Checking Brake Booster - AR43.10-P-0325GZ

MODEL 164, 166, 292 

Shown on model 164.175 

	Risk of poisoning  from swallowing brake fluid. Risk of injury  from skin and eye contact with brake fluid	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 injury  . Skin or eye injuries may result when handling hot or glowing objects.	Wear protective gloves, protective clothing and safety glasses, if necessary.	AS00.00-Z-0002-01A
	Brake fluid notes		AH42.50-P-0001-01A
	Notes on repairs to brake system		AH42.00-P-0003-01A
	Check
1	Open engine hood and raise to vertical position	Model 164	AR88.40-P-1000GZ
		Model 166	AR88.40-P-1000GQ
2	Remove cover over left suspension strut tower	Model 166, 292
3	Clean area surrounding cap on brake fluid reservoir
4	Connect vacuum tester (1) and test connection (8) to BAS brake booster (A7/7)	Pay attention to manufacturer's operating instructions. Otherwise measurement errors can occur.	AR43.10-P-0024-01GZ
		Test connection	Figure
		Vacuum tester	Figure
5	Unscrew cap on brake fluid reservoir and connect filling and bleeding unit 000 588 01 82 00 Filling unit	Note operating instructions for filler/bleeder unit.	WS25.00-P-0016B
6	Detach left front wheel-and-tire assy	Model 164	AP40.10-P-4050Z
		Model 166	AP40.10-P-4050EW
		Model 292	AR40.10-P-1100GQC
7	Remove bleed screw from brake caliper (7)
8	Connect test equipment (6) to brake caliper (7)
	000 588 07 21 00 Test equipment		WS42.00-P-0014B
		Test equipment (6) for hydraulic oil systems may not be used for systems with brake fluid. Otherwise, the brake fluid will be mixed with mineral oil. This results in brake failure. Pay attention to manufacturer's operating instructions. Otherwise, incorrect operation and measurement error can occur.
9	Bleed test equipment (6)
10	Switch off filling and bleeding unit and vent pressure from brake fluid reservoir
11	Mount pedal force meter
	000 588 05 21 00 Roller brake test stand		WS42.00-P-0006B
		Pay attention to manufacturer's operating instructions. Otherwise measurement errors can occur. Mount sensor (4) of pedal force meter to brake pedal and position display unit (5) in field of vision.
12	Risk of accident  from vehicle starting off by itself when engine running. Risk of injury  (bruises and burns) resulting from working on the engine while it is being started or when it is running. Suddenly release accelerator pedal at medium engine rpm to generate a vacuum in the BAS brake booster (A7/7)	Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts. If only a significantly lower vacuum than 0.75 to 0.80 bar is reached or if the vacuum drops immediately, the O-ring between the BAS brake booster (A7/7) and the master brake cylinder or the vacuum line or the check valve (2) may be defective. If complaint present ↓	AS00.00-Z-0005-01A
		Checking check valve	AR43.10-P-0023GZ
		Remove brake master cylinder	AR42.10-P-0310GZ
13	Operate brake pedal with five specified pedal forces in succession	Brake line pressure	*BE43.10-P-1002-01E
14	Read off and note down the corresponding measurements for the brake line pressure of the low pressure or high pressure manometer of the pressure gauge (6).	Measured values must be within specified ranges. With each measurement, ensure that the vacuum of 0.75 to 0.80 bar is maintained.
15	Turn off engine
16	Detach pedal force meter
17	Detach testing unit (6) 000 588 07 21 00 Test equipment		WS42.00-P-0014B
18	Screw in bleed screw
19	Bleed brake system	Bleed left front brake caliper (7) only. Model 164	AR42.10-P-0010GZ
		Model 166, 292	AR42.10-P-0010CW
20	Mount left front wheel-and-tire assy	Model 164	AP40.10-P-4050Z
		Model 166	AP40.10-P-4050EW
		Model 292	AR40.10-P-1100GQC
21	Detach filler/bleeder unit and seal brake fluid reservoir using cap 000 588 01 82 00 Filling unit	Note operating instructions for filler/bleeder unit.	WS25.00-P-0016B
22	Detach vacuum tester (1) and test connection (8)		AR43.10-P-0024-01GZ
		Test connection	Figure
		Vacuum tester	Figure
23	Install cover over left suspension strut tower	Model 166, 292
24	Close engine hood	Model 164	AR88.40-P-1000GZ
		Model 166	AR88.40-P-1000GQ

Fig 1: Identifying Vacuum Tester (201 589 13 21 00)

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Test Connection (168 589 08 63 00)

Courtesy of MERCEDES-BENZ USA