I have read several topics on the different opinions on converting these old trucks to r134a. A year ago I converted my system on a limited budget. I replaced the dryer, and flushed the entire system. I tore apart the compressor, and verified no structural issues, and cleaned it thoroughly. I then put the proper amount of ester oil in, and pulled a vacuum allowing the system to sit overnight to make sure there were no leaks. I then proceeded to charge the system using straight 134a with no additives. The air conditioner does work ok, but being in the Texas heat ok just doesn't cut it. I've since decided to replace the condenser with a parallel unit, and am thinking about converting over to a sanden compressor. Now, I know some of you are going to say that I should certify online and buy the r12 and go stock, but my main concern is that I will still have the old two cylinder compressor that shakes rattles and rolls. Quite frankly my old 351m just doesn't need the extra drag on it. From what I've read, the sanden compressor runs with much less drag, and quite a bit smoother. My question is this: Has anybody here done this, and what issues did you have to face in order to do this conversion? I know there is a conversion plate available, but has anybody fabbed their own? What about the hose fittings? I'd like to hear some opinions on whether or not the compressor and condenser change will help me out at all. Sorry for the long post, but I just wanted to make sure that I got as much information out as possible. Thanks you guys, this site is the best by far.

 

First, my truck's AC was converted to 134a back in 1998. Now, it has a leak in a couple of o-rings, so need to fix that. Go with a Sanden unit. They are hands-down the best quality aftermarket out there. I have put these on early 90's Fords and Chevys and no issues at all. Look at your orifice tube and that will tell you if your old compressor has puked its guts internally. Also, if your condensor is a parallel flow or newer design, it'll be a biotch to flush completely (must remove all mineral oil from your system). The PAG oils that 134a are a hell of a lot more sensitive to moisture than the old mineral oils. In fact, anything that is 'poly-oxy' or glycol or such is hydrophilic.

 

Definitely go with a Sanden. My York was working fine, but I could never get rid of that belt vibration even with over-tightening it, bolting on an additional idler pulley, etc. Put a Sanden in it's place and I've got no belt vibrations at all and it cools well. Looks better too.

 

Go with the Sanden and the biggest parallel condenser you can fit in there and maybe add a electric fan in front of the condenser for those times when you are stuck in traffic. You can find a lot of info here: Automotive Air Conditioning Parts & Equipment - ACKITS.COM
I am also in TX but I still run R12 but plan to convert some day. Good luck and where in TX are you?
Mark

 

There are a few ways. You can piece together a factory AC or dealer installed AC unit from donor trucks.

I am piecing mine together with a dealer installed AC unit. Honestly, I think it was a mistake. I wish I had just started over with one of the ACKITS.com setups. my time is worth around $.25 an hour, and I could have paid for the kit!!