Have received many useful tips over the years from this forum.
Think this may be of help to others someday:

No start, no click, good battery, 12V and 6V at solenoid with key in start position, 12V at starter post, good ground.
Only 6 bolts need to be removed: 2 on starter, 2 on clutch slave (don't remove hydraulic line-won't have to bleed), 2 on flexible hydraulic hose bracket.
Follow these well illustrated instructions(thanks to Gregory Bender):

http://www.thisoldtractor.com/gtbend...ir_-bosch-.htm

4 Brushes - $10
Bushings - $1.72 each (Rock auto)

 

Since you heard no "click", the primary issue is the solenoid. The brushes and bushings may be fine. Hopefully the solenoid is fixed by a simple cleanup of the contacts as shown in your link (thanks for that, should I ever need it).

 

That's what I figured also.
But since it is almost thirty yrs old and out thought I might as well replace brushes and bushings as well.
Anyone know if these have a tendency to wear out. Would be good to know so I can just fix the solenoid and not bother opening the motor.

 

Certainly a good idea while you have it out. Mine is still original at 245K miles. Let us know what kind of condition the brushes and commutator are in.

 

The bushings are usually sintered bronze with integral lubricant. This means that the bushing is not really solid, but is made of little bronze ***** mashed together, with tiny spaces between the ***** that are filled with oil.

If you reuse a bushing, put a few ounces of 20W-50 synthetic oil in a small cat food can or similar vessel, and make sure that the oil will cover the bushing. Simmer the bushing for a few moments, being careful to avoid getting things hot enough to cause a fire. (Do this somewhere besides the kitchen stove if you enjoy sleeping indoors and having your meals prepared by the stove's owner.) Let the bushing cool completely while still submerged in the oil. This will refill the pores in the bushing.

 

Good write up. One small correction though. This starter doesn't have a bendix. A bendix uses inertia and a worm gear to push the starter drive gear into the flywheel. What he's referring to is simply the starter drive gear.

 

Will have to change the title of my post to "How to buy a Porsche starter"

We were correct in assuming that the problem was the solenoid - the solenoid coil is shorted out. The contacts show no wear or pitting.

However, am surprised that I didn't have trouble yrs ago. The motor was loaded with graphite dust, and the commutator is actually worn down to a concave shape with the insulation between bars gone or filled with graphite.
The pinion and ring gear show no wear. ('83 with 91,000miles)

To Auto-zone for rebuilt starter with lifetime warranty $82.

Thanks for the responses.