'92 Taurus Wagon Not Turning Over

The history is: 1+ month ago the car started acting up; about every 4th time it wouldn't turn over, though the lights and other electrical stuff worked. There was corrosion on the battery terminals, so I concluded
that either they weren't getting good contact, or that the battery was going <no starts seemed to occur after the car had been driven a couple of places>. Cleaned battery terminals and problem went away for several days. Re-occured, so I bought new battery. Problem could be worked around by thumping the terminals <not too hard>. Didn't have a chance to put new battery in <too busy>, and then the problem went away completly, so last week I took the battery back <needed the money>. Yesterday problem returned. Car didn't crank; rapped smartly on top of the battery leads with fist, car started normally. Today car wouldn't turn over for wife, her messing with terminals didn't fix. When I got home I rapped on the terminals again and the car cranked weakly, then started. Next time I shut it off it wouldn't crank at all. Cleaned terminals again, no crank. Replaced battery, still no crank. All electrics working, radio, headlights, etc. Headlights do not dim when attempting to crank. Both batteries show 12+ volts. When attempting to start I can hear the solenoid clicking, but the starter motor doesn't engage. Rapping on both with pliers improved reaction to crank attempt marginally <*click* to *click-errrrrrrr*- no crank though. I'm going to pull the starter to have it tested as soon as the hurricane lets me, but as this is my first Ford, I wanted to poll the experts to see if there is something else that might be going on? Ignition modules? Starter relays? What is confusing me is that if it's the starter, why did messing with the battery make any difference, unless it's the leads themselves? Seems to me the negative clamp is a little sloppy, and even when cranked tight doesn't seem to grab much of the post, but even so, it's nice and tight- I've seen much worse work fine.
Sorry for the long post, any help appreciated.
Dragon
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Your cables might be corroded, might check the voltage on the posts during attempted cranking, if it barely changes then you should move towards the starter following the cables to their terminus.

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Voltage drops about 3/10's, not nearly what it should, IMO. I've checked the other ends of the cables and all of those connectors are tight and undamaged. I did notice that the starter, which sits on the front of the engine, has a lot of dirt build up, leading me to wonder if it's also getting a lot of water in it <lotsa rain here in PA over the last few months>.
Thanks for your help.
On Thu, 18 Sep 2003 05:06:11 GMT, "The Bathtub Admiral"

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snipped-for-privacy@specified.com wrote:

stay with the battery, thats the problem, forget about the starter for now: go to auto zone and buy a $1.98 battery terminal brush.. then take off the battery terminals and use the battery terminal brush to clean up the inside of the terminal and the top of the post of the battery where the termnials are attached.. Hitting on them with Pliers is not gonna correct the problem(even if it gets it to start). put the terminals back on and the problem is gone... pretty good fix for $2.00. or you might just need two new battery terminals(cost about $1.98 each)....
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Battery post brush was the first thing I bought, brought terminals and posts to a shine each time I cleaned them. Clamps currently installed with felt washers underneath them, and anti-corrosive applied to exterior of clamps and posts <not at mating surfaces>. I was looking for some dielectric grease to put on the posts but Wal-mart didn't sell any. Do you think that might help?
Thanks for your help.

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The problem could be the solenoid contacts are not making a good contact or a bad connection or cable. To check the connections I always disable the ignition so the car will not start. Have someone start the car and check for voltage drop at differnt places until you find the problem. A voltmeter or a multimeter set to voltage setting will tell you the difference in voltage between two points. You have to have the ciruit under load (have someone hit the starter). These are good articles that explain how to check for voltage drops:
http://www.labscopes.com/pg08.htm
http://www.fluke.com/application_notes/automotive/circuit.asp?AGID=1&SID 3
wrote:

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Sounds like the solenoid to me. It's a fifteen dollar part. If it isn't the source of the current problem, at eleven years it was getting ready to be the source of some problem.
snipped-for-privacy@specified.com wrote:

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Thanks to all who responded- I removed the starter this morning and took it apart looking for obvious defects. I didn't need to look much further than the hunks of copper that fell out of it when I seperated the casing halves- 2 rotor brushes were wiped completly out, and one rotor bar was melted and torn out of it's mounting.
New starter in and it works fine now.
Dragon
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