AC repair, opinions

[schardein]

I've noticed several AC related questions here lately, and wanted to get some opinions.

 

I have three vehicles I need to repair the AC in.  2001 Silverado, 1991 XJ, 1991 MJ.

 

About 5 years ago, the Chevy was vacuumed down at a shop, held vacuum, was refilled, worked good for a year, then nothing.  R134a

 

The XJ has never worked since I've owned it.  It has been converted to R134a at some point in the past.

 

The MJ has never worked.  Still R12.

 

I just bought a 3cfm vacuum pump and a set of gauges from Harbor Freight.  I also have a CPS scale for weighing the R134a can so I can monitor exactly how much I put in.

 

I intend to get all three working.  I am planning to buy a 30lb can of R134a since I have several vehicles to maintain.

 

My question is on the MJ.  I am thinking of just replacing the compressor, condenser, expansion valve, dryer and lines.  Since I am replacing almost everything, could I buy all the parts for a 94-95 XJ model, and have parts that are already designed for use with R134a?

 

Also, any downsides to not replacing the evaporator?  I really don't feel like completely tearing down the interior if I can avoid it.

 

Once done, I then plan to repair the XJ.  I could use the same approach of replacing everything, but I could also look at the parts removed from the MJ as possible donors, if they are in better shape than the XJ stuff (MJ 150,000 miles, XJ 220,000 miles)

 

I don't have any formal training on AC systems, but I have been doing a lot of reading on it.  Are there any other tools I should look at getting?

 

I know this is a lot, thanks for any comments or opinions.

 

 

[Marine1Texas]

evaporator only needs replacing if it is leaking. no reason to change parts on it. Since you are doing so many vehicles you might as well buy a hose making kit, then you can make your own and not go shopping and hoping to get the right . I am not sure on the newer 95 if the ac stuff is the same. I would think most the same other then maybe the compressor change maybe.

 

hose making cite, would be the clamps, fittings and the hose. all you do is use a good torque drill/wrench to tighten it and seal the clamp down. make sure to get the kit with #6 connectors that is what jeep use and most cars. I would also save some money on the receiver drier and go with a standard universal one. that way in the future it is very easy to find and replace. also they run less then 30 dollars a piece. I buy in bulk, so I get for around 12 dollars a piece. scales for car a/c work, but in the end some compressors are not equal in all always even in the same year. meaning you can be as much as 7oz more on one system then another to get the same cooling power

 

Make sure not to pay no more then 120 total for your 30 pound can. the going rate is 1.89 to 2.23 a pound when you purchase it in bulk.

[schardein]

Thank you for the reply.  I am looking at this for the R134a:

https://www.amazon.com/Johnsens-R-134a-Cylinder-30-lb/dp/B001DKPRRM/ref=sr_1_10?s=automotive&ie=UTF8&qid=1467842626&sr=1-10&keywords=r134a

 

Is this an example of a hose making tool you would recommend?:

https://www.amazon.com/Mastercool-71550-Black-Manual-Crimper/dp/B000WBQ4U2/ref=sr_1_2?s=automotive&ie=UTF8&qid=1467842743&sr=1-2&keywords=ac++hose+kit

[Marine1Texas]

yea both of those are pretty good ones.  your still need some hose and the fittings. they may have a all in one kit. I get fittings by the bulk, if I see a kit I will post up one.