1990 E250 A/C rebuild.
 

Hello everyone! I just joined the forum in hopes of finding some information on rebuilding my A/C in my 1990 E250. I decide to buy new 4 season parts as the ones I will be replacing are 33 years old. Does anyone know where I can find information or articles on such a job. I have googled and YouTubed but it seems that most of what I find are for the 4th generation vans.
Any and all help would be greatly appreciated. Thanks in advance.

Patrick

Not sure if we can be of any help until we know what questions you have.
What is the present condition of the A/C system now?
Do you have a set of manifold gauges , vacuum pump and leak detector to use?

The A/C is not working and I believe has been evacuated from what the previous owner had told me. I think they tried to change it over from R12 to R134a so it could have mixed freon in it. I have purchased a new compressor, accumulator, o-ring kit and what looked like a pointy filter. I have a vacuum pump and a flush kit. My hopes are too replace the pump and while it's apart flush and inspect the system. Replace what needs to be replaced and then nitrogen and vacuum it. I am fairly mechanically inclined and have worked with home HVAC.

If you drained the oil from each component when removed, you should add that amount of the correct oil for 134A to each component when installing.

The molecules of 12 were larger than those of 134 so it was recommended to replace the old hoses with nylon lined new hose to prevent loss of refrigerant..

Some folks did not replace the old hoses and it worked fine, just don't know for how long.
I would think if you flushed the system and purged the nitrogen thru it , it should be OK.
When the previous owner said it was evacuated ,what does that really mean? If there was a component failure ,you need to start from scratch anyway.
If you are familiar with procedures for home A/C they all are similar , just different refrigerant. and oil.
If the system will hold 29 in vacuum (watch the manifold gauges) , it usually has no leaks, but could leak under pressure ,so leak tester is recommended to assure a good job when adding refrigerant. If you evacuate with the vacuum pump for one hour, that usually was acceptable.