Indian Creek 'Cats

Cup Seal Inspection and Replacement

Updated: 11 May 1999

Part names in italics refer to parts listed in the official schematic diagram. See your manual or the web site for locations.

Strip the 'gun and remove the Upper Receiver. Refer to your manual and the ICD web site for details.
Find the valve and remove the aluminum Valve Seat, pictured below (#1).
Pull out the Value Pin Ass'y. (#1, #2, #3)
Inspect the valve parts for foreign objects, abnormal wear, or damage. A uniform groove in the Cup Seal is normal, but when the groove gets too deep the valve can restrict gas flow. (#3) This is a standard wear part that will need to be replaced periodically.
CAREFULLY unscrew the two pieces of the Valve Pin Ass'y. The schematic shows this as one part, but it's actually a brass body, a SS stem, and a Teflon(?) cup seal. (#8) You will need to use Vise Grips or pliers with padded jaws to get this thing apart. The pictures below (#4, #5) depict the use of a 12mm socket shimmed with foil to hold the valve body, and Vise-Grips padded with a large rubber band to grip the valve stem. This allowed the parts to be disassembled with no perceptable damage to any of them.
Pull the old seal out with a paper clip or dental pick. (#7)
Put a new seal in the valve body, or flip the old seal over and use the other side until it also wears out.
Screw the Valve Pin Ass'y back together, making sure the seal seats evenly, and tighten using the same method you used to loosen the parts.
Put the marker back together and see it if works.