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

MODEL 215, 220

Shows model 220

Fig 1: Identifying Checking Brake Booster (Shows Model 220)

Courtesy of MERCEDES-BENZ USA

MODIFICATION NOTES

11.8.05

Bleed screw on rear axle fixed brake caliper

Model 215.379

	Checking
1	Operate brake pedal several times until vacuum in brake booster (16) is reduced
2	Connect testing unit (030) to brake booster	Measuring connection (031) for checking check valve (17) or brake booster (16).	AR43.10-P-0024-01I
		Vacuum tester	Figure
		Test connection	Figure
		Test values for brake booster	*BE43.10-P-1001-01A
		Test values for brake booster	*BE43.10-P-1002-01A
3	Connect pressure tester (051) with connection fitting to brake caliper	Pressure tester After testing, only bleed the brake caliper to which the pressure tester was connected.
		Front axle bleed screw	*BA42.10-P-1002-10G
		Rear axle bleed screw	*BA42.10-P-1002-12G
4	Connect pedal force measuring instrument (060) at brake pedal	Pedal force meter
5	Start engine and create a vacuum of 0.75 to 0.80 bar by accelerating and then suddenly releasing the accelerator pedal	If the vacuum is considerably lower or if the vacuum drops immediately, the O-ring between the brake booster and master brake cylinder may be damaged or the non-return valve in the vacuum line may be defective: ↓
		Checking check valve	AR43.10-P-0023I
		Remove/install master brake cylinder, install new O-ring	AR42.10-P-0300I
6	Apply specified force to the brake pedal and read line pressure	To cover measurement errors as far as possible (wrong force on brake pedal, wrong vacuum) and measurement scatter of the gauges, a tolerance of ± 10 bar on the specified value is permissible. The measured value must be within the value range.	*BE43.10-P-1003-01A
7	Disconnect testing unit (030) from brake booster	Vacuum tester	Figure
7	Disconnect testing unit (030) from brake booster	Test connection	Figure
8	Disconnect pressure tester (051) with connection fitting from brake caliper	Pressure tester
8		Test connection	Figure
9	Remove pedal force meter (060) from brake pedal
10	Bleed brake system	Pedal force meter

PNEUMATIC BRAKE BOOSTER TEST SPECIFICATIONS

Number	Designation					Model 215	Model 220
BE43.10-P-1001-01A	Brake booster dia.			-	mm	203/228, 6	203/228, 6
BE43.10-P-1001-01A	Brake booster dia.			-	inch	8/9	8/9
BE43.10-P-1002-01A	Boost factor					≈6, 3	≈6, 3
BE43.10-P-1003-01A	Brake pipe line pressure	Intake pipe vacuum	Force on brake pedal	50 N	bar	22...30	22...30
		0.75...0.8 bar		100 N	bar	42...52	42...52
				150 N	bar	60...70	60...70
				200 N	bar	80...95	80...95
				250 N	bar	100...120	100...120

FRONT AXLE BRAKE CALIPER

Number	Designation		Model 215
BA42.10-P-1002-10G	Bleed screw to brake caliper	Nm	7

REAR AXLE BRAKE CALIPER

Number	Designation		Model 215 except 215.374	Model 215.374
BA42.10-P-1002-12G	Bleed screw to brake caliper	Nm	7	14

Fig 2: Identifying Vacuum Tester (201 589 13 21 00)

Courtesy of MERCEDES-BENZ USA

Fig 3: Identifying Test Connection (168 589 08 63 00)

Courtesy of MERCEDES-BENZ USA