Disassembly and assembly of the B2 multi-disc brake (Mercedes-Benz S-Class W140)

Disassembly

Disassembly and assembly of the B2 multi-disc brake
14a - Brake outer support B2 or piston B3; 14b-d - Brake sealing rings B3; 27 - Brake piston B2; 28 - Piston guide ring; 28a-b - Sealing rings on piston guide ring; 29, 134b - Disc springs; 30 - Spring plate; 31, 134a - Retaining rings; 32 - Brake piston guide B2 and B3; 32a - Sealing ring; 134 - Disk block

Disassembly and assembly of the B2 multi-disc brake
31 - Retaining ring; 074 - Puller

1. Remove the retaining ring (134a).

2. Remove the brake disc assembly B2 (134) and disc spring (134b) from the outer brake support B2.

3. Place the puller (074) on the disc spring (29) and compress it until the groove for the snap ring is released.

4. Remove the retaining ring (31).

5. Remove the spring plate (30) and disc spring (29).

Disassembly and assembly of the B2 multi-disc brake
27 — Piston
28 — Piston guide ring
137 — Valve

1. Disconnect the piston guide ring (28) and the brake piston B2 (27) from the piston B3 (14a) by applying compressed air to the hole (D).

2. Press out the guide ring (28) from piston B2 (27).

Disassembly and assembly of the B2 multi-disc brake
A - Oil channel of piston B3; B - Oil channel of piston B2 from the back side; C - Clutch oil channel K3; D - Oil channel of piston B2 on the gearshift side

Remove the guide (32) from piston B3 (14a) by applying compressed air to the hole (A).

Assembly

Assembly of piston guide and outer support of multi-disc brake B2
2 - Transmission housing; 14a - Outer brake support B2, (piston B3); 32 - Piston guide

1. Set the guide (32) and piston B3 (14a) in the correct position. To do this, insert the guide (32) into the transmission housing (2) and tighten. Press the outer brake support B2 (14a) until it stops in the guide (32). The recess on the splines or the cutout on the outer brake support B2 (14a) must point downwards (arrow).

2. Insert the B2 brake piston (27) into the B3 brake piston (14a). The rounded ends of the sealing rings (14c), (28a) and (28b) must face outward. The rounded end of the sealing ring (14d) must face inward.

3. Insert the piston guide ring (28). The valve (137) in the piston guide ring must be on top.

4. Insert the disc spring (29) and spring plate (30).

5. Place the puller (074) on the disc spring (29) and compress it until the groove for the snap ring is released.

6. Insert the retaining ring (31).

7. Insert the disc spring (134b) and disc block (134) onto the outer brake support B2.

Section of the Brake B1
14a - Outer brake support B2; 27 - Piston B2; 134a - Outer disk (6.5 mm thick); 134b - Outer disk (1.8 mm thick); 134c - Outer disk (1.8 mm thick); 134d - Friction discs; 134e - Disc spring; 144a - Retaining ring; L - Gap

1. Install the B3 B3 brake discs together in the order shown in the accompanying illustration and insert them one by one.

2. Install the press (078) on the outer disk (70c).

3. Compress the disc block with a press until the stop until the marking ring is visible (small arrow).

4. Measure the clearance "L" at three points between the retaining ring (144a) and the outer disc (134a). The clearance values in the multi-disc brake (82) are shown in the table below.

5. If necessary, adjust the clearance by selecting a retaining ring (144a) of the required thickness. Rings are available in thicknesses of 2.9, 3.2, 3.5, 3.8 and 4.1 mm.

6. Install the retaining ring (134a).