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With a less than optimal 12.2 volts at the battery terminals and the bendix drive at the starter failing to pop and engage the flywheel, would battery charge be a likely cause of such a failure? Or would the fact that the starter motor runs, minus bendix action, conclude that the battery charge is not the cause; rather, the starter itself, such as a stuck bendix drive or worn brushes?

Note that the vehicle in question, a 1989 Town Car, has good continuity throughout the electrical system to the starter, and the solenoid is good.

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You're mentioning a solenoid. Are you sure it's a bendix drive? It sounds a lot more like a faulty sprag clutch on a regular starter. –  kahbou Nov 25 '13 at 17:53
    
The 89 TC solenoid is mounted remotely on the fender. When directly applying 12 volts to it, via jumping it with a screwdriver, it works, powering the starter motor; however, the bendix drive (or whatever type of clutch mechanism it is called officially—sprag clutch? not sure)—it does not engage. –  PJS1987 Nov 26 '13 at 4:09
    
If there's no solenoid on the starter I have no idea. On every starter that I've dealt with there's a solenoid on the starter itself that both pushes the pinion into the flywheel teeth and closes the circuit for the starter itself. The sprag clutch is in there to stop the starter from overrunning (and charging the battery) once the engine starts. It kind of sounds like this is the kind of starter cinelli is talking about, but I'd had to question his/her advice on so little information. I've never dealt with or seen a Bendix before--good luck. –  kahbou Nov 26 '13 at 8:05
    
The over run clutch on a pre-engaged starter motor is there to prevent the flywheel ring gear spinning the stater motor at such a high speed that it is destroyed –  Allan Osborne Nov 26 '13 at 20:45

2 Answers 2

up vote 3 down vote accepted

A less than optimal battery and a functioning solenoid you would at least get the bendix to actuate. The less than optimal battery, would not supply enough power to have the starter actually rotate the engine.

This is usually audiable with a quickly repeating clicking type noise and other times by one "click" [and usually the driver cussing and pounding on the steering wheel finally ending his/her rant by resting their forehead on the top of the wheel].

If the starter is just simply free-wheeling (spinning without first mating with the flywheel) then you're looking at a starter replacement or rebuild, whichever you prefer.

Regardless while you're taking everything apart since you'll be disconnecting the battery anyways might as well check the water/acid level, top it off and give it a solid charge so it's good to go when you get it all put back together.

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This was basically the clarification I needed and confirmed my suspicions. Thank you. –  PJS1987 Nov 26 '13 at 4:12

It is unusual to hear of a bendix starter motor now days. Most starter motors are known as 'pre-engaged' and have a starter 'pinion' operated by the solonoid. When you turn the key to start with a bendix starter motor, the motor armature spins and the inertia of the bendix causes it to wind itself along its helix, engage with the flywheeel ring gear and then rotate the engine. Reasons for poor or non-operation would be low/flat battery, poor earth/power at the motor, wear on the bendix assembly, disconnection of the bendix leaving it 'floating' on the starter, oil from a crankshaft rear seal leaking, clutch dust, and metal 'dust' from wear and tear. Another failure associated with the starter motor is that the engine, because of the compressions in the engine, always comes to rest in the same few places. With a bendix motor, the repeated impacting into the ring gear at these areas knocks out the ring gear teeth to the point where the bendix can no longer engage and turn the engine. When you check the bendix, check the ring gear. The pre-engaged motor avoids all of this by engaging its pinion first.

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