Test brake system with pressure tester for leaks - AR42.10-P-0015RT

MODEL 251 

Fig 1: Testing Brake System With Pressure Tester For Leaks - Shown On Left Front Wheel Brake

Courtesy of MERCEDES-BENZ USA

Shown on the left front wheel brake 

Fig 2: Testing Brake System With Pressure Tester For Leaks

Courtesy of MERCEDES-BENZ USA

Fig 3: Pressure Test On Rear Wheel Brake Connection Diagram

Courtesy of MERCEDES-BENZ USA

Connection diagram and accessories required for pressure test on rear wheel brake 

	Checking
	Risk of poisoning  caused by swallowing brake fluid. Risk of injury  caused by brake fluid coming into contact with skin and eyes.	Only pour brake fluid into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.	AS42.50-Z-0001-01A
	Risk of death  caused by vehicle slipping or toppling off of the lifting platform.	Align vehicle between columns of vehicle lift and position four support plates at vehicle lift support points specified by vehicle manufacturer.	AS00.00-Z-0010-01A
	Brake fluid notes	All models	AH42.50-P-0001-01A
	Notes on externally invisible brake fluid loss		AH42.10-P-9406-02RT
	Notes on repairs to brake system	All models	AH42.00-P-0003-01A
1	Open engine hood and raise to vertical position		AR88.40-P-1000RT
2	Connect brake fluid replacement unit	Observe manufacturer's operating instructions! Brake fluid change unit
3	Raise vehicle using two-post lift	Half the height. Two-post lifting platform 3.0-3.5 t, electromechanical	AR00.60-P-1000RT
4.1	Remove left front wheel or right front wheel	When testing the brake line pressure at the front wheel brake.
	Remove/install wheels, rotate if necessary		AP40.10-P-4050RT
5	Remove bleed screw on a floating brake caliper (2) of the brake circuit to be tested and connect pressure tester (3)	Pressure testers for hydraulic oil systems must not be used for systems with brake fluid otherwise brake fluid is mixed with mineral oil which can cause the brakes to fail! Observe manufacturer's operating instructions in order to prevent erroneous measurement or faulty operation! At the rear wheel brake  a banjo union (11), a banjo bolt (9) as well as three gaskets (10) are to be used for adaptation. The banjo union (11) is to be mounted at the pressure tester connection (12) with a gasket. Then remove the bleed screw (8) from the corresponding floating brake caliper (2) of the rear wheel brake. Attach the banjo union (11) together with the banjo bolt (9) and the two seals (10) to the floating brake caliper (2) instead of the bleed screw (8). The banjo union (11) as well as the banjo bolt (9) are to be obtained from the manufacturer of the recommended pressure tester (3)  (see the manufacturer's information enclosed with the pressure tester (3)). An assortment of seals (10) is already supplied with the pressure tester (3) ATE part number of banjo bolt (9): 03.3520-0300.1 ATE part number of banjo union (11): 03.3521-0100.1 Collect escaping brake fluid. Pressure tester
6	Bleed pressure tester (3) with brake fluid replacement unit	Observe manufacturer's operating instructions in order to prevent erroneous measurement or faulty operation! Pressure tester Brake fluid change unit
7	Switch off brake fluid replacement unit and release pressure	Brake fluid change unit
	High-pressure check
8	Allow the engine to run at moderate speed in neutral and by jerkily releasing the accelerator pedal, produce as high a vacuum as possible in the brake booster.
9	Depress the brake pedal (5) as far as possible immediately, then insert the brake pedal jack (4) and tension as far as possible by means of the knob (1). After a short dwell time of a few seconds, read off and note the measured value of the brake line pressure from high pressure gauge of the pressure tester (3)	Observe manufacturer's operating instructions in order to prevent erroneous measurement or faulty operation! Only use the brake pedal jack (4) in combination with the adapter for the brake pedal jack (6). Insert the brake pedal jack (4) so that its rubber mounting is supported on the driver seat frame (7) as shown. If the brake pedal jack (4) is inserted differently, there is the danger of damaging components and erroneous measurements occurring on the brake line pressure test Duration of high pressure test:  5 min. Throughout the 5 min. duration of the test, the brake line pressure decrease must not amount to more than 5% of the measurement which was read off and noted down at the beginning.
		Brake pedal winch	Fig 4
		Adapter for brake pedal jack Pressure tester	Fig 5
	Low-pressure testing
10	Switch off the engine and release the brake pedal jack (4). Then operate the brake pedal (5) several times until the vacuum in the brake booster is reduced	Brake pedal winch	Fig 4
		Adapter for brake pedal jack	Fig 5
11	Press down the brake pedal (5) as far as possible and insert the brake pedal jack (4). Then turn back at the knob (1) slowly until a brake line pressure of approx. 3 bar is displayed on the low pressure gauge of the pressure tester (3)	Observe manufacturer's operating instructions in order to prevent erroneous measurement or faulty operation! Only use the brake pedal jack (4) in combination with the adapter for the brake pedal jack (6). Insert the brake pedal jack (4) so that its rubber mounting is supported on the driver seat frame (7) as shown. If the brake pedal jack (4) is inserted differently, there is the danger of damaging components and erroneous measurements occurring on the brake line pressure test Duration of low pressure test:  2 min. The previously set brake line pressure must not fall throughout the 2 min. duration of the test
		Brake pedal winch	Fig 4
		Adapter for brake pedal jack Pressure tester	Fig 5
12	Release and remove brake pedal jack (4)	Brake pedal winch	Fig 4
		Adapter for brake pedal jack	Fig 5
13	Detach pressure tester (3) and screw the bleed screw (8) into the floating brake caliper (2) again	Collect escaping brake fluid. Pressure tester
14	Bleed brake system	After the brake line pressure test only bleed the floating brake caliper to which the pressure tester (3) was connected. Observe manufacturer's operating instructions!	AR42.10-P-0010RT
			*BA42.10-P-1001-10L
			*BA42.10-P-1001-12L
		Brake fluid change unit	*BF42.10-P-1001-01H
15.1	Mount left front wheel or right front wheel	If a brake line pressure test was carried out on the front wheel brake.
	Remove/install wheels, rotate if necessary		AP40.10-P-4050RT
16	Lower vehicle using two-post lift		AR00.60-P-1000RT
		Two-post lifting platform 3.0-3.5 t, electromechanical
17	Detach brake fluid replacement unit	Brake fluid change unit
18	Close engine hood		AR88.40-P-1000RT

Fig 4: Identifying Brake Pedal Jack (000 589 18 31 00)

Courtesy of MERCEDES-BENZ USA

Fig 5: Identifying Adapter For Brake Pedal Jack (211 589 00 31 00)

Courtesy of MERCEDES-BENZ USA