TM 10-3930-659-20 5-9. AIR CLEANER MAINTENANCE (Con't). WARNING If  NBC  exposure  is  suspected,  all  air  filter  media  should  be  handled  by  personnel  wearing protective   equipment.      Consult   your   NBC   Officer   or   NBC   NCO   for   appropriate   handling   or disposal procedures. a. AIR FILTERS REPLACEMENT 1. Remove wingnut (1) and cover (2) from air cleaner housing (8). 2. Remove wingbolt (3) and primary air filter (4) from air cleaner housing (8). 3. Remove nut (5), seal (6), and secondary air filter (7) from air cleaner housing (8). 4. Remove dust valve (9) from cover (2). 5. Install dust valve (9) on cover (2). 6. Install secondary air filter (7) in air cleaner housing (8) with seal (6) and nut (5). 7. Install primary air filter (4) in air cleaner housing (8) with wingbolt (3). 8. Install cover (2) on air cleaner housing (8) with wingnut (1). TA706859 5-22