1995 k1500 automatic with 4x4 manual shift. 215,000 miles.

hey guys, I just bought my first truck 2 days ago (not first vehicle) and im jumping straight into my ac system. the compressor is squealing/rattling badly and lots of metal shards came out of it with a magnet held near...completely shot, i know. so, ive ordered a replacment compressor and accumlator, plus a condensor...for good measure while i have the system open.

im mostly a redneck anyway, plus a noob at trucks, so my question is, what else should i be concerned about while doing this job such as:

do i need to seal the threaded connections in some way to prevent leaks or does this mess come with rubber gaskets/seals that are sufficient?
should i put in the UV oil dye stuff to inspect for leaks after doing this major ac overhaul or just trust myself and the products and see if it leaks down over time?
major do's and dont's?
your experience?

thanks in advance

 

I would replace the $3 inline orifice tube/filter while it is open. If you have or borrow (autozone) an a/c vacuum machine and manifold gauges. When all parts connected, before placing freon in, pull a vacuum for 5 minutes, turn off and wait 30 minutes to hold vacuum. It shouldn't move the gauge needle (full vacuum). Then you know you don't have a leak.

 

yep, ive also ordered a vacuum pump and borrowing a set of manifold gauges from a a friend. I'll add the orifice tube to the list as well, thanks!

 

BTW, FYI, when you fill compressor with oil, it may say use 150 pag oil. Look for gm bulletins update website shows us to use the light weight pag(ester) oil on these older vehicles.

 

In addition to whatMike 1992c1500 said, you need to make sure that your evaporator and hoses are all cleaned out of any contaminants or particles before you hook all your new A/C parts together.

Yes, the use of a good UV dye is a good idea. Once you get the system back together, you need to pull down the vacuum to -28 to -30 PSI for at least 30 minutes or more, and preferably when its warm out, or you have a place that is not in cold weather outside, in order to get any moisture boiled out along with the atmo. Make sure you add the proper amount of PAG oil to your system, and the same with the R-134A content for your A/C system.

You want 30-40 PSI on the low side, and at the very least 160 PSI on the high side, and preferably higher then that, but not too high. Make sure you put some PAG oil on any sealing surfaces like o-rings too. And, as I always advise, make sure you are protecting yourself from any A/C leak or any possible explosion with good thick gloves and protective eye-wear, when you pressurize the system with the refrigerant.

 

All above is good advice, but I'll add my 2 cents as I did almost the same as you Tim. Change out both the High and Low service valves, cycling and pressure switches and put in new O rings everywhere.

 

thanks for all the advice on here, i'm slowly getting everything done. battling steady rain, darkness, and my job haha.

update as of tonight:

compressor replaced
condenser replaced
accumulator replaced
hard lines removed for flushing/inspection

test cranked the engine after installing new compressor (pre oiled) no more rattling!