TM10-3930-660-20 18-5. PISTON PUMP- TEST/REPLACE (Cont’d) 4. 5. REMOVE BLOCKING MATERIAL FROM BOOM. INSTALL TRANSMISSION COVER, PARA.  16-6. CAUTION Piston pump must be purged of air before engine is started. Refer to para. 18-3 for purging instructions. Failure to purge air as directed may result in severe damage to piston pump. 6. PURGE AIR FROM THE PISTON PUMP, PARA.  18-3. TESTING 1. 2. PREPARE AND SET-UP THE IN-LINE FLOWMETER. A TEST TEE SHOULD BE INCLUDED WITH THE FLOWMETER. MAKE HYDRAULIC CONNECTIONS TO FLOWMETER. a. b. c* d. e. f. Tag and disconnect inlet hose (l). Install test tee fitting from flow meter in place of inlet hose (1) at pump (2). Connect the inlet hose (1) to one side of the flowmeter test tee. Connect the other side of the flowmeter test tee to a hydraulic hose. Connect the other end of hydraulic hose to the fitting on the outlet port of flowmeter. Tag and disconnect the pump output hose (3) from the tee (4) on the pump  (2). Plug output hose (3) to prevent dirt from entering the hose. Connect a test hose from tee (4) to a tee at the inlet port of the flowmeter. 18-15