The Texas heat is coming and my girlfriend won't ride in the truck without air. I pulled a vacuum on the system last weekend, but the truck won't take a charge. I think there is a restriction in the system. I replaced the orifice tube, which was stuck because the upper O-ring seal was out of the groove and wedged between the tube and the inner pipe wall. That didn't do the trick, so I ordered new shrader valves, an O-ring kit and the new receiver dryer. Hopefully that will do the trick. I will also blow out the lines with compressed air as I go.

I did jump out the low pressure switch briefly and the compressor clutch was cycling properly. If this doesn't do the trick, the condenser coil is next. The receiver dryer is cheap enough and original equipment, so I might as well replace it and blow out the low pressure line. I may try to blow through the condenser as well.

Pulled a vacuum on both vehicles

Love me some Harbor Freight for this shade tree work

Good vacuum held for one hour. I actually got it down to -30, but didn't get that picture.

134a can attached to low side, compressor will not come on

 

Has to be adequate pressure for the compressor to kick on. Given you are starting with a vacuum, probably take a can or two before the compressor runs......

 

Thanks for the feedback. The problem is that it won't take anything as seen in that picture. The low side will pressure up with the can pressure, but the high side never goes up.

So, the new receiver dryer is in, all new O-rings, blew through everything, no restrictions, pulled a vacuum, been sitting with a vacuum for a good 30 minutes. I am taking a break and then will attempt a charge again.

 

I would suspect the low-side pressure switch is bad then.

 

Well, the cabin is incredibly cool now! Two full cans, 32oz, and the compressor seems to be very happy. I pulled vacuum for an hour to dry the system, then I hooked up the first can. Low side pressured up, high side, nothing. Crap! not again. I was checkin connections and pressed down on the low side fitting from the gauges and Voila! the freon began to flow. I let go and the freon stopped. I pressed back down again and the system resumed charging.

I have had these gauges forever, but haven't used them in probably 15-20 years. I had completely forgotten that these have a built in valve (I assume) that requires the operator to hold down on the fitting. I suppose that is a good idea, but it sure had me baffled.

So, I know that the system is freshly sealed, new orifice tube, new dryer, new freon. I should be good to go!

 

I am not sure I would have ever figgered that one out.

Congrats! Now your girlfriend will ride with you.

 

​​​​​ The fairer sex still has the power to motivate me to great lengths.