Removing, checking and installing rear axle brake pads - AR42.10-P-1700V

MODEL 171.442 /454 /456 /473

Fig 1: Identifying Rear Axle Brake Pads Components

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.	-
	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 and raise to vertical position		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 the brake pistons (47) are pushed back.
3	Remove rear 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 sets if necessary.
	Inspect condition of brake disks		-
	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: ↓	-
		Check brake system for leaks with pressure tester.	AR42.10-P-0015V
5	Disconnect the right rear brake pad contact sensor connector (X88/15) and pull the right rear brake pad contact sensor (S10/4) out of the brake pad (43)	Type 171.456
		Installation: Replace defective right rear brake pad contact sensor (S10/4).
	Notes on installing brake pad wear sensor contact sensors		AH42.10-P-0003-01A
6	Hammer the retaining pin (41) out of the brake caliper (31) using a punch and remove spring (42)	Installation: The arrow embossed in the retaining spring (42) must point in the direction of rotation of the wheel when driving forwards. Installation: Hammer in retaining pin (41) as far as the stop in the brake caliper (31). Model 171.473 two retaining pins (41) are fitted in each brake caliper (31).
7	Using lever (034) pry brake pads (43) out of brake caliper (31)	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 the brake pads (43) approved by Mercedes-Benz may be built-in as a set.
			Figure
	Checking
8	Check boots (47a) of brake pistons (47)	Check boots (47a) for damage and correct position, if necessary: ↓ Replace brake caliper (31).
		Model 171.442 /454/ 456	AR42.10-P-0080V
		Model 171.473	-
9	Press back brake piston (47)	using resetting device (031) If brake pads (43) have been removed from several brake calipers (31), their brake pistons (47) must be secured beforehand with wedges to prevent them from falling out . Do not fit pusher tool (031) to the brake disk (61), but push back both brake pistons (47) of a brake caliper (31) simultaneously. If brake pistons (47) are sluggish: ↓ Replace brake caliper (31).
		Model 171.442 /454/ 456	AR42.10-P-0080V
		Model 171.473	-
			Figure
			Figure
	Clean
10	Clean guide of brake pads (43) using a brake caliper brush (030)	Do not damage boots (47a).
			Figure
11	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.	-
12	Press the brake pedal several times until the brake pads (43) contact the brake disks (61)	A firm resistance must be noticeable at the brake pedal.
	Checking
13	Inspect fluid level in expansion reservoir, adjust to correct level if necessary
	Brake system - inspect fluid level		AP42.10-P-4210V
14	Perform a function test
	Brake testing on test stand		AP42.00-P-4290V