MBE 900 – Section 7.2 Exhaust Brake Assembly

Section 7.2
Exhaust Brake Assembly

To increase braking performance, the engine can be equipped with an exhaust brake on the turbocharger in conjunction with constant-throttle valves on the cylinder head. The exhaust back-pressure is used by the exhaust brake to increase braking performance.‪

Section 7.2.1
Exhaust Brake Assembly Removal

Remove the exhaust brake assembly as follows:‪

1. Remove the four hex head bolts that fasten the heat shield to the exhaust brake valve housing and turbocharger. Remove the heat shield. See Figure "Exhaust Brake Assembly Removal, 4-Cylinder Engines" for the 4-cylinder engine and Figure "Exhaust Brake Assembly Removal, 6-Cylinder Engines" for the 6-cylinder engine.
   

   1. Exhaust Brake Valve Housing‪	4. Exhaust Brake Cylinder‪
   2. Turbocharger‪	5. Exhaust Brake Air Line‪
   3. Heat Shield‪	6. Exhaust Pipe‪

   Figure 1. Exhaust Brake Assembly Removal, 4-Cylinder Engines

   

   1. Exhaust Brake Valve Housing‪	4. Heat Shield‪
   2. Exhaust Brake Cylinder‪	5. Exhaust Brake Air Line‪
   3. Turbocharger‪	6. Exhaust Pipe‪

   Figure 2. Exhaust Brake Assembly Removal, 6-Cylinder Engines

2. Loosen the clamp securing the exhaust pipe to the exhaust brake valve housing. Slide the exhaust pipe off the housing.

   PERSONAL INJURY ‪
   To avoid injury from the sudden release of a high-pressure hose connection, wear a face shield or goggles.‪

3. Unscrew the exhaust brake compressed-air line fitting from the exhaust brake cylinder and remove the line.
4. Remove four locknuts from the bolts that secure the exhaust brake valve housing to the turbocharger. Remove the housing, leaving the bolts in place. Discard the locknuts.

Section 7.2.2
Exhaust Brake Disassembly, 6-Cylinder Engine

The following commercially available tools are required for this procedure:‪

• Feeler Gauges, 0.3 to 0.5 mm (0.01 to 0.02 in.)
• Depth Slide Gauge, 0 to 200 mm (0 to 7.9 in.)

Disassemble the engine brake as follows:‪

1. With the exhaust brake valve in the open position, loosen the locknut at the base of the ball socket. See Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	9. Adjusting-Lever Bolt‪
   2. Bushing‪	10. Adjusting-Lever Hex nut‪
   3. Shaft‪	11. Locking Element‪
   4. Exhaust Brake Valve‪	12. Ball Socket‪
   5. Valve Mounting Bolt (2 qty.)‪	13. Locknut‪
   6. Bracket‪	14. Exhaust Brake Cylinder‪
   7. Bracket Mounting Bolt (2 qty.)‪	15. Cylinder Mounting Hex nut‪
   8. Adjusting Lever‪	16. Cylinder Mounting Stud‪

   Figure 3. Exhaust Brake Assembly, 6-Cylinder Engine

2. Remove the exhaust brake cylinder from the bracket.
   1. Remove the locking element.
   2. Remove the cylinder mounting hex nut that fastens the exhaust brake cylinder to the cylinder mounting stud.
   3. Remove the ball socket from the adjusting lever.
   4. Remove the cylinder from the bracket.
3. Remove the adjusting lever. See the insert in Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
   1. Turn the adjusting lever to the closed position.
   2. Loosen the hex nut on the adjusting-lever bolt to release the clamping pressure on the exhaust brake shaft.
   3. Slide the adjusting lever off the shaft, taking care not to damage the splines on the shaft.
4. Remove the two bracket mounting bolts that secure the bracket to the exhaust brake valve housing. Remove the bracket from the valve housing.
5. Take the exhaust brake valve out of the valve housing.
   1. Make sure the valve is closed.
   2. Using a socket wrench, remove the two valve mounting bolts that secure the valve to the shaft. See Figure "Exhaust Brake Valve Cross Section, 6-Cylinder Engine" .
      

      1. Exhaust Brake Valve Housing‪	4. Exhaust Brake Valve‪
      2. Shaft‪	5. Valve Mounting Bolts‪
      3. Bushing (2 qty.)‪

      Figure 4. Exhaust Brake Valve Cross Section, 6-Cylinder Engine

   3. Remove the valve through the large end of the valve housing.
6. Using a suitable drift, remove the shaft and the two bushings from the exhaust brake valve housing.

Section 7.2.3
Exhaust Brake Assembly, 6-Cylinder Engine

Assemble the exhaust brake as follows:‪

1. Install the bushing in the bracket side of the exhaust brake valve housing. See Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	9. Adjusting-Lever Bolt‪
   2. Bushing‪	10. Adjusting-Lever Hex nut‪
   3. Shaft‪	11. Locking Element‪
   4. Exhaust Brake Valve‪	12. Ball Socket‪
   5. Valve Mounting Bolt (2 qty.)‪	13. Locknut‪
   6. Bracket‪	14. Exhaust Brake Cylinder‪
   7. Bracket Mounting Bolt (2 qty.)‪	15. Cylinder Mounting Hex nut‪
   8. Adjusting Lever‪	16. Cylinder Mounting Stud‪

   Figure 5. Exhaust Brake Assembly, 6-Cylinder Engine

   1. Using a depth slide gauge, measure 3 mm (0.1 in.) inward on the inner contact surface of the bushing.
   2. Coat the leading (chamfered) edge of the bushing and the measured portion of the inner contact surface with bearing grease.
   3. Using a suitable drift, press in the bushing. Allow the bushing to protrude slightly outside the valve housing.
2. Insert the shaft into the valve housing and bushing.
3. Install the second bushing in the opposite side of the valve housing.
   1. Using a depth slide gauge, measure 3 mm (0.1 in.) inward on the inner contact surface of the bushing.
   2. Coat the leading edge of the bushing and the measured portion of the inner contact surface with bearing grease.
   3. Using a suitable drift, press in the bushing. Allow the bushing to protrude slightly outside the valve housing
4. Install the valve on the shaft.
   1. Place the valve inside the valve housing.
   2. Rotate the shaft until the bolt holes are parallel with the direction of the exhaust flow.
   3. Apply anti-seize compound to the threads of the two valve mounting bolts.
   4. Place the valve against the shaft in the closed position (resting against the valve stop). Align the bolt holes in the valve and shaft.
   5. Install the two valve mounting bolts through the valve and into the shaft from the direction shown in Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
   6. Using a socket wrench, tighten the bolts 23 N·m (17 lb·ft).
5. Check the axial play of the shaft. See Figure "Exhaust Brake Valve Cross Section, 6-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	4. Exhaust Brake Valve‪
   2. Shaft‪	5. Valve Mounting Bolts‪
   3. Bushing (2 qty.)‪

   Figure 6. Exhaust Brake Valve Cross Section, 6-Cylinder Engine

   1. Center the shaft in the valve housing
   2. Using a suitable drift, drive the bushings in evenly on both sides until the axial play is correct.
   3. Using a feeler gauge, check that the axial play of the shaft between the bushings is 0.3 to 0.5 mm (0.01 to 0.02 in.). Make sure the projection of the bushings inside the valve housing is the same on both sides.
6. Using a feeler gauge, check the outside edge (perimeter) of the closed valve to make sure it does not touch the housing at any point.
7. Install the bracket on the exhaust brake valve housing with the two bracket mounting bolts. Tighten the bolts 23 N·m (17 lb·ft).
8. Install the adjusting lever. See the inset box in See Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
   1. Rotate the valve to the fully open position in the valve housing.
   2. Fit the adjusting lever on the splines of the shaft so the adjusting-lever stop rests against the bottom lip of the bracket.
9. Check the valve setting by rotating it to the closed position. The adjusting-lever stop must be approximately 1 mm (0.04 in.) below the lip of the bracket, not touching the bracket.
10. Install the exhaust brake cylinder on the bracket.
    1. Install the cylinder and a new cylinder mounting hex nut on the mounting stud but do not tighten. See Figure "Exhaust Brake Assembly, 6-Cylinder Engine" .
    2. With the valve open, turn the ball socket clockwise until the exhaust brake cylinder is preloaded at 1.0 to 2.0 mm (0.04 to 0.08 in.). Tighten the locknut against the ball socket.
    3. Install the locking element.
    4. Tighten the cylinder mounting hex nut onto the mounting stud until firm.
11. Install the exhaust brake assembly. Refer to "7.2.6 Exhaust Brake Assembly Installation" .

Section 7.2.4
Exhaust Brake Disassembly, 4-Cylinder Engine

The following commercially available tools are required for this procedure:‪

• Feeler Gauges, 0.3 to 0.5 mm (0.01 to 0.02 in.)
• Depth Slide Gauge, 0 to 200 mm (0 to 7.9 in.)

Disassemble the exhaust brake as follows:‪

1. With the exhaust brake valve in the open position, loosen the locknut at the base of the ball socket. See Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	10. Adjusting-Lever Hex nut‪
   2. Bushing‪	11. Locking Element‪
   3. Shaft‪	12. Ball Socket‪
   4. Exhaust Brake Valve‪	13. Locknut‪
   5. Valve Mounting Bolt (2 qty.)‪	14. Exhaust Brake Cylinder‪
   6. Bracket‪	15. Cylinder Mounting Hex nut‪
   7. Bracket Mounting Bolt (2 qty.)‪	16. Washer‪
   8. Adjusting Lever‪	17. Bracket Pin‪
   9. Adjusting-Lever Bolt‪

   Figure 7. Exhaust Brake Assembly, 4-Cylinder Engine

2. Remove the exhaust brake cylinder from the bracket. See Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   1. Remove the locking element.
   2. Remove the hex nut that fastens the exhaust brake cylinder to the bracket pin.
   3. Remove the ball socket from the adjusting lever.
   4. Remove the cylinder from the bracket.
3. Remove the adjusting lever. See the insert in Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   1. Turn the adjusting lever to the closed position.
   2. Loosen the hex nut on the adjusting-lever bolt to release the clamping pressure on the exhaust brake shaft.
   3. Slide the adjusting lever off the shaft, taking care not to damage the splines on the shaft.
4. Remove the two bracket mounting bolts that secure the bracket to the exhaust brake valve housing. Remove the bracket from the valve housing.
5. Remove the exhaust brake valve.
   1. Make sure the valve is closed.
   2. Using a socket wrench, remove the two valve mounting bolts that secure the valve to the shaft. See Figure "Exhaust Brake Valve Cross Section, 4-Cylinder Engine" .
      

      1. Exhaust Brake Valve Housing‪	4. Exhaust Brake Valve‪
      2. Shaft‪	5. Valve Mounting Bolts‪
      3. Bushing (2 qty.)‪

      Figure 8. Exhaust Brake Valve Cross Section, 4-Cylinder Engine

   3. Remove the valve through the large end of the valve housing.
6. Using a suitable drift, remove the shaft and the two bushings from the exhaust brake valve housing.

Section 7.2.5
Exhaust Brake Assembly, 4-Cylinder Engine

‪

1. Install the bushing in the bracket side of the exhaust brake valve housing. See Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	10. Adjusting-Lever Hex nut‪
   2. Bushing‪	11. Locking Element‪
   3. Shaft‪	12. Ball Socket‪
   4. Exhaust Brake Valve‪	13. Locknut‪
   5. Valve Mounting Bolt (2 qty.)‪	14. Exhaust Brake Cylinder‪
   6. Bracket‪	15. Cylinder Mounting Hex nut‪
   7. Bracket Mounting Bolt (2 qty.)‪	16. Washer‪
   8. Adjusting Lever‪	17. Bracket Pin‪
   9. Adjusting-Lever Bolt‪

   Figure 9. Exhaust Brake Assembly, 4-Cylinder Engine

   1. Using a depth slide gauge, measure 3 mm (0.1 in.) inward on the inner contact surface of the bushing.
   2. Coat the leading (chamfered) edge of the bushing and the measured portion of the inner contact surface with bearing grease.
   3. Using a suitable drift, press in the bushing. Allow the bushing to protrude slightly outside the valve housing.
2. Insert the shaft into the valve housing and bushing.
3. Install the second bushing in the other side of the valve housing.
   1. Using a depth slide gauge, measure 3 mm (0.1 in.) inward on the inner contact surface of the bushing.
   2. Coat the leading edge of the bushing and the measured portion of the inner contact surface with bearing grease.
   3. Using a suitable drift, press in the bushing. Allow the bushing to protrude slightly outside the valve housing.
4. Install the valve on the shaft.
   1. Place the valve inside the valve housing.
   2. Rotate the shaft until the bolt holes are parallel with the direction of the exhaust flow.
   3. Apply anti-seize compound to the threads of the two valve mounting bolts.
   4. Place the valve against the shaft in the closed position (resting against the valve stop). Align the bolt holes in the valve and shaft.
   5. Install the two valve mounting bolts through the valve and into the shaft from the direction shown in Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   6. Using a socket wrench, tighten the bolts 23 N·m (17 lb·ft).
5. Check the axial play of the shaft. See Figure "Exhaust Brake Valve Cross Section, 4-Cylinder Engine" .
   

   1. Exhaust Brake Valve Housing‪	4. Exhaust Brake Valve‪
   2. Shaft‪	5. Valve Mounting Bolts‪
   3. Bushing (2 qty.)‪

   Figure 10. Exhaust Brake Valve Cross Section, 4-Cylinder Engine

   1. Center the shaft in the valve housing.
   2. Using a suitable drift, drive the bushings in evenly on both sides until the axial play is correct.
   3. Using a feeler gauge, check that the axial play of the shaft between the bushings is 0.3 to 0.5 mm (0.01 to 0.02 in.). Make sure the projection of the bushings inside the valve housing is the same on both sides.
6. Using a feeler gauge, check the outside edge (perimeter) of the closed valve to make sure it does not touch the housing at any point.
7. Install the bracket on the exhaust brake valve housing with the two bracket mounting bolts. Tighten the bolts 23 N·m (17 lb·ft).
8. Install the adjusting lever. See in insert in See Figure "Exhaust Brake Assembly, 4-Cylinder Engine" .
   1. Rotate the valve to the fully open position in the valve housing.
   2. Fit the adjusting lever on the splines of the shaft so the adjusting-lever stop rests against the bottom lip of the bracket.
9. Check the valve setting by rotating it to the closed position. The adjusting-lever stop must be about 1 mm (0.04 in.) below the lip of the bracket, not touching the bracket.
10. Install the exhaust brake cylinder on the bracket.
    1. Place a washer and the cylinder on the bracket pin. See Figure "Exhaust Brake Assembly, 4-Cylinder Engine" . Install a washer and hex nut on the end of the bracket pin but do not tighten.
    2. With the valve open, turn the ball socket clockwise until the exhaust brake cylinder is preloaded at 1.0 to 2.0 mm (0.04 to 0.08 in.). Tighten the locknut against the ball socket.
    3. Install the locking element.
    4. Tighten the hex nut on the bracket pin.
11. Install the exhaust brake assembly on the engine. Refer to "7.2.6 Exhaust Brake Assembly Installation" .

Section 7.2.6
Exhaust Brake Assembly Installation

Install the exhaust brake assembly as follows:‪

Note: Four new prevailing torque locknuts (P/N: A 000 990 31 50) are required for the installation of the exhaust brake assembly.

1. Clean the mating surfaces on the exhaust brake valve housing and the turbocharger.
2. Install the exhaust brake valve housing on the turbocharger by slipping the housing over the four turbocharger bolts. Install four new prevailing torque locknuts (P/N: A 000 990 31 50) on the turbocharger bolts. Tighten the locknuts 50 N·m (37 lb·ft).
3. Install the compressed-air line on the exhaust brake cylinder.
4. Clean the sealing surfaces on the exhaust pipe and exhaust brake valve housing.
5. Slide the exhaust pipe and clamp over the end of the housing to the stop. Tighten the clamp.
6. Install the heat shield on the exhaust brake valve housing and the turbocharger, using four hex head bolts.