Humming/droning noise when SBC system loads - AF42.46-P-1101A

MODEL 211, 219

MODIFICATION NOTES

19.1.06

Changeover to suction hose with dual suction damper, the single suction damper (000 431 04 77) is no longer available

OPERATION NO. OF OPERATION TEXTS OR STANDARD TEXTS AND FLAT RATES

Category	Op. no.	Operation text
P	023818	Operation: Install pulsation damper into suction hose of hydraulic unit (SBC)

Damage code	Cause	Remedy
43 102 36	Noises emitted when the pump is running are transmitted to the passenger compartment during the charging process of the SBC system.	0 All linked operations are included in the times allowed for the main operation item, i.e. completely bleeding the brake system using STAR DIAGNOSIS is included.
	Humming/droning noise during the charging process of the SBC system, possibly in connection with vibrations at the brake pedal.	Installation of a dual pulsation damper in the suction hose.
		Work on the SBC system may only be carried out by trained personnel.	SI42.46-P-0001D
		1 Deactivate SBC using STAR DIAGNOSIS
		2 Suction off brake fluid completely from the reservoir.
		For pulling the suction hose off the suction line do not use screwdrivers or similar sharp-edged tools as the suction line at the vehicle end is damaged in the process and a faultless function of the SBC brake system is no longer guaranteed.
		3 Pull the suction hose off the fitting of the SBC hydraulic unit.
			Fig 2
		For pulling the suction hose off the suction line do not use screwdrivers or similar sharp-edged tools as the suction line at the vehicle end is damaged in the process and a faultless function of the SBC brake system is no longer guaranteed. 4 Replace the suction hose (1) completely, to do this: Loosen the clamp at the transition of the suction hose to the suction line (arrow). Pull the suction hose carefully off the suction line.
			Fig 2
		The suction hose which has been removed is no longer required
		5 Push the new suction hose onto the suction line at the vehicle end and secure with a new clamp. It is essential to use a new clamp.
		6 Check for leaks at the hose connections. Even the smallest drops of brake fluid are a sign of leakage! Over 5 min allow the maximum filling pressure of the filling unit (2.5 - 3.0 bar) to be applied to the brake fluid reservoir and then check the suction line for visible leakage at the interfaces.
		7 Bleed SBC system using STAR DIAGNOSIS.

Fig 1: Identifying Suction Hose

Fig 2: Identifying Wedge Tool (110 589 03 59 00)

PARTS ORDERING NOTES

Part no.	Designation	Quantity
A 211 420 72 26	Suction hose, for right-hand drive vehicles only	1
A 211 420 88 26/05	Suction hose, for left-hand drive vehicles only	1
A 005 997 19 90	Hose clamp	2