Remove/install brake booster - AR43.10-P-0350RT

MODEL 251 

Fig 1: Identifying Brake Booster Remove/Install Components (1 Of 2)

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Brake Booster Remove/Install Components (2 Of 2)

Courtesy of MERCEDES-BENZ USA

MODIFICATION NOTES

1.9.10

"Perform brake test on test bench" reference changed

Test sequence augmented/revised

	Remove/install
	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
	Brake fluid notes	All models	AH42.50-P-0001-01A
	Notes on repairs to brake system	All models	AH42.00-P-0003-01A
	Notes on externally invisible brake fluid loss		AH42.10-P-9406-02RT
1	Move wiper arms (4) into the final position
2	Move driver seat back
3	Switch off ignition and remove the transmitter key from the EIS [EZS] control unit	On vehicles with code 889 Keyless-Go: Press Keyless-Go start/stop button repeatedly until the ignition is switched off. Remove transmitter key from vehicle and store it in a location beyond its transmission range (at least 2 m).
4	Eliminate vacuum in BAS brake booster (A7/7)	Reduce vacuum by depressing the brake pedal several times.
5	Unlock engine hood	The engine hood can no longer be unlocked after removing the cover under the dashboard (left).
6	Remove left cover under the dashboard		AR68.10-P-1500RT
7	Remove securing clamp (1) and pull out pin (2).
8	Unscrew nuts (3) of BAS brake booster (A7/7)	Nut, brake booster carrier to front end	*BA43.10-P-1001-01H
9	Open engine hood and raise to vertical position		AR88.40-P-1000RT
10	Remove wiper arms (4)		AR82.30-P-6100RT
11	Remove water deflector (5) above the wiper system (6)		AR83.25-P-1406RT
12	Remove wiper system (6)		AR82.30-P-6400RT
		Bolt on wiper motor	*BA82.30-P-1002-01K
		Bolt for window wiper frame to body	*BA82.30-P-1004-01K
13	Remove partition wall between wheel well liners (7)		AR62.30-P-2400RT
		Bolt for partition wall between wheel well liners to wheel well liners	*BA62.30-P-1007-01E
14	Remove stepped tandem brake master cylinder		AR42.10-P-0310RT
		Brake pipe to master brake cylinder	*BA42.10-P-1003-14A
		Nut, brake master cylinder to brake booster	*BA42.10-P-1001-05I
		Bolt, impact deflector plate to master brake cylinder	*BA42.10-P-1002-05I
		Bolt, brake fluid reservoir to master brake cylinder	*BA42.10-P-1003-05I
		Brake pressure sensor to master brake cylinder	*BA42.45-P-1001-01K
		Box wrench bit	Fig 3
		Set of stop plugs	Fig 4
15	Remove alarm signal horn (H3)		AR80.50-P-9840RT
16	Disconnect vacuum line (8) from BAS brake booster (A7/7).
17	Disconnect release switch connector (9).
18	Detach diaphragm travel sensor connector (10)
19	Take out BAS brake booster (A7/7)	Do not damage boot when installing BAS brake booster (A7/7) as this will cause leaks. Install new gasket
20	Install in the reverse order
21	Bleed brake system		AR42.10-P-0010RT
		Front axle:
		Bleed screw to brake caliper Rear axle	*BA42.10-P-1001-10L
		Bleed screw to brake caliper	*BA42.10-P-1001-12L
		Brake fluid	*BF42.10-P-1001-01H
	Checking
	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
	Check brake system for leaks		AR42.10-P-0100-01RT
	Risk of death  caused by limbs being caught  or crushed  by rotating parts when performing tests on the brake test stand	Never leave the vehicle unattended on the rollers except in an emergency. Ensure that no one is under the vehicle or near rotating parts during testing. In case of emergency, use the EMERGENCY STOP switch to shut down test stand.	AS42.00-Z-0001-01A
23	Carry out brake test on the test stand		AP42.00-P-4290BA

BRAKE BOOSTER

Number	Designation		Model 251
BA43.10-P-1001-01H	Nut, brake booster carrier to front end	Nm	25

CROSSMEMBER AND FRONT REINFORCEMENT

Number	Designation		Model 251
BA62.30-P-1007-01E	Bolt for partition wall between wheel well liners to wheel well liners	Nm	23

WINDSHIELD WIPER

Number	Designation		Model 251
BA82.30-P-1002-01K	Bolt on wiper motor	Nm	10
BA82.30-P-1004-01K	Bolt for window wiper frame to body	Nm	20

BRAKE HOSES, BRAKE LINES

Number	Designation		Model 251
BA42.10-P-1003-14A	Brake pipe to master brake cylinder	Nm	18

MASTER BRAKE CYLINDER

Number	Designation		Model 251
BA42.10-P-1001-05I	Nut, brake master cylinder to brake booster	Nm	25
BA42.10-P-1002-05I	Bolt, impact deflector plate to master brake cylinder	Nm	14
BA42.10-P-1003-05I	Bolt, brake fluid reservoir to master brake cylinder	Nm	4

ELECTRONIC STABILITY PROGRAM (ESP)

Number	Designation		Model 251
BA42.45-P-1001-01K	Brake pressure sensor to master brake cylinder	Nm	35

FRONT AXLE BRAKE CALIPER

Number	Designation		Model 251 except 251.077/177	Model 251.077/177
BA42.10-P-1001-10L	Bleed screw to brake caliper	Nm	18	18

REAR AXLE BRAKE CALIPER

Number	Designation		Model 164	Model 251
BA42.10-P-1001-12L	Bleed screw to brake caliper	Nm	7	7

BRAKE FLUID

Number	Designation			Model 251
BF42.10-P-1001-01H	Brake fluid	Filling capacity	Liters	≈0, 8
		Specifications for Operating Fluids	Specification	DOT 4. See GENERAL BRAKE FLUID (https://bevo.mercedes-benz.com/index.php?language_id=1)
			Specification	MB 331.0 brake fluid A 000 989 08 07

Fig 3: Identifying Box Wrench Bit (140 589 00 03 00)

Courtesy of MERCEDES-BENZ USA

Fig 4: Identifying Set Of Stop Plugs (129 589 00 91 00)

Courtesy of MERCEDES-BENZ USA