Many of the electrical problems with our trucks can be traced to bad grounds, even problems we don't are.

My stock '49 F-2 with flat six engine started acting up. Started fine when cold but didn't want to start when warmed up. I had to get jump started a couple of times. Since I hadn't given it it's annual tune up I figured that was the cause. Finally the other day I pulled the distributor cap off, cleaned and adjusted the points. Pulled the plugs and cleaned and retapped them and then set the timing. Seemed to start better but still had a little trouble starting when warm. Over the weekend it developed a problem when I pushed the start button nothing happened. Reached under the dash, figuring the switch wasn't grounding, maybe corrosion formed on the contact surfaces. Seemed to help, pushed the button and the starter kicked over. I was busy so I'd fix it later. Yesterday same thing happened but fiddling with the switch didn't do anything. Went to check the battery connections and found the ground strap on the engine was lose. I trie to tighten it but I couldn't tighten it down. Got a new bolt and a new lock washer but still couldn't get it tight. I added two more lock washers and I was able to tighten the strap connection and now the truck starts every time.

I just can't figure out why the connection was lose. It had the same bolt I had in that connection for over 20 years. I've pulled and cleaned the connection numerous times over the years and always tightened down. The bolt hadn't stretched, it was the same length as the new bolt and it was noticeably loose.

 

Bob- the post got small with age the oppsite of me !

 

Bob, what size bolt are you using? I wouldn't be surprised if passing 400+ amps thru it, with threads that are probably dirty inside the head, eroded the tips of the threads. Try a bellhousing bolt near the starter (a through-bolt).

 

Couldn't get it to tighten down, as in the bolt was tight but the cable was still loose? Two additional washers and it tightened up? If so I'd hazard to guess the bolt has always been too long and you've just been lucky that it did find ground all these years.

 

Very true Bob! Two years ago my truck was at my brother-in-law's place as he was trying to figure out why it wasn't running well. Long story short it was worn out distributor. Come on after only 60 years! You'd think they last longer!

Anyhow, it started hard when warm. I thought it can't be dirty grounds and connections! I just put new cables in when I had my truck painted..... well that was back in 1999. So I took off all the electrical connections and cleaned them up. They had become corroded. That fixed the problem.

 

Sorry in advance as I know this will stir up controversy but this is one reason why OEMs went to 12v. It is easier to overcome slight resistance.

 

There was nothing wrong with the bolt I replace other than being a little dirty. The battery cable was obviously loose, swing back and forth with some up and down play. This bolt had been there for years. The lock washer was flattened, like most do. The new bolt was the exact same length. I'm sure I would have noticed this the many times I've cleaned the battery cables over the years. When I noticed it was loose the first thing I did was try to tighten it, acted like it was bottomed out but still loose. I thought the bolt might have stretched but again, the new one was the same length, the shortest bolts in my bin of new bolts.