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

MODEL 171.442/ 454

Fig 1: Identifying Front Axle Brake Pads Components

Courtesy of MERCEDES-BENZ USA

MODIFICATION NOTES

25.10.04

Tightening torque of guide bolt, floating brake caliper to brake caliper support revised from 35 Nm to 25 Nm.

Model 171 only

	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.	-
	Risk of injury to skin and eyes caused by handling hot or glowing objects.	Wear safety gloves, protective clothing and safety glasses, if necessary.	-
	Notes on repairs to brake system		AH42.00-P-0003-01A
	Brake fluid notes		AH42.50-P-0001-01A
1	Open engine hood		AR88.40-P-1000V
2	Unscrew the cap on the brake fluid expansion reservoir and suction off some brake fluid	In order to prevent the expansion reservoir overflowing when pressing back the brake pistons (47)
3	Remove the front wheels
	Remove/install wheels, rotate if necessary		AP40.10-P-4050V
	Checking
4	Check brake pad thickness and brake disks (61)	Replace brake pads (43) and brake disks (61) in complete sets if necessary.
	Inspect condition of brake disks		AP42.10-P-4258V
	Check brake lining thickness	If the brake pads (43) are worn beyond the wear limit the web between the sealing groove and boot (47a) may be damaged, therefore: ↓	AP42.10-P-4253A
		Inspect brake system for leaks with pressure tester.	AR42.10-P-0015V
5	Disconnect electrical connector from right front brake pad contact sensor (S10/2)
6	Remove front axle brake caliper (31)	Do not detach brake hose (51), instead attach brake caliper (31) to vehicle so that it is free of tension. Do not kink or tension brake hose (51), as otherwise it will be damaged.	AR42.10-P-0070V
			*BA42.10-P-1003-10P
7	Remove brake pads (43) from brake carrier (31n)	Brake pads (43) are to be disposed of as special waste. The local authorities can provide information regarding whether disposal is also permitted as industrial waste similar to domestic waste. Installation: Only sets of brake pads (43) approved by Mercedes-Benz may be installed. Observe the installation position of the inner brake pads (43). The printed-on arrow must point in the direction of rotation of the wheel when driving forwards.
8	Pull the right front brake pad contact sensor (S10/2) out of the pad backing plate of the right inner brake pad (43)	Replace damaged or defective contact sensor (S10/2).
	Notes on installing brake pad wear sensor contact sensors		AH42.10-P-0003-01A
	Checking
9	Check boot (47a) of brake piston (47)	Check boot (47a) for damage and correct seat, if necessary: ↓
		Replace brake caliper (31).	AR42.10-P-0070V
10	Check boots (45a) and guide pins (45)	Check boots (45a) for damage and correct seat as well as guide bolts (45) for ease of movement, if necessary: ↓
		Replace brake caliper (31).	AR42.10-P-0070V
11	Press back brake piston (47) using resetting device (031)	If brake pads (43) have been removed from several brake calipers (31), the brake pistons (47) must be secured beforehand with wedges to prevent them from falling out . If the brake piston (47) is difficult to move: ↓
		Replace brake caliper (31).	AR42.10-P-0070V
			Fig 2
			Fig 3
	Clean
12	Clean contact surfaces of brake pads (43) on brake carrier (31n) and brake caliper (31) using brake caliper brush	In the process do not damage boots (45a, 47a). Installation: Ensure that the retaining plates (31d) are put on the brake carrier (31n) correctly.
			Fig 4
13	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.	-
14	Press the brake pedal several times until the brake pads (43) contact the brake disks (61)	Firm resistance should be noticeable at the brake pedal.
	Checking
15	Inspect fluid level in expansion reservoir, adjust to correct level if necessary
	Brake system - inspect fluid level		AP42.10-P-4210V
16	Carry out brake test on the test stand
	Brake testing on test stand		AP42.00-P-4290V