massey 390 a/c question help?

[americarkid]

do any of you gentlemen know where the expansion valve, orifice tube filter is on a 390 cab tractor ? I found the low side filler but cant even locate the highside to hook a gauge to check. i think i have an obstruction and want to change the filter inline. any help appreciated

 

[Harry in Ky]

What make you think you have an obstruction? Give us some details of what's going on, and let's do bit of troubleshooting before you start opening things up. Do you have a gauge manifold,and do you know how to use it? If not you'll do more harm than good by diving in and changing parts. Lets start with the symptoms first, then figure out where to go next.