hooked up wrong. He said the reed valve is stuck or something with the reed valves. If there is no freon in the system, and I can't get any in right now, how can I rule out that the expansion valve is bad? Another mechanic told me the expansion valve is the cause, but he says the reason why I'm not getting a high side high pressure is because there isn't any freon in the system. The evaporator box is difficult to access and so is the compressor. I don't really want to remove either if I don't have to. I want to determine what is bad before I start removing everything. How should I go out about this?