SERVICE MANUAL TROUBLE SHOOTING THE CR BRAKEMASTER UNIT SYMPTOM PROBABLE CAUSE REMEDY Air is exhausted from exhaust 1.  Inlet side of compressor con- Consider changing compressor port when compressor is in nected to outlet side of tur- inlet connection.  Consult ve- the stand-by mode. bocharger. hicle manufacturer. 2.  Check valve at outlet port Clean or replace check valve stuck open. assembly. System air pressure bleeds 1.  Leak in air line connection(s). Tighten or replace fittings. off rapidly when air using equipment is not being 2.  Leak in air line or reservoir. Repair or replace faulty item(s). operated. 3.  Check valve at outlet port Clean or replace check valve stuck open. assembly. Compressor runs continuous- 1.  Leak in air line connections. Tighten ori- replace fittings. ly (will not go into stand-by 2.  Leak in air line or reservoir. Repair or replace faulty item(s). mode). 3.  Compressor defective. Rebuild or replace compressor. 4.  Unloader valve stuck open. Clean or replace unloader valve assembly. 5.  Compressor capacity too low Install larger compressor. for vehicle. Compressor goes into "stand- 1.  Leak in air system. Correct leak. by" mode but cycles rapidly. 2.  Check valve in CR Brakemast- Clean or replace check valve er outlet port stuck open. assembly. 3.  Defective seal in unloader. Repair unloader valve. 4.  Unloader sleeve defective Replace sleeve. Air flows from exhaust port 1.  Unloader valve stuck open Rebuild unloader valve. when compressor is attempting 2.  Seat of unloader valve chipped Replace seat assembly. to build up pressure in air or nicked. system. 3.  Piece of dirt or foreign mater- Replace seat assembly. ial stuck in unloader valve. Compressor attempts to build 1.  Refer to "Compressor runs pressure but system pressure continuously" of Trouble Shoot- will not build up ing Guide. 2.  Line between compressor and Replace line or remove blockage. exchanger blocked. 3.  Check valve in outlet port Clean outlet and replace check stuck closed. valve. 4.  Pressure sensing device de- Replace fective. 5.  Blockage in air line between Remove blockage. compresor and sensing device (Note: If safety valve of ex- changer opens, blockage is after unit). CTS-4079 - CHAPTER XIV - Page 21