MBE 900

Section 1.10 Flywheel

Section 1.10

The flywheel must be removed for service operations such as replacing the crankshaft radial oil seal, the crankshaft, or the flywheel housing.‪

Section 1.10.1
Flywheel Removal

Remove the flywheel as follows:‪

  1. Remove the transmission.
  2. Remove the clutch from the flywheel.
  3. Pull the crank angle position sensor out of the flywheel housing about 8 mm (5/16 in.). See Figure "Flywheel, Exploded View" .
    Click to see this graphic in a separate window

     1. Crank Angle Position Sensor‪

     3. Bolt, M14 x 1.5 (8 qty.)‪

     2. Flywheel‪

     4. Flywheel Housing, End Cover Location‪

    Figure 1. Flywheel, Exploded View

  4. Remove the end cover from the flywheel housing and install the engine barring tool J-46392 . Tighten the bolts on the barring device 25 N·m (18 lb·ft). Refer to "1.13.1 Engine Barring Tool Installation" . Insert the locking pin to block the device from rotating.
  5. Using the 16-mm flywheel and main pulley socket tool J-46385 , remove two flywheel socket-head bolts from the flywheel, one from each side of the bolt circle.
  6. Install the two flywheel guide studs J-46389 into the empty bolt holes in the center of the flywheel. See Figure "Flywheel, Exploded View" .


    To avoid injury from a falling flywheel when removing the last bolt, hold the flywheel against the crankshaft by hand to prevent it from slipping off the crankshaft. The flywheel is not doweled to the crankshaft.‪

  7. Remove the remaining six flywheel bolts.
  8. Remove the engine barring tool J-46392 . Refer to "1.13.2 Engine Barring Tool Removal" .
  9. Remove the flywheel, leaving the guide studs in place. See Figure "Flywheel Removal" .
    Click to see this graphic in a separate window

     1. Flywheel Guide Stud‪

     3. Flywheel Mounting Bolt‪

     2. Bolt Used as Handle‪

    Figure 2. Flywheel Removal

    1. On opposite sides of the bolt circle, insert a clutch bolt into each of two threaded clutch bolt holes.
    2. Using the two bolts as handles, dislodge the flywheel from the crankshaft flange and remove it from the flywheel housing.
    3. After removing the flywheel, remove the bolts from the clutch bolt holes.
  10. Inspect the flywheel bolts. Replace the bolts if any of the shanks are stretched beyond the maximum length of 61.0 mm (2.40 in.).
Flywheel Inspection and Machining

Inspect the flywheel as follows:‪

  1. Thoroughly clean the flywheel and check the clutch surface for cracks, burned spots, or scoring.
  2. Using an accurate straightedge and a feeler gauge, check the friction (clutch) surface for evenness. See Figure "Checking the Friction Surface for Evenness" . If the surface has areas that are too high or too low as Listed in Table "Flywheel Specifications" , machine the surface or replace the flywheel.
    Click to see this graphic in a separate window

    Figure 3. Checking the Friction Surface for Evenness

  3. Check the bearing surface and the threaded holes for wear and damage.

    Note: Before beginning any machining work on the flywheel, check it to see if machining is possible. If the scores or cracks are deeper than 1 mm (0.04 in.), replace the flywheel. The after-machining specifications are listed in Table "Flywheel Specifications" , Ref E.

  4. Machine the flywheel friction surface, if required, to the specifications listed in Table "Flywheel Specifications" . See Figure "Machining the Flywheel Friction Surface" and see Figure "Flywheel Cross Section" . The surface finish (peak-to-valley height) after machining should be 16 µm (630 µin). A rougher surface finish will cause rapid clutch lining wear, while a smoother finish could cause difficulties in clutch disengagement.
    Click to see this graphic in a separate window

    Figure 4. Machining the Flywheel Friction Surface

    Note: After machining, the friction surface must not have any cavities or chatter marks.


    Specification mm (in.)‪

    Flywheel Outer Diameter (see Figure , Ref. A)‪

    443 (17.4)‪

    Flywheel Shoulder Diameter‪

    (for ring gear mounting - see Figure , Ref. B)‪

    392.435–392.575 (15.4502–15.4557 )‪

    Flywheel Diameter at Crankshaft Flange‪

    (see Figure , Ref. C)‪

    114.960–115.020 (4.5260–4.5283 )‪

    Flywheel Diameter for Mounting Clutch‪

    (see Figure , Ref. D)‪

    435.000–435.063 (17.1260–17.1285 )‪

    Flywheel Minimum Width Between Friction Surface and Mounting Flange After Repairs (see Figure , Ref. E)‪

    55 (2.17)‪

    Flywheel Maximum Overall Width‪

    (see Figure , Ref. F)‪

    56 (2.20)‪

    Pitch Circle Diameter for Clutch‪

    373.7 (14.71)‪

    Peak-to-Valley Height (Rz ) of Clutch Friction Surface‪

    16 µm (630 µin)‪

    Flywheel Permissible Deviation From True (radial and lateral)‪

    0.05 (0.002)‪

    Table 4. Flywheel Specifications
    Click to see this graphic in a separate window

     1. Flywheel‪

     2. Ring Gear‪

    Figure 5. Flywheel Cross Section

  5. Check the radial and lateral deviation from true of the flywheel. The deviation from true must not exceed 0.05 mm (0.002 inch).

Section 1.10.2
Flywheel Installation

Install the flywheel as follows:‪

  1. Grease the ring gear with a suitable heavy-duty grease.


    To avoid injury from a falling component, ensure a proper lifting device is used. Never stand beneath a suspended load.‪

  2. Align the flywheel with the location dowel on the crankshaft flange. Install the flywheel over the guide studs.
  3. Install the engine barring tool J-46392 in the flywheel housing and secure with two bolts. Insert the locating pin and make sure the tool gears do not rotate. Refer to "1.13.1 Engine Barring Tool Installation" .
  4. Lightly oil the threads on eight M14 x 1.5 multipoint socket-head bolts.
  5. Tighten the eight bolts in three stages as listed in Table "Tightening Stages, Flywheel Mounting Bolts" . In each stage, use the torquing sequence in the next illustration (see Figure "Torquing Sequence, Flywheel" ).


    Max. Shaft Length‪

    Tightening Stage‪

    Torque Value N·m (lb·ft)‪

    M14 x 1.5‪

    61.0 mm (2.40 in.)‪

    Stage 1‪

    50 (37)‪

    Stage 2‪

    125 (92)‪

    Stage 3‪

    additional 90 degrees‪

    Table 7. Tightening Stages, Flywheel Mounting Bolts
    Click to see this graphic in a separate window

    Figure 6. Torquing Sequence, Flywheel

    1. Install six bolts to hold the flywheel in position.
    2. Remove the two guide studs and install the two remaining bolts in their place.
    3. Tighten the bolts, in the correct torquing sequence, 50 N·m (37 lb·ft ).
    4. Repeat the torquing sequence to tighten the bolts 125 N·m ( 92 lb·ft).
    5. Using the same torquing sequence, turn the flywheel bolts an additional 90 degrees.
  6. Remove the engine barring tool. Install the end cover on the flywheel housing with two bolts. Tighten the bolts 25 N·m (18 lb·ft).
  7. Press the crank angle position sensor into the flywheel housing as far as the stop. Check the crank angle position sensor for proper installation.
  8. Install the clutch on the flywheel, then install the transmission.

MBE 900 Service Manual - 6SE414
Generated on 10-13-2008

Leave a Reply

Your email address will not be published. Required fields are marked *