How many lbs of R-134a?

[Harmon]

I have conflicting opinions on this....

I have 86 Chevy c-10 with r4 system converted.  Put new dryer, orifice, and r4 compressor in.  Put cans of r134a in.  Blew semi cold a while, then stopped blowing cold...obvious leak.

I want to put dye in to find where it is leaking....BUT  I do not know how many lbs of r134a is needed in the system.

Anyone have an idea?

[KY..Rob]

36 to 40oz should do it.

[Skunksmash]

I'm scared to do this cause that little valve can get old and give a false reading. Only way to tell with 100% certainty is to completely drain the system.

[topp]

I'm scared to do this cause that little valve can get old and give a false reading. Only way to tell with 100% certainty is to completely drain the system.

So based on your logic above, you don't trust tire gauges either cause those valves ge told and give a false reading?
Same valve, different seal.  They either open and close or don't...They don't give false pressure....