BENDIX SD-08-2412 manual At the air dryer and plug the end of the air line leading to

Bendix® AD-9®AND AD-9®IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS	CAUSE	REMEDY
1. Dryer is constantly “cycling”	A. Excessive system leakage.	1. Test fittings, hoses, lines and connections. Apply soap solution
or purging. Dryer purges	IMPORTANT: Note whether air	to detect excessive leakage. Tighten or replace as needed
frequently (every 4 minutes	pressure loss is shown on dash	then repeat the air dryer charge-purge cycle and observe the
or less while vehicle is idling)	gauge(s). Pressure loss shown on	gauge installed in the supply reservoir. If leakage is within limits,
(continued).	gauges is caused by service brake	remove gauge from reservoir and replace drain cock or valve. If
	system or component leakage.	excessive leakage is detected, continue testing.
	Pressure loss NOT SHOWN	2. Test accessories connected to supply reservoir. Drain all
	on gauges is caused by supply	air pressure from system, disconnect all air lines leading to
	system or component leakage.	accessories (fan clutch, wipers, air seats, etc.) and plug the
	(continued)	reservoir at disconnection point. Build air system pressure until
		air dryer purges and observe supply reservoir gauge. If leakage
		is no longer excessive, repair or replace leaking accessory. If
		excessive leakage is detected, continue testing.
		3. Test governor leakage. Build system pressure to governor cut-
		out, turn off engine and apply soap solution to governor exhaust
		port and around cap. Leakage should not exceed a 1 in. bubble
		in 5 seconds. Reduce system pressure to 80 psi or less, and re-
		apply soap solution. Leakage should not exceed a 1 in. bubble in
		5 seconds. If excessive leakage is detected in either test, repair
		or replace governor.
		4. Test compressor unloader leakage. Drain all air pressure
		from system and remove the governor from the compressor.
		Temporarily plug the governor unloader port or air line that
		mated with, or connected to, the compressor. Build air system
		pressure until air dryer purges then IMMEDIATELY SHUT OFF
		THE ENGINE. Observe the air gauge in the supply reservoir. If
		leakage is within limits, replace the compressor unloaders. Re-
		connect the governor to the compressor (after removing plug
		installed in governor) and retest while observing supply reservoir
		gauge. If excessive leakage is detected, continue testing.
		5. Test air dryer purge valve and outlet (delivery) check valve. Drain
		all air pressure from system, remove the control line connection
		at the air dryer and plug the end of the air line leading to the
		governor (not the air dryer control port). Build system pressure
		to governor cut-out and observe air gauge. If little or no pressure
		drop is observed replace the air dryer check valve. If pressure
		drop continues, apply soap solution to air dryer purge exhaust
		and purge control port (where the control line was removed).
		Leakage should not exceed a 1 in. bubble in 5 seconds. If
		leakage is excessive, repair or replace purge valve assembly.

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