AC gurus -

I have read through all the threads and I'm aiming to hook up my welding gas cylinder to pressure test my AC system.

My question is: What connection do I get to go from the AC hose (R12 flared fitting) to the gas regulator - 1/4 straight threads.

Grainger / McMaster etc. give me no options.

Help :-) I'm trying to do it right.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Your Nitrogen cylinder ?

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I am not able to visualize where you are needing this connection to span.....
Do you not need a hose from the output of the Nitrogen regulator... to your R12 manifold ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Sounds like he is going to substitute the welding gas to me.

Find a hose supply store, tell them what you want to connect and how long and they should be able to help. You may have to shop around a little.

hoses in Boston

I'd try AIT first.

__________________
Jim

The AC side fittings are generally SAE 45 degree flare for 1/4" tubing. ( not inverted flare brake tube ) Any decent auto parts or home center will have something.

As for the regulator side, most use a male thread ball seat fitting that I can't recall the name of. A welding supply should have this. If your regulator has a hose barb with a clamp, attach a piece of at least 100 PSI working pressure hose. ( Fuel injection hose , Gates Lock On type hose works also. )

Bought my N2 regulator rig at the welding supply shop (it's a 'Turbo Torch') and bought a brass fitting (SAE 45 degree) that was threaded on the non flare end (1/8NPT). I test at 100psi - no more, no less. The fitting fits R-12 charging hose for auto applications.

That is a good answer..

' a welding gas ' may not be safe for this.... even Oxygen under pressure can cause an explosion..
let us know more..
we do not want you to get hurt..

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Since the argon component of the welding gas has a smaller molecule than nitrogen. I use argon for pressure testing.

Argon and Nitrogen are noble gases and great for pressure testing an AC system..

' Welding gases ' is too broad a term to endorse because even something which might seem safe.. like oxygen ... when under pressure in contact with any oil can cause an explosion.. and of course the inside of an AC system has oil.

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Hey sorry for thread abandonment - i need to go from the output of a regulator to the 1/4" flare male fitting to hook up to the charging hose on my gauge set.

i now see if i want to pressure test that Nitrogen regulators are standard 1/4" flare.

i was trying to sub in 75% Argon / 25% CO2 standard MIG welding gas since that's what I already have.

good suggestion on the custom built hose.

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

A lot of people use CO2 even though I do not like it... for no particular reason other than it is part oxygen ...

but I think Vstech uses it ....

Whatever things are directly hooked to your cylinders ... make sure they can handle more pressure than they contain..

and always wear goggles.... I have seen the faces of gauges get blown off...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

It would be a good idea to define the gas ( in a later post our guy said 75 Argon / 25 CO2 )




This is so wrong. According the the Google machine, The six naturally occurring noble gases that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn)

Nitrogen isn't on the list









Dihydrogen Monoxide has oxygen in it also, so dumping some on a fire will make it flare up using your logic.

I use CO2 carbon dioxide to pressure test AC systems because I keep it for MIG welding rusty metal and as a portable "air" source for air tools and such. If you use it for inflating tires, it will leak out at a faster rate due to the molecules being smaller than nitrogen. ( Nitrogen makes up ~ 75% of the air we breathe. )

In HVAC/R work N2 is used because it is 1-inert, 2-cheap, 3-seems to "dry" the system.

CO2 can work, I used to use it, but N2 is drier which tends to give better results. I am sure Argon/CO2 would work for pressure testing, just make sure you evacuate completely then pull a 29.9mmHg vacuum in ambient above 70F (preferably in low/no humidity) for a good long time & you should get good results.

Hey Charlie Foxtrot, do you remove the valve core for faster evacuation and charge? How big a difference does it make time wise in automotive AC in regards to removing vs not removing the core?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Removing the core won't make much difference time wise in pulling a vacuum and when you remove the hose, air will enter the system negating the reason to pull a vacuum in the first place.

Long vacuum pulls are to let moisture evaporate / gasses to escape small voids ( like under bolt holes )