User manual BENDIX PP-3 TRAILER SUPPLY VALVE

[. . . ] The driver cannot, in this condition, overcome the emergency application of the trailer brakes by holding the PP-3TM valve button in. If the driver should hold the button in as emergency line pressure bleeds down from the 40 psi range to approximately 30 psi, the tripper piston will move and open the tripper exhaust in the PP-3TM valve. Emergency line air will exhaust through the tripper exhaust and hold the trailer brakes applied. that no air escapes at the open trailer service hose coupling. When system pressure reaches approximately 60 psi, the PP-3TM valve button should be pushed in. [. . . ] At a minimum, the PP-3TM valve should be inspected every 12 months or 3600 operating hours, whichever comes first, for proper operation. Should the PP-3TM valve not meet the elements of the operational tests noted in this document, further investigation and service of the valve may be required. REMOVING AND INSTALLING REMOVING 1. INSTALLING When installing the PP-3TM valve, refer to Figure 2 for proper connections along with following explanations: 1. Supply line from tractor reservoir is connected to supply port of PP-3TM valve. Delivery line from PP-3TM valve delivery port is connected to tractor emergency port of TP-3TM valve. Two (2) ports marked "Del" on upper PP-3TM control valve body are plugged and must remain plugged. OPERATING AND LEAKAGE CHECKS To make the following operating and leakage checks, an accurate test gauge installed in a spare hose coupling is required. The vehicle dash gauge should be checked for accuracy against the test gauge prior to making these tests. Block and/or hold the vehicle by a means other than air brakes during these tests. Connect assembled hose coupling and test gauge in tractor emergency hose coupling. As reservoir pressure builds up there should be no pressure reading on test gauge. When system pressure reaches the 30 to 40 psi range on dash gauge make and hold a foot or hand valve application and observe 2 DISASSEMBLY PP-3 PUSH-PULL VALVE 1. Button pin (1) Figure 3, button (2) and mounting nut (3) are normally removed when valve is removed from vehicle. Remove two lower body cap screws (4) and lock washers, then lower body (5) with cover (6). Insert rod or punch in upper plunger pin hole and hold plunger (11) from turning while inlet and exhaust valve nut is removed. CLEANING AND INSPECTION OF PARTS Wash all metal parts in mineral spirits and then dry. In particular, make sure supply port in PP-3TM valve upper body, tripper by-pass slot, and tripper exhaust port in cover are thoroughly cleaned and unrestricted. Inspect all parts for excessive wear or deterioration. TM Inspect seats in upper and lower body for nicks and burrs. Inspect plunger and tripper piston bores in bodies and cover for deep scratches or nicks. Replace all parts not considered serviceable during these inspections, especially o-rings and valves. ASSEMBLY Prior to assembly, lubricate o-rings and bearing surfaces with silicone lubricant Bendix Pc. [. . . ] If the work is being performed on the vehicle's air brake system, or any auxiliary pressurized air systems, make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle. If the vehicle is equipped with an AD-ISTM air dryer system or a dryer reservoir module, be sure to drain the purge reservoir. Following the vehicle manufacturer's recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle. Never connect or disconnect a hose or line containing pressure; it may whip. [. . . ]