Belt Tensioner not operating properly on my 86 Mercedes 300E

I suggest buying the CD with instructions and diagrams. it is not impossible but important to do it right and correct torqing of bolts is critical.

Also, Imperative that you replace the belt tensioner and the small shock attached to it. These usually fail shortly after the original water pump. replacing it now is easy replacing it later is very painful.

This label shows the accessory belt routing on a Lumina with a 3.1L engine

1. Disconnect the negative battery cable.
   
2. Remove the drive belt shield.
   
3. Fit a 3/8 inch breaker bar or ratchet to the square hole in the tensioner. Lift, or rotate the tensioner off of the drive belt. When the tension on the belt is removed, slide the drive belt from the pulleys.
   

To install:

1. Taking care to follow the proper routing of the belt, slip the belt onto the pulleys. As a help, note that the water pump pulley is usually driven from the back (smooth side) of the belt.
   
2. Fit a 3/8 -inch breaker bar or ratchet to the square hole in the tensioner. Lift, or rotate the tensioner and, with the belt in place, gently release the tensioner.
   
3. Verify that the belt is correctly routed and aligned in the proper grooves of the accessory drive belt pulleys. Inspect the drive belt length scale on the drive belt tensioner for the proper indicated length. If the drive belt length scale does not indicate the proper installed length, the belt may be incorrect, incorrectly installed, worn out or the tensioner may be defective.
   
4. Connect the negative battery cable. Start the vehicle and verify correct operation.
   

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1. Remove or disconnect the following:
   
   
2. Negative battery cable Accessory drive belt and tensioner Timing belt cover Right front wheel Right inner splash shield Crankshaft pulley
   
3. Align the timing marks.

1. Removing Timing Belt

1. Loosen the timing belt tensioner bolt (1).
2. Use an 8mm Allen wrench, and turn the tensioner (2) counterclockwise 1 / 4 turn.
3. Insert a 1 / 8 inch drill bit in the hole (3) to lock the belt tensioner in place.
4. Remove the timing belt (4).
   
   To Install :
   
   
5. Install the timing belt in a counterclockwise direction starting at the crankshaft.
   
6. Remove the drill bit to unlock the timing belt tensioner.
   
7. Rotate the crankshaft two complete turns and check that the timing marks align.
   
8. Tighten the tensioner bolt to 15-22 ft. lbs. (20-30 Nm).
   
9. Reinstall or connect the following:
   
   Crankshaft pulley. Tighten the bolt to 81-96 ft. lbs. (110-130 Nm). Right inner splash shield Right front wheel Timing belt cover Accessory drive belt and tensioner Negative battery cable
10. Start the engine and check for proper operation
    

Head to benzworld.org for help.

need to find the belt tensioner and spring it forward then pull belt off make sure you remember the sequence the belt goes

SOUNDS LIKE IT COULD BE YOUR FULE PUMP.

probly need to have steering pump inspected -the library has many books in section 629 for more opinions

You can do it all at once.

This may be of some help.

You may remove alternator pulley and replace with belt over it.