It should never be attempted until a failed bench test. Your recommendation of tapping the starter at early stage might have ruined his "still ok" starter.

 

A little FYI,

Having rebuilt a few starters, that tapping helped, all that happens if tapping helps is, the brushes got stuck and tapping helped them slide down to make good contact with the commutator on the armature..

Lets face it,if we are going to take it off to have a bench test done , you might as well replace it then, because some can be a real PITA to R&R.

 

Well said @hanky

 

I agree that the starter was heading for replacement (based on the troubleshooting that was done).

I will add though - The solenoid powering the starter motor can get pitted contacts, or the solenoid shaft itself can drag. Sometimes very gentle tapping on the solenoid itself can help, if it is experiencing these issues. Doing this when you are stranded, or when you have already identified a non-functioning starter, is not a big risk at all, especially when you do it with a gentle tap(s). Excess force of course obviously can cause damage. This is why I said to tap the solenoid (OP quoted it in post #38).

Brushes hanging up in the starter motor is probably much more common (and the general idea of tapping on the starter motor is to free the brushes - as stated above), but excess force can be destructive here also. The brittle magnets are in the starter motor, not the solenoid. So if you want to tap on the motor, tap where the brushes are, not where the magnets are.....

You Tube

Just my 2 cents.

 

Well now I'm really hosed!
Bought a new starter but before putting it in I took the old one into the parts store and they bench tested it on their machine and it works.
So I'm mystified why when it was all put together and I shorted the contacts on the fender mounted relay all I got was a click and no crank back when I started this mystery search. Tearing my hair out!!!

 

Sent you a PM.

 

You said you shorted the fender starter solenoid, check the range sensor fuse the 15A and see if it's blown. One thing I didn't mention in this entire thread on what that 15A really do and I will mention it briefly now that when at rest (key out or not in start position) the trigger wire will have continuity to chassis ground when the solenoid is not energized. When you crank and when the fender solenoid is not working, the trigger wire will still get around signal and that F5 (15A range sensor) fuse will be blown immediately. So check and see if F5 fuse is still good or not. Everytime the range sensor fuse keeps blowing that's a sign of a bad fender solenoid.
As far as all the cables, the terminal on one end can be brand new or cleaned with wire brush like brand new, the cable itself, especially after the terminal, when it's bad you just have to cut it down and shorten it until you see all bare copper wires in golden brown color. If you shorten it by more than 3 inches and it still doesn't look good, it's time to replace the entire cable. Doesn't matter it's the positive or negative cables.
On old trucks nothing will be perfect. You said you are going to sell this truck so don't beautify all of them for a car show whether or not you are keeping or selling it.

 

Think about this,


The solenoid on the fender well gets it's ground through the mounting bracket on the sheet metal.
The coil of wire inside that solenoid has to have a ground to operate.
The other end of that coil gets battery power, 12 volts, when ever the key is turned to start position.That is what energizes the solenoid to close.and supply battery power to the starter.
If that "trigger wire gets 12 volt power when the key is in start position, it should blow the fuse mentioned, and this just does not happen.
The right way to check that wire for any short to ground is isolate it !

SO ,,,,Applying power externally by jumping at the solenoid is the same as turning the key to start.


I believe the time has come for a little homework in basic electricity.

 

Well I put the old starter back in since it passed a bench test and don't ask me what's different but this time it worked.... finally 😀 thanks to all you fine gentlemen for all your help, advice, and education.

 

The motor brushes were stuck, or solenoid contacts were not making solid contact (shaft sticking). Sometimes the process of removing the starter, setting it down on the ground or table, etc will contribute to the electrical components getting freed up or making better contact (per the PM). Glad you re-installed the old one for "one last attempt", and thanks for posting the conclusion. Hope it gets you through the selling process.