AC compressor

[Tommy Dat]

Hello All,  my 1980 L20B  720 AC compressor died on me.  What are my best options to replace/repair?  I am striking out looking for a replacement part number C3061.  Are there other makes/models that work?  Any recommendations for shops that rebuild these?  Any help is greatly appreciated.  Thanks

[iceman510]

Were you still using R12?  Planning to continue that?  I have one from an '81 if you are interested.  It was on a Z22, not L20B, but maybe usable.  I have not looked at any part numbers.

[Thomas Perkins]

I switched over to R-135a with my new system.

[Tommy Dat]

23 hours ago, iceman510 said:

Were you still using R12?  Planning to continue that?  I have one from an '81 if you are interested.  It was on a Z22, not L20B, but maybe usable.  I have not looked at any part numbers.

I had planned to start using the R135.  Can you use the new stuff in the old compressors?  

 

Do you know if the compressor that you have is good?  what are you asking for it?   thanks

[iceman510]

You would have to research yourself if R134 can be used instead.  It may not be recommended, and generally the lubricant and also the hoses (and o-rings) have different permeability for the different refrigerants.

 

I do not know for certain the condition.  It came off an engine assembly pulled years ago that I never used or ran.  $40 plus shipping?

[Thomas Perkins]

You can use R-134 a in the old system,I did.I had new connectors put on the old one so it would take the R-134a.Many a.c. places do not use R-12.I had my complete Nissan heating and air gutted and a complete new custom made system installed in mine.It cost 1200.If you buy the compressor from Rock Auto Parts,you will need this to fit it.It has the R-134a fittings.This is what is on mine.Midas Muffler shop put my R-134a connectors on my old system.They put R-135a in but figured the compressor was bad.They do a.c. work,but couldn't not find a compressor that would work with the old Nissan hoses with them fittings.This was over 5 years ago when Midas did this.If you can afford this system,it is so awesome.My new system is about 4 years old.09/04/2020 is when I got it all done.I had the same guy put this system.in as my Jasper engine in 2009.I have 105, 000 on the engine now.He installed the blue power wire that you see at the compressor.

Edited August 22 by Thomas Perkins

[Thomas Perkins]

See the a.c. hoses,they travel across the firewall now,old one's went across engine.That is the sun shining on the hood insulation.See the R-134a fittings with light blue caps.And the new heating and air control knobs on other picture.No more fan in the right corner, gone.The heater is hot,and a.c. is cold cold.Defroster works great.

Edited August 22 by Thomas Perkins

[powderfinger]

If the compressor on your truck is the same compressor that comes on the 85 720 with the z24 then you can do what I will likely do. I got my AC working for a few weeks then the 40 year old compressor started locking up. I have a spare but being that it is so old and has been sitting open for some time I am guessing that one will suffer the same fate.

 

I will likely use the compressor that came on the 86 D21 with the z24i and make new hoses using the compressor end from D21 hoses and the other end from the 720 hoses. I don't see the need to pay someone to install a completely new system. My AC actually was working very well until the compressor locked up.

Edited August 22 by powderfinger

[NC85ST]

What happened to the original compressor?

[Thomas Perkins]

He did something to it.I did not want any of that old stuff.

[Tommy Dat]

9 hours ago, NC85ST said:

What happened to the original compressor?

When I bought the truck the AC was not cooling.  I tried to charge the system and it began to blow cool air.  After a few minutes it stopped cooling.  I removed the hoses and checked for a clog by blowing compressed air through the tubing.  When I reconnected everything it blew cool for another minute before making a loud racket and then blowing hot air again.  I found a compressor at a Pull a Part but it was on a Nissan Z instead of the L20B so the pulleys do not align. 

I removed the compressor and the clutch and bearing seemed ok to my untrained eye.  There was rust in the casing.  The compressor seems to build pressure when turned my hand (suction on the intake and pressure out with your thumb covering the ports).  Since it was building pressure at such low RPM I thought maybe that the seals were bad?

[NC85ST]

I take it that you didn’t replace the dryer or expansion valve? I am definitely not an expert on a/c systems but I have revived a few. When you took it apart and blew out the lines, did it still have pressure, does it have pressure now? If it doesn’t then, of course you have a major leak. If the system was empty for a while, the dryer probably needs replaced. If you’re wanting to revive the system, I would go through and replace all the o-rings and flush the evaporator and condenser. You can get a/c flush at Autozone or Advance. Along with the dryer, I would replace the expansion valve also. 

[Thomas Perkins]

Put ultra violet dye in it so if it leaks,you will see the dye.I have it in mine.Always put a new dryer in it.

[bottomwatcher]

When a compressor takes a dump it often sends debris throughout the system which causes the new compressor to take a dump shortly afterwards. They make filters to protect the new compressor but reviving an old system is only sometimes successful. Dissect your old compress to look for damaged pistons. It's free and you figure out if there are metal particles in the system.

[Thomas Perkins]

My compressor hose busted when I was at McDonald's drive thru getting a milk shake.I opened the hood and green stuff was everywhere,and had a little fire.At first,I though the head gasket blew and anti freeze was the green stuff.It was the green dye in the a.c.I put the fire out.The dye got on the exhaust manifold.I found a used hose on 720 world from a guy in New Mexico.That was years ago.