12-98. TM 9-2320-361-20 This task covers: a. Removal b. Installation INITIAL SETUP: APPLICABLE MODELS M764 REFERENCES (TM) TM 9-2320-361-10 TM 9-2320-361-20P EQUIPMENT CONDITION Parking brake set (TM 9-2320-361-10). 1. Remove pin (1) from shackle (3) and derrick base (4). 2. Remove shackle (3) and snatch sheave (2) from derrick base (4). 1. Install shackle (3) on snatch sheave (2). 2. Install shackle (3) and snatch sheave (2) to derrick base (4) with pin (1). 12-164