Old diesel starters also suffer from excessive resistance in the windings. As the copper gets old and hot (often from excessive cranking), the wire starts to harden and aquire resistance. This results in low current through the winding and higher current draw on the entire starter because the magnetic field is weaker and the starter turns slower. Eventually gets to bad the car won't start and drags the battery down fast.

Turning and cutting the commutator with new brushes will not fix the problem, so a "cheap" rebuild isn't any good, the starter will still be bad after. A new armature is required.

Some folks will know this as "Chevrolet starter disease" -- starts OK cold, but hot won't crank -- same thing, but on the Chevy V8 it is because the starter is only an inch away from the exhaust manifold and it gets baked.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!