My altenator has fallen off. Bolts have sheared off flush!

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firstascent2002

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Hi guys,

I'm cruising up and down the entrance to plymouth sound, waiting for there to be enough water to take me up to weir quay. I don't want to stop the engine or use the electric windlass as the altenator is sitting on the cabin floor. The pivot bolt that holds is in place to allow tensioning on the slide has sheared off flush with the engine block!

What the hell am I going to do? Can a 1 cm stainless bolt be drilled out? Can it be done in situ or is the engine going to have to come out of the boat. If the engine has to come out then what else should I have done at the same time? It's a volvo 2002 18 hp dating from 1989. Had a top end rebuild in 2003 and until today has never put a foot wrong.

please tell me that the yard can drill the bolt out in place??!!

hope other peoples weekends are going better. We also had a galley fire when the taylors started to drip paraffin freely in to the oven. Until today that has also never put a foot wrong. They say things come in threes too...god help me...J
 
You can drill the bolt and use a bolt extractor, it will probably come out, if its not corroded in place, if it is stainless, it is maybe OK.
There are other sneaky ways of getting it out, but I'm sure a decent yard/engine man will be able to do it.
 
The main thing is to get the boat to a secure place.

The remains of the bolt can be extracted in a variety of ways; it is not a big deal, although it might appear to be one from where you are steering at this time!

If there is electricity at the quay, it is usually possible to strike the centre of the sheared bolt with the tip of an electrode of an ordinary stick welder. The momentary heat that is generated is usually sufficient to break the bond.

If it does not play ball, the bolt can be (1) drilled 6mm and extracted with an easy-out (2) drilled 8mm - very carefully down the centre - and the bolt threads collapsed away from the female threads, or, (3) drilled oversize for the insertion of an M10 helicoil.

Don't be bullied into believing that it is a major operation.
 
How about welding a big washer on to whatever is left of the stud. Then, weld a nut onto the washer. Of course of all this depends if it is possible to get in to weld.

Have fun !!
 
Sharp centre punch will usuall do it , the alternator bold will not (should) not be tight in the thread as it should not 'bottom out', the bolt is tight as it clamps the alternator bracket to the engine, if the bracket is off bolt 'should' not be to tight. I have done this outside Falmouth same thing, alternator fell off bolt flush with engine, I used a sharp centre punch or the edge of a cold chisel to undo it. Be careful not to 'spread it ' though.
If all else fails easy outs are a good bet in this situation but you will be b****gerd if you break that in the block
Good luck
 
Boat's on the moring now...Managed to find that my saildrive is weeping oil from the filler cap or the dip stick as a side effect of staring at the alternator for so long! Anyway, thanks for the reassurance that this is a job that "can be done"

Kind regards

J
 
Yes an Easy Out is the best hope.
An easy out is like a wood screw or self tapping screw with a very course thread (about 1 turn to the inch) that is left handed thread and with sharp cutting edges.
You drill a hole in the bolt of a suitable size ie 6mm then screw the easy out in anti clockwise. When this bites into the bolt metal your unscrewing action will remove the broken bolt and or tighten up the easy out grip on the bolt. It is made of very hard steel but can be snapped off with over load so the bolt must be only in with normal tightness. If it is corroded in then this must be freed with heat, hammer and lubrication.

It is not a difficult job providing you can get access and get a drill with enough pressure to drill into the stainless bolt.

good luck olewill
 
Re: My altenator has fallen off. Bolts have sheared off flush!

I had exactly the same situation a couple of years ago with a VP 2003. I drilled into the remaining part of the bolt, and then got a torx head screwdriver which then easily turned the remains and out it came. I thought it would be a lot harder than it was, but of course the remaining part is under no tension, so was easy to unscrew - assuming that it hadn't bottomed out in the hole in the block - which it shouldn't have or the alternator wouldn't have been fastened correctly.
 
Re: My altenator has fallen off. Bolts have sheared off flush!

I once watched with admiration as a local marine engineer in Stromness (Orkney) welded an old Allen key to a broken bit of exhaust manifold stud several mm inside the threaded hole in the cylinder head. A very steady hand! The fact that he set the boat on fire as part of the operation seemed a small price to pay.
 
Re: My altenator has fallen off. Bolts have sheared off flush!

A small tip worth doing is when you drill the old SS screw start with a smaller drill say 3.5mm or smaller as a pilot it will cut easier than a 6mm in one go.
 
Re: My altenator has fallen off. Bolts have sheared off flush!

Use a slow COBALT drill bit for stainless steel, drill a pilot hole after centre punching, enlarge hole and use an easy out extractor, you can but those in sets. Basically a left handed screw jams in the hole and unscrews the broken bit. However, drill diameter no more than half the bolt diameter because otherwise there is a risk that too large an easy out will expand the drilled bolt and jam it. Easy-out stud extractors come in a set, Halfords etc or good accessories factors if not your chandlery. It's the drill bit that is important here. Must be cobalt tipped.
 
Re: My altenator has fallen off. Bolts have sheared off flush!

I love this Forum, Thans for so many helpful returns in such a short space of time

Kind regards

J
 
The same happened to me on a VP 2030, it was easy getting the stub out, I just tapped it round a turn with a screwdriver, it then came out by hand. I replaced with a std stainless bolt from the chandelry
Stu
 
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