Stovebolt.com Forums The Shop Area The Electrical Bay Starting question

Fired up my ‘51 3100 12v conversion with a ‘55 235 in it today in -5 weather. Starter I assume is 6v. Cold made it slow but eventually started. Drove to coffee 5 miles away. About an hour later tried to start it but nothing. Not even the clicking starter of a dead battery ( it was fine). Pushed the truck down the road with help and popped the clutch and got home. Before I dig into it, what could be the most common causes? I’m guessing bad switch, solenoid, or starter.

Dirty battery cable connections would be my first check. No, "They look good" is not the right answer. Remove both battery cables, shine up the battery posts with a wire brush, and scrape the inside of the cable clamps clean with a pocketknife. There's also a specific tool for cleaning battery connections that combines a male and female brush into one tool at virtually every auto parts store.
Jerry

My "go to" for most electrical issues is "check and clean your grounds".

So looked at the starter switch. A bit dirty so shined it up. Then opened up the starter. Very dirty. Cleaned it but noticed something. The pivot for the brushes ( 4 of them) on 2 of them seems to have a small weld that prevents it from contacting the commutator. Seems frozen so they don’t spring close. Is that stock? Two of them work fine- springs work to hold it in place.

They should all have pressure on the commutator.
George

So looked at the two brush pivots. Someone soldered the fixed open. Heated the pivot with a solder iron and they loosened. All four now contact the commutator. Put the starter back in and it starts strongly now. I guess a lot of cleaning and troubleshooting really works. Thanks for the ideas.

Ive asked several mechanic friends why two of the four brush bracket pivots would be soldered open. Any ideas?

Just an idea and I don't know if this is your situation.
If the brushes are severely worn down, the starter is designed to prevent the holders from making contact with the armature and causing serious damage.
When a starter stops working from worn brushes it's maintenance time.
Burnish the armature, do some cleaning, check/lube bushings, replace contacts and replace the brushes.

Cleaned armature, lubed, cleaned contacts. Brushes had plenty to life left. It now runs great. A mystery. Only thing I can think of is the PO was planing on converting to 12v and this starter is 6v so maybe he though only 2 of the 4 brushes would reduce voltage (??) so he soldered the two negative brush’s pivots so they wouldn’t contact the commutator.

I wonder how it started when you went for coffee, with two negative brushes soldered?