Calling Air Conditioning Guru's

[jgkurz]

Hi Folks,

 

I have a 77 280z that has the original R12 A/C. It works well except for a slow leak at the compressor front shaft seal. It takes a couple years to stop working but I'm sick of refilling it. The local A/C guy did a refill today but when I got home I noticed a fair amount of bubbles still in the sight glass. I called him to asked if he could add a touch more R12 and he said no problem but he said having the freon a bit low would reduce the pressure on the high-side a bit which might stop/postpone the leak. He also recommended using it more to lube the seals. I'm not sure I buy into this so I want to ask the question here. He would add more R12 for free didn't recommend it on such an old system. Is there any truth to this? Should I have enough R12 added so the bubbles are reduced?

 

Also, is swapping my good A/C clutch to a new compressor a big problem? The rebuilt compressors without a clutch are half the price of ones with a clutch.

 

P.S. I'd rather not convert to R134 unless I absolutely have to.

[zcarnut]

... is swapping my good A/C clutch to a new compressor a big problem? The rebuilt compressors without a clutch are half the price of ones with a clutch...

 

Even using the special tools, it’s not easy…

 

First, get the FSM and read the procedure in the AC section. The clutch hub must be removed using a special puller that most ac shops would have and maybe would let you borrow. I made mine by modifying a GM clutch hub puller by re-treading one end with the correct metric thread pitch.

 

There are locknuts and shims that must be carefully removed and saved for re-use, and then the clutch pulley can be removed with a standard three-jaw puller. However, the clutch coil is attached with six Phillips head screws that have been “caulked” by the factory so they will not loosen. To remove them you can try an impact wrench but that usually just strips out the head of the screw. I generally end up removing them with a left-handed bit and drilling them out. Fortunately, Nissan supplies new Phillips screws with a new clutch, but I don’t know about the aftermarket guys.

 

During the re-install you must set the correct clutch hub gap using shims. It sounds tough, but like changing rear wheel bearings, the first one you do will be the worst. After that they get simple (and I‘ve done about six or seven).

[jgkurz]

Even using the special tools, it’s not easy…

 

First, get the FSM and read the procedure in the AC section. The clutch hub must be removed using a special puller that most ac shops would have and maybe would let you borrow. I made mine by modifying a GM clutch hub puller by re-treading one end with the correct metric thread pitch.

 

There are locknuts and shims that must be carefully removed and saved for re-use, and then the clutch pulley can be removed with a standard three-jaw puller. However, the clutch coil is attached with six Phillips head screws that have been “caulked†by the factory so they will not loosen. To remove them you can try an impact wrench but that usually just strips out the head of the screw. I generally end up removing them with a left-handed bit and drilling them out. Fortunately, Nissan supplies new Phillips screws with a new clutch, but I don’t know about the aftermarket guys.

 

During the re-install you must set the correct clutch hub gap using shims. It sounds tough, but like changing rear wheel bearings, the first one you do will be the worst. After that they get simple (and I‘ve done about six or seven).

 

Great info. Thanks Steve.

[Clifton]

I don't know what you did with this but running it a little low on the pressures won't slow a leak much. The volume is small and the pressures so high to begin with that dropping it 10-30 psi won't get you much other than warmer air and maybe an extra day before you run out. I gave up paying/trusting a/c guys along time ago. If I were you I would atleast buy some gauges. Then you can check and add some too if you want. You can get electric vac pumps fairly cheap too if you want to do it all. I wouldn't bother with the venturi vac ones.

 

You can replace the shafts seal too but unless you vac and refill yourself it might not be worth doing, if it leaks the money you saved will be more than spent paying some guy to vac and fill.