Document zbRY2qLkojZ7dN1XKaRYKr1Mg

TROUBLE SHOOTING CHART (Hydraulic Brakes) CONDITION CAUSE REMEDY Lining Wear. See Pege 2 Braka Shoe* out ol adjustment. See Page 2 Fig. 13 Pedal Goes To Floorboard Leak in System. Pedal Adjustment Improper. Examine all wheel cylinders. Hue and connections. II no leaka, inspect cylinder* lor scored bore*. See Page 5- 7 1. 2. 3. 4. Brake Chambers 8. Pressure Gage 12. Application Valve 5. Air Compressor 9. Reservoir 13. Quick Release Valve 6. Air Filter 10. Drain Cock 14. Relay Valve 7. Governor 11. Safety Valve All Brakes Draff One Wheel Drags Vehicle Swerves To One Side No fluid in aupply tank. Air in ayatam. Improper fluid in eyeienu Pedal Ad|uatment Improper. Weak brake aboo aprlng. Brake ahoe bearing seltcd to anchor' pin. Brake aboo aet too eloaa to dram. Cupa distorted. Loom wheel brga. Creeac-aoaked lining. Shoee Improperly eet. Sea Bleeding. Page 2"3 See Bleeding, Page 2 ~3 Flush clean with alcohol. Re place any swollen eups. Bleed as shown on Pago S. See Page Replace apring. Free op and lubricate. See Page 6~"7 Replace cups, clean and bleed. adjust Rencv* with MACK Lining. See Page Dual shield looeo on axle. Front spring clips loose. Tighten shield and reodjuat brake*. Tighten clip*. Different make# o! lining. Linings vary in irietion. Replace with proper MACA lining. Tires iufleied improperly. Each tire inflated to same pressure. AIR BRAKES When chassis is equipped with an air brake sys tem, the brake shoe cams are actuated by linkage to brake chambers which are operated by air pres sure. An Air Compressor mounted on and driven by t;he engine, replaces the vacuum booster cylinder as the source of power. The service (foot) brakes are of internal, two shoe construction, applying on all four wheels. The shoes are operated by "S" shaped cams giving con stant lift. BRAKE SHOE ADJUSTMENT is made by jacking up the wheel and turning the worm shaft nut of the Slack Adjuster, which rotates the cam shaft with respect to the lever or chamber push rod, until the brake shoes are tight against the drum. See Fig. 11-A Then back off on the worm until the wheel is free. Apply the brakes and note push rod travel. This should be kept to a minimum, as given on page - 9 As the lining wears, the worm should be readjusted to retain the minimum push rod travel. The travel should always be set accurately so as to be the same for both brake chambers on a particular axle. Maintain at least 60 pounds air pressure while mak ing adjustments. AIR COMPRESSOR furnishes compressed air. to the reservoir. The compressor operates con tinuously while the engine is running, but the governor functions to unload the compressor dis charge Valves when 100,,ta,,J.Q5...pounds reservoir pressure is reached, thereafter allowing the com pressor to operate without any compression until the pressure drops to between 80 and 85 pounds. Every 18,000 miles the compressor head should be detached and the carbon removed. The discharge valves, springs and seats, also the unloader valves, should be cleaned. The passage allowing the pump ing of air from cylinder to cylinder when com pressor operates without compression, must be kept open, otherwise, the Safety Valve will blow off. The discharge line from compressor to reser voir should be checked at this time to insure un restricted flow. The unloader diaphragm should be inspected. The discharge valve lift is .042". The clearance between unloader valve stem and tappet should be set at .010" minimum and .015" maximum. A notice able increase over this clearance indicates carbon accumulation on valve seat. The compressor head is water cooled by connec tions to the engine cooling system. When water is drained from radiator and engine to prevent freez ing, the compressor head should also be drained by removing plug. The compressor is automatically lubricated by pressure from the engine oil circulation system. The oil pressure at compressor should be at least 5 pounds minimum at engine idling speed, and 15 pound minimum at governed speed. AIR CLEANER is fitted to the compressor for removing foreign matter from the air. Every 1500 miles remove the filtering material, wash