4630 Negative battery cable termination point

Just picked up a 4630 last week, went to crank it and noticed sparks from negative battery cable that is terminated on a stud coming out of the back of the starter. This stud gets warm and sparks are seen while cranking. Stud is tight and cable is clean. Not sure what is going on but I notice my 2600 battery negative cable is terminated through one of the 3 bolts that hold the starter to the block. Should I just move my 4630 to one of these bolts like my 2600 and move on or is there a reason the negative cable should be terminated at this stud coming out of the back of the starter? For the record, the starter seemed strong and turned over the engine well but these sparks and heat bother me. Thanks for any information or suggestions.
 
"Stud is tight and cable is clean."

If those were both true you wouldn't be seeing sparks and heating.

Typically, though, when the battery ground cable goes to a terminal stud on the back of the starter (which gives a more direct ground path to the negative brushholders) there's also a ground jumper from that terminal to the engine block or tractor chassis.

That would have more to do with the operation of the charging system and battery powered accessories than with the operation of the starter, IMHO.
 
I agree with Bob regarding the sparks and heat at the ground lug. Move the cable end to a starter mount bolt.
 
Sparks and heat mean you have a loose connection. Even though the cable is tight to the stud, the stud is not tight against the cover from the inside. Essentially that stud is simply a bolt coming through the cover from the inside. Over time, the steel bolt has corroded against the aluminum cover, causing that connection to come loose.

The proper repair is to remove the end cover of the starter and clean up that bad connection, which is very easy to do, but most people simply move the ground cable over to one of the 3 mounting bolts, and everything works just fine. It's six one way, half-dozen the other.
 
Bern explained it perfectly... My personal preference is to remove the end cap and clean it... then install a new bolt/stud... it's actually
just a bolt. You could move the cable back to the mounting bolts but I'm not sure that will ultimately gain you anything.

Rod
 
To the OP: Moving the cable to the starter mounting bolt is a short term fix that usually ends up being a permanent fix 99% of the time. As noted, the proper repair is to clean up the stud in the cover. This gives the absolute best ground path (i.e. less resistance) for the brushes in the starter. Less resistance equals more current flow and a faster turning engine.
 
I think I will remove the back cover off the starter and replace the bolt/stud as a fix. I took the starter off last night and I promise you, the stud is tight as tight can be and the cable end is clean and shiny. I assume I will find a corroded joint between the bolt head and the cover on the inside of the starter when I remove the cover causing me this issue. Anyway, when I remove the cover will the brushes come with it? If so, is getting this cover back on straightforward? I'm sure it's uneventful but I liked to know what I'm getting into before I jump off in it. Thanks guys.
 
Remove ALL of the bolts from the rear cover before removing it (except the stud). This will ensure that the brush holders stay put. If you align the cover back on reinstallation, the bolts holes should all line back up.
 
Took the back cover off. Stud was tight and no corrosion. I replace it but I'm not so sure I agree that grounding to this back cover that is aluminum is the best place to ground. There is a rubber gasket between this cover and the stater housing as well that contributes to my doubt. After looking at it close between the aluminum and the rubber gasket there seems to be a very poor ground path in my opinion. I posted pics so you can see what it looks like. Maybe some of these starters had a steel back plate is why most say it's the best place to ground? I 'm confused. I am going to try it there but any more sparks and or abnormal heat and I will try grounding at a bolt on the starter flange at the block.
 
Stop and think about this for a minute... two of the brushes terminate on the brush holder. The brush holder is bolted to the end plate. The
ground stud is in the end plate. That IS the ground path. If you bolt the ground cable to a starter mounting bolt, it will still ground...
but the path is less direct... as it then passes through the starter case bolts... and would have to work around the seal you're worried
about. Either way it will ground.
If you've got a starter that is still making smoke and spark after you've cleaned the grounds... then the options you've got left are a bad
solenoid/switch (usually seen by a starter that is poor to pull in), bad brushes... or bad windings. Often times new brushes, a good
cleaning... and new cone and nose bushings will renew those starters to near 100%. Seldom do windings or armetures fail in the Lucas M50. If
you have an asian knock-off... all bets are off.

Rod
 
I have the original Lucas starter not an Asian knock off. I haven't tried the starter since I took it apart and replaced the stud. I'll try it this weekend. I just saw nothing that indicated anything was wrong at all. The original stud (bolt) was not corroded at all but it sparked etc where the ground cable connected to it. We'll see but, by the looks of the inside of this starter and knowing the low hour history of this tractor I wouldn't expect anything wrong with the starter. I'll report back when I can try it again. Thanks.
 
A spark is caused by a loose or broken connection, period. You say that everything looks clean and tight, but something is amiss here.

The only other thing I could think of is that you're seeing the natural sparking action of the brushes on the commutator segments. However, the gasket on the end cover would have to be missing, and maybe even a chunk missing out of the cover before you'd see it.

OR, something is shooting out of the solenoid in the direction of the ground stud, again, caused by a loose connection.
 
I took the end off the starter and the original bolt was dry (no oil or any other residual moisture) and there was no signs of any arcing or anything at all amiss. The bolt was tight as it should be. There was simple nothing obvious wrong. But, I found an old bolt in my stash just like it, replaced it and the nut and I have no more arcing at all... very strange deal but my starter is 100 percent now.

Thanks guys.
 

Most likely the problem was the nut, not the bolt.
I've seen it happen before, the nut gets rusty and looses connection, we'd replace the nut with a new shinny one and everything would go back to working properly.
After all it's the nut that tightens up against the cable on those starters, not the bolt.
 

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