Thread: Broke the small bolt on back of alternator

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Better photo. Broken bolt inside nut. I think it is part of the regulator.

Shell

You have to hook up a wire to that post when you install the alternator, I suspect it wont work without it.

Originally Posted by Dozer2

Is this fixable?

I'm guessing it holds the wire that gives rpm on the dash meter.

Depends on tools available.

Get inside unit to see if replacement with new bolt is easy.

Weld extra stud length to nut and screw back on, touch of loctite.

Drill and tap the broke bolt, drill and tap the shaft of another bolt (cut the head off) of same diameter and pitch. Join the two with another bolt shaft of slightly smaller diameter.

Not sure if an alternator would be affected by direct welding to the broken bolt.

Braze on a new attachment, but again not sure how far heat would travel into the body and affect other joints.

I'd say look for some female or internal allthread.
Dunno what the smallest thread you could easily find, and how small the remaining stud is, but if you still have the broken section of stud, and the nut .. take it to a nut and bolt place and see if they have any.
Alternatively an extra depth nut could achieve the same end, all you want to do is remove the nut remaining on the alt now, fit the allthread/extra depth nut, leave yourself enough female thread on the allthread/long nut to add a stud of your own making .. etc.
In saying that, if you can find a supply place that sells threaded pillars, would be about ideal.
Basically a nut with normal female thread, but one has a stud end. So you fix to the remains of what you have ATM, and it leaves you a stud poking back out past what looks like a nut.

You find these threaded pillars in computers of all sorts that hold a motherboard, above a metal case so that the underside of the PCB board doesn't ground out on the metal case.
The issue may be tho .. the thread doesn't appear to be metric, so finding imperial threaded pillars may be a hard task.

Just had a quick sqizz at mine, and it's similar size to M5, but thread is wrong. I can get about two threads of an M5 bolt onto the nut before it starts to jam up .... so whatever UNF imperial thread size is a close fit to an M5 bolt could be a start point.

If you’re handy and have a section of brass you could do this....

Remove nut that’s there now, the stud attached to the Reg then make similar to drawing

Like what Arthur’s suggesting but wouldn’t protrude out as far??



Lemo

D+ terminal I think, goes to dash warning light. May be required for initial excitation of generator but may well run without it.

Sierraferry can likely comfirm/correct.

Can't access car at present but... have a look at how D2 earth wires attach to the various earth posts. Think they are nuts with wire crimped to a captive washer .... there's probably a name for them. Grab one of those fixings from a wrecker/auto elec.

Thanks everyone for the ideas, these are great suggestions but in the end I wasn't confident enough to mod the remaining bolt stump. The nut is fused to the post so it wouldn't come off, the bolt is too small to drill into, and I'm only new to wiring and auto electrics.

Took it to a local alternator shop who put a new wire at the bottom of the post with a clip for the blue terminal to attach to. Just need to crimp the other end of the blue terminal to the small alternator wire. So it is fixed and future proofed since the nut is now obsolete. Was only $35.

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Thanks again everyone.

Shell