Mercedes-Benz Cars 2000-05

Rocker Arms & Shafts

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Removal & Installation



All engines except the 112 and 113 are not equipped with rocker arms/shafts. The camshaft(s) act directly on valve tappets. On the 112 and 113 engines, the rocker arm/shaft is part of the camshaft bearing cap assembly and is called the camshaft bearing bridge. This procedure is for removing and installing the camshaft bearing bridge.

The Diesel engine does not use rocker arms. The camshafts act directly on the hydraulic valve tappets.

The rocker arm/shaft is part of the camshaft bearing cap assembly and is called the camshaft bearing bridge. This procedure is for removing and installing the camshaft bearing bridge.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Cylinder head cover
     

  4.  
  5. Rotate the engine clockwise to position the crankshaft 40 degrees After Top Dead Center (ATDC).
  6.  


WARNING
The engine must not be rotated backward.



Generator
 
Timing chain tensioner
 

  1. Cable tie the timing chain to the camshaft sprocket.

    Camshaft bearing bridge bolts in the reverse order of installation, starting at 16 for the 3.2L engine, and 20 for the 4.3L engine
     

  2.  


NOTE
The camshaft bearing bridge must not be disassembled. If damage exists at the valve gear or at the top half of the camshaft bearing journal, the complete cylinder head should be replaced.



Click image to see an enlarged view

Fig. Camshaft bearing bridge bolt removal sequence-3.2L and 3.7L engines



Click image to see an enlarged view

Fig. Camshaft bearing bridge bolt removal sequence -4.3L and 5.0L engine

To install:

  1. Lubricate the camshaft bearing journals.
  2.  
  3. Install or connect the following:

    Camshaft bearing bridge and tighten the bolts to 88 inch lbs. (10 Nm) plus 90° in the reverse of the removal sequence.
     

  4.  
  5. Remove the cable ties from the camshaft sprockets.

    Timing chain tensioner with a new gasket and tighten to 59 ft. lbs. (80 Nm)
     
    Cylinder head covers and tighten the bolts to 88 inch lbs. (10 Nm)
     
    Negative battery cable
     

  6.  
  7. Read fault memory, encode the radio and normalize the power windows.
  8.  
  9. Start the vehicle and check for leaks.
  10.  

All engines except the 112 and 113 are not equipped with rocker arms/shafts. The camshaft(s) act directly on valve tappets. On the 112 and 113 engines, the rocker arm/shaft is part of the camshaft bearing cap assembly and is called the camshaft bearing bridge. This procedure is for removing and installing the camshaft bearing bridge.

The Diesel engine does not use rocker arms. The camshafts act directly on the hydraulic valve tappets.

All engines except the 112 and 113 are not equipped with rocker arms/shafts. The camshaft(s) act directly on valve tappets. On the 112 and 113 engines, the rocker arm/shaft is part of the camshaft bearing cap assembly and is called the camshaft bearing bridge. This procedure is for removing and installing the camshaft bearing bridge.

All engines except the M112 and M113 series are not equipped with rocker arms/shafts. The camshaft(s) act directly on valve tappets. On the M112 and M113 engines, the rocker arm/shaft is part of the camshaft bearing cap assembly and is called the camshaft bearing bridge. This procedure is for removing and installing the camshaft bearing bridge.

2.6L, 2.8L And 3.2L (112) And 4.3L, 5.0L And 5.5L (113) Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Cylinder head cover
     

  4.  
  5. Rotate the engine clockwise to position the crankshaft 40 degrees After Top Dead Center (ATDC).
  6.  


WARNING
The engine must not be rotated backward.



Generator
 
Timing chain tensioner
 

  1. Cable tie the timing chain to the camshaft sprockets and remove the sprockets.
  2.  
  3. Loosen the camshaft bearing bridge bolts in reverse of the tightening sequence.
  4.  


NOTE
The camshaft bearing bridge must not be disassembled. If damage exists at the valve gear or at the top half of the camshaft bearing journal, the complete cylinder head should be replaced.

To install:



Click image to see an enlarged view

Fig. Camshaft bearing bridge tightening sequence-2.6L, 2.8L and 3.2L (112) engines



Click image to see an enlarged view

Fig. Camshaft bearing bridge tightening sequence-4.3L, 5.0L and 5.5L (113) engines

  1. Lubricate the camshaft bearing journals.
  2.  
  3. Install or connect the following:

    Camshaft bearing bridge. Torque the bolts to 11 ft. lbs. (15 Nm) in sequence as illustrated.
     
    Camshaft sprockets
     
    Timing chain tensioner with new gasket. Torque to 59 ft. lbs. (80 Nm).
     
    Cylinder head covers. Torque to 88 inch lbs. (10 Nm).
     

  4.  
  5. Connect the negative battery cable, start the vehicle and check operation.
  6.  

3.2L (112) And 4.3L (113) Engines
  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Cylinder head cover
     

  4.  
  5. Rotate the engine clockwise to position the crankshaft 40 degrees after top dead center.
    WARNING
    The engine must not be rotated backwards.

  6.  
  7. Remove or disconnect the following:

    Generator
     
    Timing chain tensioner
     

  8.  
  9. Cable tie the timing chain to the camshaft sprockets and remove the sprockets.
  10.  
  11. Loosen the camshaft bearing bridge bolts in reverse of the illustrated sequence.
    NOTE
    The camshaft bearing bridge must not be disassembled. If damage exists at the valve gear or at the top half of the camshaft bearing journal, the complete cylinder head should be replaced.

  12.  

To install:

  1. Lubricate the camshaft bearing journals.
  2.  
  3. Install or connect the following:

    Camshaft bearing bridge. Torque the bolts to 11 ft. lbs. (15 Nm) in sequence as illustrated
     
    Camshaft sprockets
     
    Timing chain tensioner with new gasket. Torque to 59 ft. lbs. (80 Nm)
     
    Cylinder head covers. Torque to 88 inch lbs. (10 Nm)
     

  4.  
  5. Connect the negative battery cable, start the vehicle and check operation.
  6.  

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Cylinder head cover
     

  4.  
  5. Rotate the engine clockwise to position the crankshaft 40 degrees after top dead center.
    WARNING
    The engine must not be rotated backwards.

  6.  
  7. Remove or disconnect the following:

    Generator
     
    Timing chain tensioner
     

  8.  
  9. Cable tie the timing chain to the camshaft sprockets and remove the sprockets.
  10.  
  11. Loosen the camshaft bearing bridge bolts in reverse of the illustrated sequence.
    NOTE
    The camshaft bearing bridge must not be disassembled. If damage exists at the valve gear or at the top half of the camshaft bearing journal, the complete cylinder head should be replaced.

  12.  

To install:

  1. Lubricate the camshaft bearing journals.
  2.  
  3. Install or connect the following:

    Camshaft bearing bridge. Torque the bolts to 11 ft. lbs. (15 Nm) in sequence as illustrated
     
    Camshaft sprockets
     
    Timing chain tensioner with new gasket. Torque to 59 ft. lbs. (80 Nm)
     
    Cylinder head covers. Torque to 88 inch lbs. (10 Nm)
     

  4.  
  5. Connect the negative battery cable, start the vehicle and check operation.
  6.  

M112 And M113 Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Cylinder head cover
     

  4.  
  5. Rotate the engine clockwise to position the crankshaft 40 degrees After Top Dead Center (ATDC).
    WARNING
    The engine must not be rotated backward.



    Generator
     
    Timing chain tensioner
     

  6.  
  7. Cable tie the timing chain to the camshaft sprockets and remove the sprockets.
  8.  
  9. Loosen the camshaft bearing bridge bolts in reverse of the tightening sequence.
    NOTE
    The camshaft bearing bridge must not be disassembled. If damage exists at the valve gear or at the top half of the camshaft bearing journal, the complete cylinder head should be replaced.

  10.  

To install:

Click image to see an enlarged view

Fig. Camshaft bearing bridge tightening sequence-M112 engines



Click image to see an enlarged view

Fig. Camshaft bearing bridge tightening sequence-M113 engines

  1. Lubricate the camshaft bearing journals.
  2.  
  3. Install or connect the following:

    Camshaft bearing bridge. Torque the bolts to 88 inch lbs. (10 Nm) plus 90 degrees in the reverse of the removal sequence.
     
    Camshaft sprockets
     
    Timing chain tensioner with new gasket. Torque to 59 ft. lbs. (80 Nm).
     
    Cylinder head covers.
     

  4.  
  5. Connect the negative battery cable, start the vehicle and check operation.
  6.  

 
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