Removing broken bolt.

[Pink_Floyd]

I have snapped of one of the bolts that bolt the bell housing to the block. The bolt is seized solid. Tried Plus Gas and other penetrating oils but to no avail. In the picture the stud has a red outline to make it easier to see. There is about 8mm sticking out. Tried arc welding a nut to it but the weld takes to the nut but not the stud.

Last resort is to drill and re-tap it. But before then, has anyone got any bright ideas.
Thanks.

[Zumbruk]

A friend of mine had several exhaust manifold studs removed from his Lotus Esprit engine by a visiting spark erosion service. He's in Hong Kong at the moment, so it might take a while for me to find out how he found the chap, or you might try and call some of the services a Google for "mobile spark erosion" finds...

This looks like the kind of thing;

http://www.sparkeroding.co.uk/

Edited by Zumbruk on Tuesday 11th November 20:46

[Chimjunkie]

Would minus one bolt affect the mounting of the bellhousing? The bit remaining is acting as a stud which may be useful in the minus one bolt scenario...

[spend]

Is the stud stainless?

[GreenV8S]

spend said:

Is the stud stainless?

If it is, you're never getting it out. Would never have been stainless originally though, and who in their right mind would ever have replaced it with stainless?

I think your best bet would be read through PumaRacing's web site where he describes how to remove seized studs/broken bolts. If none of those techniques will shift it then you might be looking at spark erosion I suppose but that sounds expensive to me.

[brogenville]

I would give these a go:

http://www.machinemart.co.uk/shop/product/details/...

I'm told they work very well.

[mb450]

brogenville said:

I would give these a go:

http://www.machinemart.co.uk/shop/product/details/...

I'm told they work very well.

They are good - but if the bolt is stuck fast you might just end up sheering it off at the casing if you use them.

[2Munkys]

There's not much left of that stud from which to gain purchase. As you have access I think I'd be tempted to flatten it back somewhat and carefully pilot drill then use subsequently larger bits. Quite often (but not always) before the bit size approaches that of the threads the binding will be alleviated to a point at which the remains of the stud can be removed with a pair of flat-nose. I'm sure you can get it out and if you cause some damage you have access to make an effective repair by more than one means.

[scoule]

Have you tried heat? The alloy should expand more than the stud and it might come out with mole grips or those extractors from machine mart in conjunction with heat?

[Pink_Floyd]

scoule said:

Have you tried heat?

That is the next thing to try, planning on using oxy torch or similar to heat it up, just got to get the engine to the torch or the torch to the engine, torch is several miles away.