Mack ch 613 air conditioner leak

[john510]

I have a 1995 ch 613 model with an air conditioner leak in it and put florescent air conditioner dye int he system and charged it. It works fine but slowly leaks out after 4-6 days , after looking for the leak I seen some of the dye on top of two line against the firewall as indicated by the arrows in the picture.

It looks as if the leak may be coming form the inside of the cab by the core but not able to see and of the dye inside since its so tightly sealed. I removed the inside cover exposing the heater and air conditioner core and still see no dye. I think it may be where the connection is on the back side by the firewall but having difficulty removing the air duct pipe that is some how attached up top in the dash, the lower half is loose but something is holding it up top and I don't want to damage anything, any help on this would be greatly appreciated.

[keg1]

If the duct your talking about is what I think my Ch had a screw or bolt that came in from the engine side of the firewall. I think it was behind something or above something where you might not see it from the ground.

[hatcity]

Is there a kick plate on the passenger side by the floor? It covers the computer. Remove that, and you can gain access to the upper screw

[turckster]

The leak is from the evaporator, you can remove the evaporator/heater core assly without removing the the whole hvac unit. Clamp the heater hoses and remove them from the core, recover the refrigerant and removed the lines and exp. valve. Slide the heater core/evaporator assly out together. There are a few clips that hold the two together. Replace the evaporator, expansion valve and dryer and any other components that need it. Make sure, when everything is assembled back together, that the exp. valve mount bolt is installed or this will happen again. The weight of the a/c lines will cause the exp. valve to move when the chassis is moving around, causing the copper tubing on the evap. to crack/break.