Remove/install brakepads on floating brake caliper

AR42.10-P-0160RT

Remove/install brakepads on floating brake caliper

06.03.2020

Model

251

Modification notes

23.09.2008

"Apply brake paste" added

Operation step 15

Front axle

1

Spring steel sheet

3

Brake shoe

5

Pusher tool

2

Floating caliper

4

Protective cap

Rear axle

1

Spring steel sheet

3

Brake shoe

5

Pusher tool

2

Floating caliper

4

Protective cap

 

Remove/install

 Caution

Risk of poisoning from swallowing brake fluid. Risk of injury from skin and eye contact with brake fluid

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

 Warning

Risk of injury. Skin or eye injuries may result when handling hot or glowing objects.

Wear protective gloves, protective clothing and safety glasses, if necessary.

AS00.00-Z-0002-01A

Topical note

Brake fluid notes

AH42.50-P-0001-01A

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A

Topical note

Notes on self-locking nuts and bolts

AH00.00-N-0001-01A

1

Reduce fluid level in expansion reservoir for brake fluid down to "MIN" marking

 In order to prevent the expansion reservoir overflowing when pressing back the brake pistons.

2

Remove wheels



Remove/install wheels, rotate if necessary

AP40.10-P-4050RT

3

Disconnect electrical connection of brakepad contact sensor

Notes on installing brake wear indicator contact sensors

AH42.10-P-0003-01GZ

 Installation: When installing brake wear indicator contact sensors

4

Pry off spring steel sheet (1) and remove

5

Take off cover (4) and remove screws of guide pin

 Installation: Replace bolts.

 Guide pin to brake caliper support

*BA42.10-P-1002-10L

 Guide pin to brake caliper support

*BA42.10-P-1003-12L

6

Remove floating brake caliper (2) with brakepads (3)

Topical note

Notes on installing brake hoses

AH42.10-P-9406-01A


Do not tension or kink brake hose. To relieve the load on the brake hose, secure the floating brake caliper (2) to the vehicle free of tension.
Otherwise the brake hose will be damaged.
Check correct routing of brake hose.

7

Remove brakepads (3) from floating brake caliper (2)

 Brakepads (3) 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.

 Only brakepads (3) approved by Mercedes-Benz may be installed as a set.



Check

8

Check brakepad thickness and brake disks



Check brake lining thickness

AP42.10-P-4253A



Inspect condition of brake disks

AP42.10-P-4258GZ

 Replace brakepads (3) and brake disks as set only, if necessary.

9

Remove and check brakepad contact sensor from backing plate of brakepad (3)

Notes on installing brake wear indicator contact sensors

AH42.10-P-0003-01GZ

 Check for damage, replace contact sensor if necessary.

10

Check guide pins and boots

 Check guide pins for sluggishness and damage. Check boots for damage and loose seat. Replace damaged parts with new parts.

11

Check floating brake caliper (2)

If the floating brake caliper (2) is leaky or the dust boot is damaged:



Replace front axle brake caliper.

AR42.10-P-0070RT

Replace rear axle brake caliper.

AR42.10-P-0080RT

12

Press back brake piston using pusher tool (5)

If the brake piston is difficult to move:



Replace front axle brake caliper.

AR42.10-P-0070RT

Replace rear axle brake caliper.

AR42.10-P-0080RT

 Resetting device

*000589524300

13

Check folds of dust boot

 If the dust boot projects beyond the brake piston, position the dust boot correctly.



Clean

14

Clean contact surfaces of brakepads (3) on floating brake caliper (2) and floating caliper carrier with rag

 Installation:
Do not damage the dust boots and boots while doing so.
Do not use pointed or sharp-edged tools, in order to avoid damage.

Assembly cleaner

*BR00.45-Z-1028-04A

15

Apply brake paste

Apply brake pad paste to brake pads
Except model 251.077/177

AR42.10-P-0161-01B


Use only the brake paste listed in the linked description and apply this only at the points specified.
Otherwise, complaints may be made about the noise or damage can occur to the brake system!

MB Plastilube brake paste (brownish)

*BR00.45-Z-1084-06A

16

Install in the reverse order

 Danger

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 the engine, actuate brake pedal several times until pressure is built up and maintained in the brake system.

AS42.50-Z-0002-01A

17

Depress brake pedal several times until brakepads (3) rest against brake disks

 Firm resistance should be noticeable at the brake pedal.

18

Check brake fluid level; correct if necessary



Brake system - inspect fluid level

AP42.10-P-4210RT

 Front axle brake caliper

Number

Designation

Model 251 (except 251.077/177)

Model 251.077/177

BA42.10-P-1002-10L

Guide pin to brake caliper support

Nm

55

30

 Rear axle brake caliper

Number

Designation

Model 251

BA42.10-P-1003-12L

Guide pin to brake caliper support

Nm

25

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01

BR00.45-Z-1084-06A

MB Plastilube brake paste (brownish)

A 002 989 37 51