Remove/check/install front axle brake pads - AR42.10-P-1600MCU

MODEL 451.3/4 

Fig 1: Identifying Front Axle Brake Pads Remove/Install Components (1 Of 2)

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Front Axle Brake Pads Remove/Install Components (2 Of 2)

Courtesy of MERCEDES-BENZ USA

	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		AH42.50-P-0001-01A
	Notes on repairs to brake system		AH42.00-P-0003-01A
1	Remove left or right front wheel		AR40.10-P-1100MCU
2	Counterhold upper guide pin (4) using a suitable open end wrench and unscrew bolt (2) on brake caliper (1)	Replace self-locking bolt (2).	*BA42.10-P-1001-10A
3	Fold brake caliper (1) downwards and remove brake pads (6)	After removing the brake pads (6) ensure that the brake pedal is no longer operated otherwise the brake piston (8) will be pressed out of the brake caliper (1). Observe installation position of brake pad (6) with wear indicator (9). : When folding up the brake caliper (1) ensure that the springs (3) of the brake pads (6) are clamped under the brake caliper (1).
4	Press back the brake piston (8) using the brake piston pusher tool (10)	When the brake piston (8) is pushed back the fluid level in the brake fluid reservoir rises. Ensure that the brake fluid reservoir does not overflow. It must be possible to move the brake piston (8) easily. Brake piston resetting device	Fig 4
5	Clean contact surfaces (arrows) on the brake pads (6) and brake caliper support (5) and coat with grease	No grease may come into contact with the friction surfaces of the brake pads (6) and brake disk, otherwise the braking effect will be impaired. Molykote 111 grease	*BR00.45-Z-1070-06A
	Checking
6	Check dust boot (7) for leaktightness	If dust boot (7) is damaged, the brake caliper (1) has to be replaced. See: ↓ Remove/install front axle brake caliper (1).	AR42.10-P-0070MCU
7	Check wear and condition of brake pads (6) as well as the brake disks	Brake pad thickness	*BE42.10-P-1001-05E
		Brake disk thickness	*BE42.10-P-1001-08E
		Vernier caliper	Figure
8	Check guide pin (4) ease of movement.	If the guide pins (4) get hooked or if they are sluggish, the brake caliper (1) has to be replaced. See: ↓ Remove/install front axle brake caliper (1).	AR42.10-P-0070MCU
9	Check bellows (11) for damage	Damaged bellows (11) should be replaced. : Twist the respective boot (11) with the fingers in order to ensure that sealing lip (12) seats correctly in the slot on the corresponding guide pin (4).
10	Install in the reverse order
	Risk of accident  when commissioning the vehicle due to a lack of braking effect when the service brake is operated for the first time after repair work	Before starting engine, actuate brake pedal several times until the pressure is built up and maintained in the brake system.	AS42.50-Z-0002-01A
11	Depress the brake pedal several times until the brake pads (6) contact the brake disk	A firm resistance must be noticeable at the brake pedal.
12	Check brake system for leaks		AR42.10-P-0100-01MCC

CHECK VALUES FOR FRONT BRAKE PAD

Number	Designation			Model 451.3/4
BE42.10-P-1001-05E	Brake pad thickness	New (with pad backing plate)	mm	15
		Wear limit (without pad backing plate) for maintenance service	mm	≤ 2
		Wear limit (with pad backing plate) for maintenance service	mm	≤ 7, 7
		Response of wear indicator (with pad backing plate)	mm	≈ 7, 7

TEST VALUES FOR FRONT BRAKE DISKS

Number	Designation			Model 451.3/4
BE42.10-P-1001-08E	Brake disk thickness	New	mm	9, 7
		Wear limit	mm	8

FRONT AXLE FLOATING CALIPER

Number	Designation		Model 451.3/4
BA42.10-P-1001-10A	Bolt, brake caliper to brake caliper support	Nm	30

Fig 3: Identifying Vernier Caliper (450 589 01 19 00)

Courtesy of MERCEDES-BENZ USA

Fig 4: Identifying Brake Piston Resetting Device (450 589 02 37 00)

Courtesy of MERCEDES-BENZ USA

REPAIR MATERIALS

Number	Designation	Order number
BR00.45-Z-1070-06A	Molykote 111 grease	Q0014759V000000000