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MBE 4000 EXHAUST BRAKE ASSEMBLY

Engine braking is controlled by a pneumatically-operated exhaust brake on the turbocharger and by a constant-throttle system. For greater braking power, an optional turbo brake is available. ‪

Exhaust Brake Assembly Removal

Remove the exhaust brake assembly as follows: ‪

  1. Disconnect the batteries.

    PERSONAL INJURY

    To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.

  2. Chock the rear tires and tilt the hood.
  3. To gain access to the exhaust brake, remove the air cleaner.

    PERSONAL INJURY

    To avoid injury, never remove any engine component while the engine is running.

    PERSONAL INJURY

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

  4. Remove the exhaust brake compressed-air line from the exhaust brake cylinder.
  5. Remove the clamp that fastens the exhaust pipe to the brake valve housing. See Figure 42129 .

    1. Exhaust Pipe ‪

    5. Mounting Stud ‪

    2. Constant-Torque Clamp ‪

    6. Turbocharger ‪

    3. Bracket ‪

    7. Brake Valve Housing ‪

    4. Exhaust Brake Cylinder ‪

    Exhaust Brake Assembly Removal

  6. Remove the locknuts that attach the brake valve housing to the studs on the turbocharger. Remove the housing from the engine.

Exhaust Brake Disassembly

Disassemble the exhaust brake unit as follows: ‪

  1. Remove the exhaust brake assembly from the engine. See Figure 42130 .

    1. Mounting Bolt ‪

    11. Bracket Mounting Bolt (2 qty.) ‪

    2. Washer ‪

    12. Bracket ‪

    3. Exhaust Brake Cylinder ‪

    13. Locknut ‪

    4. Locking Element ‪

    14. Rear Bushing ‪

    5. Jam Nut ‪

    15. Valve Mounting Bolt (2 qty.) ‪

    6. Ball Socket ‪

    16. Exhaust Brake Valve ‪

    7. Spacer ‪

    17. Brake Valve Housing ‪

    8. Adjusting-Lever Hexnut ‪

    18. Shaft ‪

    9. Adjusting Lever ‪

    19. Front Bushing (integral to shaft) ‪

    10. Adjusting Lever Bolt ‪

    Exhaust Brake Assembly

  2. Remove the exhaust brake cylinder from the bracket.
    1. Remove the mounting bolt, locknut, spacer, and washers from the exhaust brake cylinder. Discard the locknut.
    2. Remove the locking element from the ball socket.
    3. Separate the ball socket from the adjusting lever.
    4. Remove the cylinder from the bracket.
  3. Check the end play (movement back and forth) and radial play (movement up and down) of the exhaust brake shaft. If there is too much play in either direction, the shaft is worn and must be replaced. Listed in Table are the acceptable ranges.

    Description ‪

    mm (inch) ‪

    End Play (axial play) ‪

    0.4 - 0.7 mm (0.016 - 0.028 in.) ‪

    Radial Play ‪

    0.200 - 0.263 mm (0.00787 - 0.01035 in.) ‪

    Exhaust Brake Shaft Specifications
  4. Remove the adjusting lever.
    1. Remove the hexnut and bolt on the adjusting lever to release the clamping pressure on the exhaust brake shaft.
    2. Lift the adjusting lever off the shaft, taking care not to damage the splines of the shaft.
  5. Remove the two bracket mounting bolts that secure the bracket to the exhaust brake valve housing. Remove the bracket from the valve housing.
  6. Remove the bolts that fasten the exhaust brake valve (butterfly valve) to the shaft. Remove the exhaust brake valve from the brake valve housing.
  7. Using a suitable drift, press the shaft, and its integral front bushing, out of the brake valve housing.
  8. Using a suitable drift, press the rear bushing out of the brake valve housing.

Exhaust Brake Assembly

Assemble the exhaust brake unit as follows: ‪

  1. Install the rear bushing in the bracket side of the exhaust brake valve housing. See Figure 42131 .

    1. Front Bushing (on shaft) ‪

    4. Exhaust Brake Valve ‪

    2. Brake Valve Housing ‪

    5. Shaft ‪

    3. Valve Mounting Bolt (2 qty.) ‪

    6. Rear Bushing ‪

    Bushing Alignment

    1. Lubricate the rear bushing with a light coating of bearing grease.
    2. Using a suitable drift, press in the bushing. Allow the bushing to project slightly into the valve housing bore.
  2. Measure bushing projection (dimension B, listed in Table .)

    Description ‪

    mm (inch) ‪

    Distance Between the Two Projecting Bushings (Ref. A) ‪

    84.2 (3.31) ‪

    Projection of the Rear Bushing into the Brake Valve Housing (Ref. B) ‪

    2.6 (0.10) ‪

    Bushing Alignment Specifications
    1. Choose a feeler gauge equal to dimension B, 2.6 mm (0.10 inch).
    2. Insert the feeler gauge into the bore in the brake valve housing until it is touching the rear bushing.
    3. Adjust the projection inward or outward until the face of the bushing is flush with the feeler gauge.
  3. Install the shaft, with its integral front bushing, into the brake valve housing (with the rear bushing installed).
    1. Lubricate the front bushing with a light coating of bearing grease.
    2. Using a suitable drift, press in the shaft until the front bushing projects slightly into the other side of the brake valve housing bore.
  4. Measure the distance between the bushing faces inside the brake valve housing (dimension A, see Figure 42131 .)
    1. Using calipers or another suitable measuring device, measure the distance between the face of the front bushing and the face of the rear bushing.
    2. Adjust the distance until it is equal to 84.2 mm (3.31 inches).
  5. Install the exhaust brake valve on the shaft.
    1. Position the valve correctly on the shaft. The valve should be centered inside the valve housing, and equidistant between the two bushings.
    2. Apply anti-seize compound to the threads of the two valve mounting bolts.
    3. Install and tighten the two valve mounting bolts 30 Nm (22 lbft).
    4. With the bolts tightened, move the valve to and fro a few times to make sure it does not interfere with the brake valve housing at any point.
  6. Install the bracket on the brake valve housing. Tighten the bracket mounting bolts 35 Nm (25 lbft).
  7. Install the adjusting lever on the shaft.
    1. Rotate the valve until it is fully open.
    2. Install the adjusting lever so that the lever stop rests against the bracket with the valve still fully open.
    3. Install the adjusting-lever bolt and nut. Tighten the nut 15 Nm (11 lbft).
  8. Install the exhaust brake cylinder on the bracket.
    1. Install the bolt, washers, spacer, and a new locknut on the cylinder and bracket, as removed.
    2. Measure the length, listed in Table , of the uninstalled pneumatic cylinder, for specified preload after installation. See Figure 42262 , measurement B.

      1. Pneumatic Cylinder ‪

      2. Ball Joint ‪

      Exhaust Brake Assembly

    3. Designation ‪

      Measurement, mm (inch) ‪

      Length of installed pneumatic cylinder ‪

      187.0 mm (7.36 in.) ‪

      Length of uninstalled pneumatic cylinder, for specified preload after installation ‪

      183.50 - 184.50 mm (7.22 - 7. 26 in.) ‪

      Length of Installed and Uninstalled Exhaust Brake Assembly
    4. With the valve open, turn the ball socket (on the cylinder) until it sits right on top of the ball stud (on the adjusting lever).
    5. Measure the length of the installed pneumatic cylinder. See Figure 42262 , measurement A.
    6. With the valve still open, turn the ball socket over two full turns.
    7. Using high temperature resisting grease, fit the ball socket onto the ball stud, and install the locking element.
    8. Tighten the locknut 25 Nm (18 lbft).
  9. Install the exhaust brake assembly on the engine.

Exhaust Brake Assembly Installation

Install the exhaust brake assembly as follows: ‪

  1. Clean the mating surfaces on the brake valve housing and the turbocharger.
  2. Install the brake valve housing on the turbocharger by slipping the housing over the turbocharger studs. Tighten the locknuts 50 Nm (37 lbft).

    PERSONAL INJURY

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

  3. Install the compressed-air line on the exhaust brake cylinder.
  4. Clean the sealing surfaces on the exhaust pipe and brake valve housing.
  5. Slide the exhaust pipe and clamp over the end of the housing. Tighten the clamp.
  6. Install the air cleaner.
  7. Connect the batteries, lower the hood, and remove the chocks from the rear tires.