SD-08-2418 ® Bendix® AD-IS® and AD-IS® PuraGuard® (Oil Coalescing) Air Dryer and Reservoir Systems RES GOVERNOR RESERVOIR (2) PURGE VALVE PRESSURE PROTECTION VALVES (4) DESICCANT CARTRIDGE (PURAGUARD® OIL COALESCING SHOWN) DESICCANT CARTRIDGE (STANDARD SHOWN) MOUNTING HOLES (4) GOVERNOR SAFETY VALVE PURGE RESERVOIR UNL GOVERNOR UNLOADER (2) MOUNTING BOLTS (3) 22 SEC DELIVERY TO SECONDARY RESERVOIR 21 PRI DELIVERY TO PRIMARY RESERVOIR 23 AUX2 AUXILIARY DELIVERY PORT HEATER / THERMOSTAT EXH GOVER
GENERAL SAFETY GUIDELINES WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH: When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES: ▲ Park the vehicle on a level surface, apply the parking brakes and always block the wheels. Always wear personal protection equipment. ▲ Stop the engine and remove the ignition key when working under or around the vehicle.
DESCRIPTION The function of both the Bendix® AD-IS® (Integrated Solution Air Dryer) air dryer and reservoir system and the Bendix® AD-IS® PuraGuard® oil coalescing air dryer and reservoir system is to collect and remove air system contaminants in solid, liquid and aerosol form before they enter the brake system and to provide—as a module—heavy vehicles with an integrated vehicle air dryer, purge reservoir, governor and a number of the charging valve components in a module.
Note 1: The Bendix AD-IS air dryer and reservoir system purge piston has a purge control channel drain. This allows any condensation in this area to flow past a diaphragm in the top of the purge piston and out through a channel in the middle of the central bolt of the purge assembly to be drained. During the purge cycle this drain is closed.
DESICCANT BED OIL COALESCING FILTER (BENDIX® AD-IS® PURAGUARD® OIL COALESCING AIR DRYER) PURGE CONTROL CHANNEL PURGE ORIFICE DELIVERY CHECK VALVE (CLOSED) PURGE RESERVOIR PRESSURE PROTECTION VALVES GOVERNOR UNLOADER PORT SUPPLY PORT A PURGE VALVE (OPEN) TURBO CUT-OFF VALVE ENGINE (CLOSED) TURBO COMPRESSOR SAFETY VALVE B C D PRIMARY PORT (PRI) PURGE RESERVOIR DRAIN VALVE SECONDARY PORT (SEC) EXHAUST PRIMARY RESERVOIR SECONDARY RESERVOIR AUXILIARY PORTS (TO ACCESSORIES) DIAGRAM SHOWS ALL
The actual regeneration of the desiccant drying bed begins as dry air from the purge reservoir flows through the purge orifice into the desiccant bed. Pressurized air from the purge reservoir expands after passing through the purge orifice; its pressure lowers and its volume increases. The flow of dry air through the drying bed regenerates the desiccant material by removing any water vapor adhering to it.
(Recommended intervals for trucks equipped with nonBendix compressors are 6 months (50,000 miles), one year (100,000 miles) and two years (200,000 miles), respectively.) 2. Visually check for physical damage, such as chafed or broken air and electrical lines, and broken or missing parts. 3. Check the AD-IS® air dryer and purge reservoir bolts for tightness. See Figure 1. Re-torque the three air dryer bolts to 360–420 in-lbs and the four purge reservoir bolts to 300–360 in-lbs. 4.
Warm the thermostat and heater assembly to approximately 90° F and again check the resistance. The resistance should exceed 1000 ohms. If the resistance values obtained are within the stated limits, the thermostat and heater assembly is operating properly. If the resistance values obtained are outside the stated limits, replace the heater and thermostat assembly. 6. Pressure Protection Valves. Observe the pressure gauges of the vehicle as system pressure builds from zero.
BRAKING SYSTEM PROTECTION Maintenance Kits The Bendix AD-IS air dryer allows the system to maintain one brake circuit up to about 100 psi even after a pressure loss in the other brake circuit. This allows a vehicle to be moved (in an emergency), but with reduced braking capacity. Compare this to a conventional system, where a loss of pressure in one service tank leaves the vehicle with a limited number of reduced braking capacity applications before the parking brakes automatically apply and stay on.
GOVERNOR GASKET (SPECIAL GASKET, SEE ASSEMBLY NOTE 6) SMALL O-RING GOVERNOR (NON-ADJUSTABLE, 130 PSI CUT-OUT) BOLTS CHECK VALVE BODY SPRING LARGE O-RING ADAPTER FIGURE 6 - BENDIX® AD-IS® AIR DRYER AND RESERVOIR SYSTEM DELIVERY CHECK VALVE DELIVERY CHECK VALVE CLEANING PROCEDURE CLEANING & INSPECTION (Note: This is only required if system pressure does not build after temporary bypass is completed.) 1.
ASSEMBLY 1. Lubricate the smaller o-ring and check valve body with a heavy duty lithium grease. 2. Install this o-ring on the check valve body by sliding the o-ring over the set of four tapered guide lands. The o-ring groove holds the o-ring in its correct location. 3. At the other end of the check valve body, the spring is installed over the set of four straight guide lands.
NOTES 12
BENDIX®AD-IS® AIR DRYER AND RESERVOIR SYSTEM TROUBLESHOOTING CHART SYMPTOM CAUSE 1. Dryer is constantly “cycling” A. Excessive system leakage. or purging. B. Defective delivery check valve. REMEDY A. Test for excessive system leakage. Allowable leakage observed at the dash gauge: - Single vehicle - 1 psi/minute. - Tractor trailer - 3 psi/minute. Using a Bensoap solution, test vehicle for leakage at the fittings, drain valves and system valves and any accessories (i.e.
BENDIX®AD-IS® AIR DRYER AND RESERVOIR SYSTEM TROUBLESHOOTING CHART SYMPTOM CAUSE REMEDY 2. Wa t e r i n t h e v e h i c l e A. Maximum air dryer inlet temperature is A. Check for excessive carbon build up in the compressor reservoirs exceeded due to improper discharge discharge line. Replace if required. Make certain that the line length. discharge line length is at least 6 ft. Increase the discharge line length and/or diameter to reduce air dryer inlet temperature. B. Air system charged from outside B.
BENDIX®AD-IS® AIR DRYER AND RESERVOIR SYSTEM TROUBLESHOOTING CHART SYMPTOM CAUSE REMEDY 4. Constant exhaust of air at the A. Air dryer purge valve leaking A. With the compressor loaded, apply a soap solution on the air dryer purge valve exhaust excessively. purge valve exhaust, to test for excessive leakage. Repair or unable to build system or replace the purge valve as necessary. pressure. (Charge mode.) Refer to Technical Bulletin TCH-008-040. B. Purge valve frozen open - faulty heater B.
BENDIX®AD-IS® AIR DRYER AND RESERVOIR SYSTEM TROUBLESHOOTING CHART SYMPTOM CAUSE REMEDY 9. “Pinging” noise excessive A. Single cylinder compressor with high A. A slight “pinging” sound may be heard during the system build during compressor loaded pulse cycles. up when a single cylinder compressor is used. If this sound cycle. is deemed objectionable, it can be reduced substantially by increasing the discharge line volume.
