You will have to replace the low pressure line that is leaking .. I have included a diagram of the A/C fitted to the 1991 420SEL .. you said yours was retrofitted but in principal they all work the same .. hopefully with it being a retrofit you can just replace the actual line !!
Hope this helps
April, 9, 2010 AT 6:55 AM
IT IS THE VALVE THAT LEAKS, NOT THE LINE. WHEN
CHARGING THE A/C, I NEGLECTED TO TURN ON THE ENFGINE, AND I GOT A HIGH PRESSURE WARNING. WHEN I DISCONNECTED, GAS AND OIL SPAT OUT OF THE VALVE. WHEN I TRIED TO CHARGE AGAIN WITH THE ENGINE RUNNING, IT CHARGED NORMALLY, BUT AGAIN THE VALVE WAS INCOMPETENT WHEN I DISCONNECTED THE CHARGING DEVICE. I DO NOT KNOW HOW TO ORDER THE VALVE (DON'T KNOW WHAT CORRECT TERMINOLOGY IS). SEE ITEM ABOUT VALVE CORE KIT AND DON'T KNOW IF IT APPLIES TO
THIS OR HOW TO INSTALL IT.
DON'T UNDERSTAND YOUR RESPONSE ABOUT CHANGING LOW PRESSURE LINE.
WHY CAN'T I JUST RPLACE THE VALVE. I BELIEVE I DAMAGED IT BY DELIVERING A CHARGE WITHOUT TURNING ON THE MOTOR (AND THE a/c). GOT A HIGH PRESSURE WARNING AND WHEN I DISCONNECTED GAS AND LUBRICANT ESCAPED FROM THE VALVE. CHARGING WITH THE ENGINE ON WENT NORMALLY, BUT AGAIN VALVE WAS INCOMPETENT WHEN DISCONNECTING.
April, 9, 2010 AT 5:47 PM
The valve usually is a built in part of the actual line and cannot be removed seperately?
April, 10, 2010 AT 8:04 AM
This is not correct. Replacement valves are made by 4-seasons and schrader. I have ordered a replacement valve kit. It is better to give no answer than one that is incorrect. Please return $7 donation. Thank you.
April, 11, 2010 AT 5:50 AM
As you have said previously, yours is an aftermarket A/C system ... not all systems come with removable valves ? so technically .. my answer was not incorrect in most cases .. I will forward your refund request to the forum administrators !
April, 11, 2010 AT 11:35 PM
We are sorry we could not help you this time. Your donation has been refunded.