Air Conditioning Freon Recharge
 

1980 300cd
AC System converted to R134a by a licensed and authorized MBZ repair facility in 2001.
Statement : I purchased a can of r134a and supply hose (1) kit (Quest 401P.
No pressure gages included.
Question: Can you instruct me the proper and safe way to top off my AC system.
i.e. conection, setup, procedure, engine status, rpm, state of recharge freon can (light, heavy, cold -etc).
As you can determine - my first time, I want to do it myself to save money, but I do not want to screw up.
The AC system is working fine, just not as cold as it was last summer.
Thanks. John

RE: Air Conditioning Freon Recharge
 

there is a sight glass on top of filter/drier bottle.

once the bubble is not present, it is fully charged.

charge from the low side.

RE: Air Conditioning Freon Recharge
 

To add to sleepwalker's post...

- Fill while the engine is running and the A/C is on.

- Keep freon can upside down while filling. Shake gently a couple of times during filling.

- If one pound doesn't top it off, two should.

- As sleepwalker said, use the low-pressure connection. It's the only one your kit will fit on. The high-pressure connection looks the same but requires a larger fitting. If you somehow managed to "force" a connection there, the refill can of freon would explode.

RE: Air Conditioning Freon Recharge
 

Thank you for the information and time.
Best Wishes, John

RE: Air Conditioning Freon Recharge
 

Thanks for responding and the advice.
Best Wishes, John