User manual BENDIX PP-7 TRAILER SUPPLY VALVE

[. . . ] system air pressure, the button of the PP-7TM valve will be out and the park control valve will not deliver air to the control port of the PP-7TM valve. In this condition supply air cannot flow past the closed plunger inlet and the plunger exhaust valve is off its seat. With no air pressure on the control port, the control inlet is seated and the exhaust passage through the control piston is open. NOTE: If the vehicle is parked and system air pressure is above 50 P. S. I. , the park control valve will not be delivering air to the PP-7TM valve control port and the control inlet valve will be closed. In this case no air will be flowing from the delivery port of the PP-7TM valve. OPERATION - MANUAL OR AUTOMATIC EMERGENCY MANUAL In order to disconnect the tractor and trailer, the button of the PP-7TM valve is pulled by the operator. [. . . ] No two vehicles operate under identical conditions, as a result, maintenance intervals may vary. Experience is a valuable guide in determining the best maintenance interval for air brake system components. At a minimum, the PP-7TM valve should be inspected every 6 months or 1500 operating hours, whichever comes first, for proper operation. Should the PP-7TM valve not meet the elements of the operational tests noted in this document, further investigation and service of the valve may be required. should be within approximately 10 P. S. I. Reconnect the test gauge to the tractor-trailer supply line and depress the button of the PP-7TM valve. Note at what pressure (descending) the button of the PP-7 TM valve pops out and exhausts the tractor-trailer supply line. If the PP-7TM trailer supply valve fails to function as described or if leakage is excessive, it is recommended that it be returned to the nearest Bendix authorized outlet for a factory remanufactured valve. If this is not possible, the valve should be repaired using only genuine Bendix replacement parts, in which case the following should prove helpful. NOTE: Maintenance piece number 287367 kit is available for the PP-7TM trailer supply valve, which contains all the necessary parts to completely repair it, from any authorized Bendix outlet. Chock the vehicle wheels and drain all air system reservoirs completely. Disconnect all air lines leading to and from the PP-7TM valve and mark them for proper reconnection. Using a 1-5/16 inch wrench, remove the special thin nut which secures the PP-7TM valve to the panel and remove the valve. Mark the upper and lower body halves to show their relationship to each other. Remove the two 1/4 inch-20 cap screws, that secure the lower valve body to the upper valve body, using a 7/16 inch wrench. Remove and discard the square cut sealing ring (3) between the upper and lower body halves. Remove the end plate (4) and o-ring (5) from the lower body and discard the o-ring. Remove the large (8) and small diameter o-rings (9) from the piston and discard them. Remove the o-ring retainer (11) and remove and discard the o-ring (12). Remove the inlet exhaust valve (13) and return spring (14). 5 OPERATING AND LEAKAGE CHECKS To perform the following test, an accurate vehicle test gauge installed in a spare hose coupling is required. The vehicle dash gauge(s) should be checked for accuracy against the test gauge prior to making these tests. With the PP-7TM trailer supply valve button out and the parking control valve in the exhaust, or brakes applied position, build the air system pressure to governor cut-out. Apply a soap solution to the exhaust vent and the plunger stem of the PP-7TM valve to check for leakage. [. . . ] Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components. Do not attempt to install, remove, disassemble or assemble a component until you have read and thoroughly understand the recommended procedures. [. . . ]