BENDIX SD-08-2418 manual Braking System Protection

BRAKING SYSTEM PROTECTION

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.

See Bendix publication BW5057 "Air Brake Handbook."

ROADSIDE INSPECTION

In the event of a roadside inspection the system behavior will be as follows: When the system is charged to governor cut-out and then one reservoir drain valve is opened, initially both reservoir gauges will fall; however, the Bendix AD-IS air dryer primary and secondary pressure protection valves will close at pressures above 70 psi, protecting the remaining brake circuit from further loss of pressure.

TEMPORARY AIR DRYER AND RESERVOIR SYSTEM BYPASS

To temporarily bypass the air dryer, follow these procedures:

Adhere to the General Safety Guidelines outlined elsewhere in this document.

Make sure that all residual pressure has been released and the air dryer purge reservoir has been drained to 0 psi, then remove the air supply line from the compressor to the inlet port (1/IN). Remove the safety valve from the Bendix AD-IS air dryer (see Figure 1 for location). Note that a short puff of trapped air may vent from the safety valve port when removing the valve. Install a T-fitting into the port. Using any adapters necessary, reinstall the safety valve in one of the branches of the T-fitting. Using any adapters necessary, install the air supply line into the remaining T-fitting port. After testing the T-fitting for any air leakage—by using a soap solution after charging to system cut-out pressure (a 1” bubble in 10 seconds is acceptable)—the vehicle may be returned to temporary service.

Note: This is a temporary bypass of the air dryer. Full repair of the unit must be carried out at the earliest opportunity.

With the air dryer removed from the system, contaminants will be entering the air brake system: reservoirs will need to be manually drained daily until the repairs are completed. At the end of each working day, park the vehicle and slowly

Maintenance Kits

Kit Description	Piece No.
Delivery Check Valve Replacement Kit	5004052
Desiccant Cartridge Replacement Kit (Standard)	5008414
Desiccant Cartridge Replacement Kit - Bendix® AD-IS®
PuraGuard® air dryer (can be used to replace the standard	5008414PG
cartridge)
Drain Valve	5004961N
Governor and Check Valve Replacement Kit	5004049
Governor Gasket	5007834
Heater & Thermostat Replacement (12 volt)	109495
Heater & Thermostat Replacement (24 volt)	109496
Bendix® PuraGuard® Oil Coalescing Desiccant Cartridge	K020366
Service New Kit
Mounting Bolt Kit	5009233
Protective Boots (for pressure protection valves)	5005163
Safety Valve	800350
Splash Shield Kit (includes bracket and cover)	K052469
Splash Shield Cover	5005266N
Silencer Kit	K021189
Wiring Harness & Splice Kit	109871N

Purge Valve Assembly Type	Configuration	Service Kit
		Pc. No.
	Bendix® AD-IS®Air Dryer	K022105
Purge Valve Assembly for	AD-IS®EverFlow®	K031560
climate conditions above	Module
-40°C (-40°F)
	AD-IS®Discharge Line	K031562
	Unloader
Arctic Purge Valve Assembly	AD-IS®Air Dryer	K031559
	AD-IS®EverFlow®
for climate conditions of		K031561
	Module
-40°C to -50°C
	AD-IS®Discharge Line
(-40°F to -58°F)		K031563
	Unloader

drain pressure through the drain valves—leave open to the atmosphere—for several hours, if possible. When repairs are carried out, be sure to check that all reservoirs (including the air dryer purge reservoir) are emptied of all contaminants.

If, after bypassing the air dryer and reservoir system, the system pressure still does not build, use the following procedure to remove, clean, and reinstall the delivery check valve.

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