A/C purge-evacuation-activation

[hanomon]

I'm sticking with the stock 1975 280 A/C set-up evap condenser and reciever/dryer.

 

The only major component replaced will be the compressor.

The stock Vette/Denso unit will be used on this LT-1.

 

My question (after researching all previous posts using the search function re: airconditioning) is what method and or product would be best for flushing out the old R-12 tainted oil from the evap/condenser?

 

The reciever dryer has been exposed over time so the desicant may be exhausted? Should this component be replaced to accept the new R-134A?

 

The compressor was an R-134A system. I know of the corossive potential associated with mixing these two different type refrigerants especially on compressor seals/O-rings.

 

Also I remember reading somewhere about an alternative refrigerant? Any help here would be cool. (couldn't resist that one)

Thanx guys.

[80LS1T]

First of all....yes replace the receiver/drier for sure. That thing is a basically a sponge for moisture(moisture in the air). If that has been open to the atmoshpere for too long it will for sure be junk. No matter how long you hold a vacuum on the system.

 

There are special chemicals that are made for flushing A/C system but you also need special equipment to flush them. You could try flushing it out with some R134a oil by just pouring it in one end and waiting for it to come out the other?

 

 

Guy

[Capt_Zorro]

80LT1 is correct, the dryer will need to be replaced. I had a hard time finding one that would work. Ended up costing about $55.00 for it. A good auto parts store will have air cond. flush. It's an aerosol like brake cleaner with a flexible line and plug that will fit into the lines. You have to disconnect the compressor and condensor lines and blow them out with the cleaner. Then use compressed air to finish drying them out. I did mine last month, flushed out the system, had some new lines made up to go from the Sankyo compressor to the Z car system. I think PEG oil is recommended to use with the R134 but better check to make sure. Pulled a vacuum on the system for about an hour and then charged it up. It promptly blew an "O" ring in the evaporator... the way my luck has gone here lately I should have expected it. When my broken finger gets better I'll have something to do. Probably be cold weather by then tho.

 

Adios Amigos,

[hanomon]

Thanks for the input. will get the flush kit and replace that reciever/dryer. BTW all fittings are 45deg. flair. No line O-rings.

[80LS1T]

Are they hard lines or rubber? If you are using the old R12 lines you may have a problem keeping the new R134a in the system. R134a lines are "barrier" style hoses. Old R12 molucules(sp?) are larger than the R134a so they cant just go threw the microscopic holes in the hoses, however R134a mulcules are much smaller and can possibley just go right through the old R12 hoses. Now its not going to just go right through the hoses but you may notice your refrigerate level getting low over a period of time but no leaks can be found.

 

If you have all new lines/hoses then just disregard what I just said!

 

 

Guy

[hanomon]

Thanks for all the input. 80LT1 makes a good point in that when replacing A/C plumbing the hose material must be able to contain the refrigrant. It is all copper except the two hoses on the compressor and yes they are barrier type. Just beacuse its steelbraided and crimped dosen't mean it will hold refrigerant. The guys at Crown hose pros explained this. Got the new reciever/dryer from autoparts store and, Dan provided an exelent test sequence via PM. Thanks again Dan. This site and you guys ROCK!