Starter Problems Sorted            by Dave Hall

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There's not much that's worse than sitting in your lovely old VW, turning the key, and ... NOTHING!  It's a very common problem, which often results in being charged for a new starter motor if you entrust the repair to a garage.  Sometimes it may need that, but often it's a much simpler solution than that. Starter Motor - exploded view

Ask yourself these questions:-

Does the motor sometimes work?     Does it sound happy when it does work?  

Does it usually fail after a fast run?     Is the battery as good as it might be?  

Have I undone the wires to the starter motor and cleaned the connections? (IMPORTANT: disconnect the battery first)

If the answer to all these is 'yes', you probably simply need to clean the motor itself.  This is fairly easy!   The reason it causes problems is that the solenoid current has to flow through the motor as well, and the brushes  (B) and commutator get dirty and worn, so not enough current can flow to start the solenoid moving.  This seems to be aggravated by getting hot during a long run, which could be lack of lubrication on the drive pinion.  Of course, changing any part of the system, even cleaning wiring connections etc, may improve the situation for a time.

Cleaning the Commutator and Brushes (some have 2 brushes, some 4)

• disconnect the battery
• remove the starter motor, noting which wires goes where (extra one on some FI cars)
• undo the end cap and long through-bolts, and remove the end cover carefully
• check the brushes are long enough to press firmly on the commutator
• remove the brush plate, carefully removing the brushes as necessary 
• clean the dirty areas on the brushes and commutator (this may need fine sandpaper)
• clean out the slots on the commutator (they should be slightly sunken below the copper segments)
• check the drive pinion operates smoothly (WD40 is good to free it off)
• re-grease the shafts and reassemble the motor parts
• seal the outside against water (I sprayed with Smoothrite and then Waxoyl)
• check the bush in the bell-housing that the motor shaft fits in, and grease it
• re-fit the motor, taking care to tighten nuts, bolts and wires properly.

Enjoy your revitalised starter!  

Starting Motor Trouble Checking


Cause Remedy
Starting motor does not turn when ignition key is being turned    
Switch on the lamps when testing a - Lights do not burn. Loose cables or poor ground connection. Battery run down a - Check battery cables and connections. Test voltage of battery

b - Lights go out when operating the ignition switch. Insufficient current due to loose connections or corroded terminals

b - Clean battery terminals and cable clamps, clean and tighten connections between battery starting motor and ground
  c - Lights go dim when operating the ignition switch. Battery run down

c - Charge battery

  d - Lights stay bright when operating the ignition switch. Make a  jumper contact between terminals 30 and 50 at starting motor: lf the starting motor operates, there is an open circuit in cable 50 to ignition switch, or in cable 30 to lighting switch, or the ignition switch is defective d - Eliminate open circuits, replace defective parts

e - Lights stay bright and plunger  in solenoid switch is pulled when operating the starter. 
Disconnect battery cable from terminal 30 at starting motor and connect it to terminal stud of connector (contact blade). If the starting motor operates, the contacts of the solenoid switch are worn or dirty

e - Replace solenoid switch


Starting motor does not operate when battery cable is directly connected with terminal stud of connector (contact) blade

a - Brushes sticking

b - Brushes worn

c - Weak spring tension. 
     Brushes do not make contact

d - Commutator dirty

e - Commutator rough, pitted, or burned

f - Armature or Field coils defective

a - Clean brushes and guides of brush holders

b - Replace brushes

c - Replace springs

d - Clean commutator

e - Recondition starting motor

f - Overhaul starting motor

Sluggish or slow action of the starting motor

a - Battery run down

b -Insufficient current flow due to loose or corroded connections

c -Brushes sticking

d - Brushes worn

e - Commutator dirty

f - Commutator rough, pitted, or burned

g - Armature or Field coils defective

a - Charge battery

b - Clean battery terminals and cable clamps, tighten connections

c - Clean brushes and guides of brush holders

d - Replace brushes

e - Clean commutator

f - Recondition starting motor

g - Overhaul starting motor

Starting motor is heard to operate, but cranks engine erratically or not at all

a - Drive pinion defective

b - Flywheel gear ring defective

a - Replace drive pinion

b - Replace flywheel or re-machine gear ring

Drive pinion does not move out of mesh

a - Drive pinion or armature shaft dirty or damaged

b - Solenoid switch defective

a -Overhaul starting motor 

b - Replace solenoid switch

Thanks to Volkswagen AG for this extract from a VW Workshop Manual

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