I have an eighty five el camino, and I replaced the ac compressor with a later model compressor and serpentine system. I replaced the accumulator and orifice filter. I charged the system with forty two ounces of 134. I'm not sure how much freon it needs, but my gauges read around thirty five on the low side and one fifty on the high side. It does not cool well, and the compressor short cycles. I'm not sure where to go from here, I'm thinking I have too much freon, but it does not cool well. Maybe I don't have enough. Thanks merc

Way to much takes about 2 1/2 Cans Of 134 also depends on the outside air temp hard to charge in cooler weather and low humidity

Also when you opened up the system didyou slush it out Brake klen works well for my blow out all the hoses and and make sure to pull a Vacume for about a hour than let it set under a vacume for about 30 mint or so and watch your guages:beer:

I guess I need to do it over, I did pull a vacuum for at least an hour and it held. System flushed. Also, I have another question. It has a after market inline orifice filter on the high pressure side going to the evaporator core. Which way is the filter supposed to go? Should it be facing the condenser or the evaporator core?

When changing from R12 to R134, you will likely need to adjust the low pressure switch, located in the accumulator. If you pull the connector off, you will find a small screw inside the switch. Can't rememberr which way to turn, but I think it is clockwise. Took maybe 1/4 to 1/2 turn to get the compressor to cycle longer.

When I did mine, IIRC the pressures were showing about 22 on the low side, and 225-250 on the high. This was with OAT aroud 100. And IIRC, it took almost 48 oz to get to those pressures. AC guy wanted to put more in, but I told him that was more than enough!

Try www.autoacforum.com (http://www.autoacforum.com) for info. Looks like the high side pressure is low for R134.
I used a 2000 Blazer condenser on my 86 Elky, but had to change the line fittings and make spacers . The Blazer condenser is the correct width, but about 2" shorter. It is a paralell flow instead of a serpentine flow condenser. There are lots of them in the salvage yards.

the filter should go upstream of the orfice,,or the condensor side of the orfice...:texas:
42oz sounds high(3.5 cans),,but 150 psi and short cycle sounds like its low...:dontknow:
thanks for reminding me about the switch,, darbysan:beer:

Thanks for the info, I did forget to mention that I have a 94 impala condenser in it, and it has a serpentine system with the compressor on the passenger side, and I did modify the lines to get everything to fit. I will check the low pressure switch tomorrow and post my findings. Also, I forgot to mention that this truck has a 454 in it. I drove it today about a hundred miles, it ran good, the air works but it does not cool enough. It has dual exhaust with two and a half inch pipe, and flowmasters. It is very noisy, I need to do something with the exhaust, or else wear hearing protection. But, it does run GOOD.....Thanks, merc

Okay, I recharged the system with the same amount of freon, pulled a vacuum and let it sit for almost an hour. I adjusted the low pressure switch. oat was 68, low side is 25-30, and the high side is around 175. It pulled down to around 45 degrees, with the doors open and on max ac.