not long ago I installed a new expansion valve, compressor, high pressure and low pressure lines, and dryer, basically everything except the evaperator and condensor. I just got around to vacuuming out the system and I found that it would not reach full vacuum. so upon some investigation I found that the connection between the low pressure line and the front expansion valve is not sealing properly. the parts are all brand new and I installed new o-rings that I lubricated with ac oil before assembling, so I was pretty suprised to find this.

so I disassembled the offending parts and found that if i slip a thin o-ring around the base of the male fitting on the hose where it inserts into the expansion valve, it was able to pull a vacuum, but alas after one day it went from 30hg, to 25hg. so its still leaking.

the expansion valve is a GPD brand and the hose I think says goodyear on it. the o-rings are gpd also.

can I try a thicker o-ring to see if it sels better maybe? does any type of o-ring work on an ac system or does it have to be specific to ac lines? or should I get a new expansion valve of a different brand? I really dont want to try leak sealer since im using all new parts.

its an 01 grand caravan and I deleted the rear ac by using hoses for front ac only.

its the upper port in this picture where im having the trouble.


and this is the hose, its the end with the larger block

 

It uses a thicker oring originally

 

thanks, ill see if i can find something thicker