This article initially appeared in PS 774 (May 17), p. 20.
Make sure you keep a close eye on the 621G scraper’s cab air filter, especially after a heavy rain.
The filter’s access door has a series of louvers that allows open air flow. Problem is, the louvers also allow water from rain and cab run-off inside the door. That water fills the channel along the inside bottom of the door.
If there’s too much water, it overflows the channel and the air filter soaks it up like a sponge. A soaked filter element gets moldy real quick!
Channel fills with water and overflows, soaking filter
You may also see buildup from water that seeps past the drain hoses attached to the A/C drip pan. The hoses are installed with a grommet that fits into a hole in the plastic drip pan. But the grommet doesn’t fit tight and leaks.
Water also seeps past rubber grommet
Replace a wet or moldy filter element with NSN 4310-02-602-0614. Then follow the instructions in TACOM GPA 17-008. It tells how to drill two drain holes in the door channel and add two O-rings, NSN 5331-01-333-6444, to the A/C drip pan grommet. See message at: