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I am refilling my subs a.c. system(front and rear)with r134a and was wondering if any of you guys had a ruff estimate on how much 134a the system should hold. I already put about three and a half pounds in. The front is running ice cold but the rear is not. The refrigerant pressure only reads about 40 lbs. on my gauge. Any help would be appreciated.

5.25lbs

Thank you very much /forums/images/icons/smile.gif

The expansion valve in the rear unit might be bad.

Fill 80-85% of the original r-12 when using r-134 as a replacement. 40 pounds on the low side sounds alright. Keep in mind that a warm engine compartment or ambient tempature will cause that number to rise. Winding it up will cause it to move too.