TM 10-8400-203-23 Change 10  26-13 Outside Screw Ratchet Buckles Adjustment Straps Earcup to Earcup cable Earcup Notch Hook and Pile Fastener To repair any components of the Impact Liner Assembly, simply replace parts as necessary.   To repair the retention system, take out impact liner assembly. Starting with the right side, unscrew the retention straps from the upper inside faceguard strut while holding the outside screw in place. Unscrew the retention straps from the inner backside of the helmet shell. Release the ratchet buckles on the back of the helmet, and pull the adjustment straps through. Push/pull the adjustment straps free, through and out of the headset tunnels and struts. Remove the earcup to earcup cable from the nape strap. Remove earcups from damaged retention system by pulling apart retention system cloth free from earcup notch. Remove damaged retention system.   To install new retention system, place right earcup on top of hole opening on right side. Insert edge of retention system cutout into the earcup notch. While pushing up on earcup from bottom, slide remaining retention system edge into earcup notch until earcup is completely engaged.  Attach the retention system to helmet shell, by screwing the retention straps onto the inside of the struts, and to the inside rear of helmet shell. Repeat procedure for second earcup.  Slide earcup adjustment strap through the strut, through the headset tunnel and finally through the ratchet buckle in the rear. Secure earcup tension adjustment strap by fastening the ratchet buckle. Repeat for opposite side. Secure earcup-to-earcup cable within the nape strap by fastening the cable into the hook and pile fastener.    Figure 26-10. Retention System 26-8 REPAIR - Continued Impact Liner Assembly Upper Inside Faceguard Strut Helmet Shell Headset Tunnel Nape Strap Earcup Retention System Cloth Retention Straps