Checking brake booster - AR43.10-P-0325GZ

MODEL 164, 166

Shows model 164.175

Fig 1: Checking Brake Booster - Shows Model 164.175

Courtesy of MERCEDES-BENZ USA

MODIFICATION NOTES

1.7.11

Clean the area around the cap on the brake fluid reservoir, added

Operation step 3

	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 injury to skin and eyes caused by handling hot or glowing objects.	Wear safety 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
1	Open engine hood and raise to vertical position	Model 164	AR88.40-P-1000GZ
1	Open engine hood and raise to vertical position	Model 166	AR88.40-P-1000GQ
2	Remove cover over left suspension strut tower	Model 166
	Clean
3	Clean area surrounding cap on brake fluid reservoir	Cleaner from package	*BR00.45-Z-1028-04A
4	Connect vacuum tester (1) to BAS brake booster (A7/7)	Pay attention to manufacturer's operating instructions. Otherwise measurement errors can occur.	AR43.10-P-0024-01GZ
			Figure
			Figure
5	Unscrew cap on brake fluid reservoir and connect filling and bleeding unit	Note operating instructions for filler/bleeder unit. Brake fluid changer with reservoir (10-20 l)
6	Detach left front wheel-and-tire assy	Model 164	AP40.10-P-4050Z
6	Detach left front wheel-and-tire assy	Model 166	AP40.10-P-4050EW
7	Remove bleed screw at brake caliper (7) and connect pressure tester (6)	Pressure testers (6) for hydraulic fluid systems must 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! Collect escaping brake fluid. Pressure tester
8	Bleed pressure tester (6)
9	Switch off filling and bleeding unit and vent pressure from brake fluid reservoir
10	Mount pedal force meter	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. Pedal force meter
	Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near the engine as it is running	Secure vehicle to prevent it from moving by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.	AS00.00-Z-0005-01A
11	Generate vacuum in BAS brake booster (A7/7)	To do so, abruptly release accelerator pedal at medium engine speed. 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 master brake cylinder or the vacuum line or the check valve (2) may be defect: ↓
		Check the check valve (2).	AR43.10-P-0023GZ
		Remove tandem master brake cylinder.	AR42.10-P-0310GZ
12	Operate brake pedal with five specified pedal forces in succession	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.	*BE43.10-P-1002-01E
13	Turn off engine
14	Detach pedal force meter
15	Detach pressure gauge (6) and screw in bleed screw	Collect escaping brake fluid.
16	Bleed brake system	Bleed left front brake caliper (7) only.
		Model 164	AR42.10-P-0010GZ
		Model 166	AR42.10-P-0010CW
17	Mount left front wheel-and-tire assy	Model 164	AP40.10-P-4050Z
17	Mount left front wheel-and-tire assy	Model 166	AP40.10-P-4050EW
18	Detach filler/bleeder unit and seal brake fluid reservoir using cap	Note operating instructions for filler/bleeder unit.
19	Detach vacuum tester (1)		AR43.10-P-0024-01GZ
20	Install cover over left suspension strut tower	Model 166
21	Close engine hood	Model 164	AR88.40-P-1000GZ
21	Close engine hood	Model 166	AR88.40-P-1000GQ

PNEUMATIC BRAKE BOOSTER TEST SPECIFICATIONS

Number	Designation					Model 164.1/8
BE43.10-P-1002-01E	Brake pipe line pressure	Intake manifold vacuum	Force on brake pedal	50 N	bar	26.5...32.5
		0.75...0.8 bar		100 N	bar	50...57
				150 N	bar	72...82
				200 N	bar	95...107
				250 N	bar	118...124

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

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Vacuum Tester (201 589 13 21 00)

Courtesy of MERCEDES-BENZ USA

REPAIR MATERIALS

Number	Designation	Order number
BR00.45-Z-1028-04A	Cleaner from package