Stripped M8 Thread on Alternator Body

nigelmercier

nigelmercier

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nigelmercier said:
I've just changed my Alternator Belt Layout...
Click to expand...
Some time ago the M8 thread at the top of the (aluminium?) body of my alternator stripped. I've been using a long screw and a back-nut, but now is the time for a proper repair.

Balmar-901100-Top-Bracket-035_zpshhueb9ho.png~original


I'm not sure a Heli-Coil is what I need, is there an STI that will insert from the rear, where the nut is?
 
What is wrong with your bolt and nut approach. To me that is looking like a proper repair.
As long as it works and there are no issues like unable to reach the nut etc. I dont see any need to change it.

Cheers
Christoph
 
Are you concerned there is not much metal around it?
If so, why take away more metal, when the nut and bolt works OK?
 
Skipper_Christoph said:
What is wrong with your bolt and nut approach. To me that is looking like a proper repair.
As long as it works and there are no issues like unable to reach the nut etc. I dont see any need to change it.

Cheers
Christoph
Click to expand...

Agree, but if you insist, helicoil is best way.
Without checking, I'm surprised it's only M8, I thought they were normally M10. Is there clearance to drill out and tap as an alternative? In your photo the bracket slot looks wide relative to the bolt.
 
nigelmercier said:
Some time ago the M8 thread at the top of the (aluminium?) body of my alternator stripped. I've been using a long screw and a back-nut, but now is the time for a proper repair.

Balmar-901100-Top-Bracket-035_zpshhueb9ho.png~original


I'm not sure a Heli-Coil is what I need, is there an STI that will insert from the rear, where the nut is?
Click to expand...

The slot in the adjustment looks wider than 8mm, Could a M10 setscrew of through the slot, if it can you could tap out the stripped M8 to M10 and fit a M10 clamping screw.
 
Weld a bent washer to the nut that engages with the alternator body preventing it to turn.Voilá,one handed operation.
That's what I'd do but I have a tendency to weld everything:)
 
Where there is sufficient meat I have drilled out and for a tight interference fit and used a rivnut press fitted with the flange to the rear, it's very simple to do.
 
Rogershaw said:
The slot in the adjustment looks wider than 8mm, Could a M10 setscrew of through the slot, if it can you could tap out the stripped M8 to M10 and fit a M10 clamping screw.
Click to expand...
I have a plan to make a turnbuckle adjuster, using M8 Kart Track-Rod Ends and a length of Hex Bar tapped LH/RH. I have already bought the parts, the drill bits, and the taps.

This may all be immaterial, as I managed to blow up the alternator last night.
 

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nigelmercier said:
I have a plan to make a turnbuckle adjuster, using M8 Kart Track-Rod Ends and a length of Hex Bar tapped LH/RH. I have already bought the parts, the drill bits, and the taps.

This may all be immaterial, as I managed to blow up the alternator last night.
Click to expand...

Sorry to hear about the alternator Nigel. What happened?

I like your LH/RH threaded tie bar idea.

I needed to adjust the threaded tie bar with a swivel joint on each end which connects my autopilot position sensor to the rudder assembly. No problem ... just loosen off the locknuts by the swivels at either end and turn the threaded bar a couple of turns.

No way! The bar and the two swivels are all conventionally threaded so when you turn the bar one swivel moves in and the other swivel moves out and you are back where you started! Not sure what the point of that is but to adjust the length you have to remove the tie bar. :confused:

Good luck with the alternator repairs.

Sorry Nigel - just caught up with latest post. What a bu**er!

Richard
 
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nigelmercier said:
I have a plan to make a turnbuckle adjuster, using M8 Kart Track-Rod Ends and a length of Hex Bar tapped LH/RH. I have already bought the parts, the drill bits, and the taps.

This may all be immaterial, as I managed to blow up the alternator last night.
Click to expand...

Why not just use a stainless rigging screw of a pre made body.

http://www.tecni-cable.co.uk/M8-A4-...-Rigging-Screw-Body-Standard-Type-301-213-008


Any auto electrician should be able to repair your alternator.

I also have a 2 alternator setup like you but crankshaft had a 3 groove pulley so I have 3 belts 2 alternators and water pump. The water pump belt is tensioned using a jockey pulley tightened with a small rigging screw.
 
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Like the idea of a rigging screw and trackrod ends as a replacement for the conventional method of adjusting the alternator belt tension. The adjustment on my Perkins 4108 is a bit fiddly and this would make it a lot easier. Thanks for the idea.
 
RichardS said:
Sorry to hear about the alternator Nigel. What happened?
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I'm almost to embarrassed to say. I had covered the positive lead with a bit of tubing and was offering up one of the ancillary negative leads to replace the crimp terminal. In doing so, the whole bundle shifted, the tube slipped off the positive, and the leads contacted the alternator the wrong way round. There was a bang, and both leads were briefly welded in place. Yes, I know the power should have been disconnected, but that makes the engine bay lighting go out.
 
neil1967 said:
Like the idea of a rigging screw and trackrod ends as a replacement for the conventional method of adjusting the alternator belt tension. The adjustment on my Perkins 4108 is a bit fiddly and this would make it a lot easier. Thanks for the idea.
Click to expand...

Having second thoughts here, bit of 8mm stainless under dynamic compression loads for years. Hmm. Might stick with what there is, not exactly something which gets much adjustment anyway. 10mm maybe..... ?
 
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