BMW Coupes and Sedans 1970-1988 Repair Guide

Starter

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See Figure 1



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Fig. Fig. 1: Exploded view of a starter assembly

REMOVAL & INSTALLATION



1970-82 Models
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the starter power cable at the solenoid by removing the nut and washer, and pulling the connection off the terminal.
  4.  
  5. On fuel injected 4-cylinder models, remove the intake cowl from the mixture control unit. On 6-cylinder fuel injected models, remove No. 6 intake tube.
  6.  
  7. Pull off the 2 solenoid connectors, tagging each as it is being removed.
  8.  
  9. On 4-cylinder models, disconnect the mounting bracket at the engine block by removing the 2 bolts.
  10.  
  11. On 528e models, remove the front Allen screw from the rear of the starter.
  12.  
  13. Remove the starter mounting bolts from the transmission and remove the unit.
  14.  

To install:
  1. Position the starter into place and secure with the mounting bolts.
  2.  
  3. Install the terminal wires and main power cable and tighten. Before completing the procedure, check and make sure none of the wires are rubbing on any part of the engine or starter. This could cause the wire insulation to rub off and cause a short circuit.
  4.  
  5. Connect the negative battery cable.
  6.  

1983-88 Models

See Figure 2

  1. Disconnect the negative battery cable.
  2.  
  3. On 6-cylinder models with 6 identical intake tubes, it may be necessary to remove the No. 6 intake tube for clearance. On 4-cylinder models, remove the intake cowl from the mixture control unit.
  4.  
  5. On 318i models, remove the wire holding bracket.
  6.  



Click image to see an enlarged view

Fig. Fig. 2: On 318i models, remove the nut and bracket from the starter

  1. On 1983-87 325 models;
    1. Remove the air cleaner with the airflow sensor.
    2.  
    3. Make sure the engine is cool and then drain the coolant into a clean container. Disconnect the heater hose that runs near the starter. Remove the coolant pipe if necessary for added clearance.
    4.  

  2.  


CAUTION
When draining coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. On the 1988 325 and the M3 models;
    1. remove the air cleaner and airflow sensor. Then, remove the mounting bolts for the bracket for the air collector and remove it.
    2.  

  2.  
  3. On the 528e models;
    1. Remove the air cleaner and airflow sensor.
    2.  
    3. Disconnect and tag the electrical leads. Remove the bolts and remove the mounting bracket attached to the starter.
    4.  

  4.  
  5. On the 533i and 535i models;
    1. Make sure the engine is cool. Drain some coolant from the cooling system and then remove the expansion tank.
    2.  

  6.  


CAUTION
When draining coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. On 633CSi and 635CSi models;
    1. Make sure the engine is cool and drain some coolant out. Disconnect the heater hose that is near the starter.
    2.  
    3. Depress the brake pedal hard 20 times. Disconnect the power steering line that would otherwise prevent access to the starter.
    4.  
    5. Cut off the straps and remove the solenoid switch insulating cover.
    6.  

  2.  
  3. On the M5 and M6 models;
    1. Remove the exhaust manifold as described in this section.
    2.  
    3. Cut off the straps and remove the solenoid switch insulating cover.
    4.  

  4.  
  5. Remove the starter solenoid wire leads, tagging them for later installation.
  6.  
  7. On 4-cylinder models, disconnect the mounting bracket at the block.
  8.  


CAUTION
When draining coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the accelerator cable holder on automatic transmission equipped vehicles.
  2.  
  3. Unbolt and remove the starter from the engine. On the 325 models the lower nut can be removed more easily from underneath. On late model 5, 7 Series, M5 and M6 models, it may be necessary to use a box wrench with an angled handle to unscrew the main starter mounting bolts. On the 528e, 633CSi and 635CSi, the final mounting bolt must be removed from underneath. On the 1988 325 and the M3. the starter must be pulled out from above.
  4.  

To install:
  1. Install the starter into position and secure with the mounting bolts.
  2.  
  3. Attached any brackets and hoses removed earlier.
  4.  
  5. Connect all wires and secure tightly.
  6.  
  7. Refill and bleed the cooling system and power steering system if any fluid was removed.
  8.  
  9. Where the solenoid switch cover has been unstrapped, reinstall it using new straps.
  10.  
  11. Inspect all wires and make sure none will rub against the body or engine and create an electrical short circuit.
  12.  
  13. Connect the negative battery cable.
  14.  

STARTER OVERHAUL



Brush Replacement

To service brushes, the starter does not need to be removed from the vehicle.

  1. On 4-cylinder starters, remove the support bracket. Remove the 2 screws and remove the dust cap.
  2.  
  3. Remove the lockwasher, shims, and gasket or seal.
  4.  
  5. Unscrew the pole housing through bolts and remove the cap.
  6.  
  7. Lift out the positive side brushes and then remove the brush plate, noting how the housing bolts pass through the locating slits in the plate.
  8.  
  9. Unsolder the brushes from the exterior coil and brush plate and resolder new brush connections in place.
  10.  
  11. Assemble the brushes in place. On 630, 633, and 733 models, check the end-play at the front of the armature. It should be 0.001-0.0.006 inches (0.10-0.15mm). If the play is excessive, correct it by inserting additional shims under the dust cap.
  12.  

Starter Drive Replacement

The starter must be removed and disassembled to replace the starter drive.

A circlip retains the drive gear on the the armature shaft and must be removed before the drive gear can be replaced.

  1. Remove the starter from the vehicle.
  2.  
  3. Remove the field coil wires from the solenoid and remove the solenoid mounting bolts.
  4.  
  5. Disengage the solenoid plunger from the starter drive and remove the solenoid from the starter motor.
  6.  
  7. Remove the small dust cap from the end of the motor.
  8.  
  9. Remove the C-clip, shims and gasket from the end of the starter motor shaft.
  10.  
  11. Remove the two long pole housing screws from the starter housing. Lift off the pole housing cap, the brushes and the brush plate.
  12.  
  13. Remove the intermediate bearing screws and remove the pole housing.
  14.  
  15. Remove the rubber seal and washer from the engaging lever housing.
  16.  
  17. Remove the engaging lever screw and pull the armature out of the drive bearing.
  18.  
  19. Push back the thrust washer or thrust bearing race on the drive pinion end of the motor shaft in order to remove the C-clip retainer.
  20.  
  21. Remove the starter drive pinion and bracket.
  22.  

To install:
  1. Install the starter pinion and bracket. Secure them on the shaft with the thrust washer and C-clip.
  2.  
  3. Lubricate the coarse threads, engaging ring and bearing with high temperature silicone grease.
  4.  
  5. Install the armature and shaft into the drive bearing, making sure that the tabs of the engaging lever are installed over the engaging ring. Lubricate the engaging lever with silicone grease.
  6.  
  7. Install the washer and rubber seal into the engaging lever housing, making sure the tabs on the seal and washer point toward the armature.
  8.  
  9. Position the pole housing so that the groove faces toward the rubber pad and install the pole housing into the drive bearing. Secure the screws with Loctite® No. 270 or equivalent.
  10.  
  11. Check the commutator bearing for looseness and then guide the field coil wires into the rubber seal.
  12.  
  13. Install the pole housing screws through the pole housing cap and locating slots in the brush plate. Install the brushes and pole housing cap on the starter.
  14.  
  15. Check armature axial play is within 0..004-0.006 inches (0.10-0.15mm) for 1970-82 models, 0.004-0.008 inches (0.10-0.20mm) for 1983-88 models. Correct any excessive play with additional shims.
  16.  
  17. Install the end gasket, shims and C-clip on the end of the motor shaft. Install the dust cover on the end of the starter motor (over the shaft, end gasket and shims).
  18.  
  19. Install the solenoid on the starter and attach the field coil wires to the solenoid.
  20.  
  21. Install the starter into the vehicle.
  22.  

SOLENOID REPLACEMENT



This procedure is best done with the starter removed from the vehicle.

  1. With the starter out of the car, disconnect the field coil connection located at the bottom of the solenoid assembly.
  2.  
  3. Unscrew the solenoid mounting screws from the front of the housing. Then, pull the solenoid unit upward to disengage the solenoid plunger from the shift lever, and pull the unit off the starter.
  4.  
  5. Install in the reverse order of removal.
  6.  

 
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