Best way to remove a broken stud?

This is a question rather than a tip. On my Villiers Mk 15 both of the exhaust studs are broken. There is a little bit showing but they won't budge with pipe pliers. My stud extractor only goes down to 6mm and these are about 3mm. I know I could drill them out but I expect I am going to break a lot of small drills in trying. Anyone got any tips or suggestions that have worked in the past?

Dan sorry to say it's not going to be easy no matter which way you do it. You need to get some releasing fluid on (plus gas not wd40) as it sounds there in tight and let it soak in. With it being exhaust you might have to get heat on to the surrounding area (not the stud) to try and move them. With them being so thin it's a problem, you might have to get another block.

Stu.

same here Dan..its going to be a delicate job..good luck with it..

Hi Dan, sounds like they need drilling out and then re tap the thread, if theres enough bolt left to get a very and i mean very good pair of mole grips on some gentle heat and duck oil is very good then ease them out with the grips, when doing this try tightening the studs slightly first before trying to undo it will break the rust off,
Cheers ian

heat is your friend .... Two ways either with a blowtorch , oxy acetylene etc and get some mole grips on it .. Or Get a nut thats bigger than the stud , split it over the top and with a welder puddle weld it on but do it on a high amperage , then let it cool ! this is a must ... then try to ease it out .... works a treat ...

matt

villiers studs are not hardened or tempered
so drilling will be easier than you would normally have to do on other engines
the ones on the villiers ive done
drill a really small hole in the dead center of the stud, and send some easing oil down there till its full
unless your un looky and the casting is drilled through to the exhurst port so add oil to the back of the stud from there
if it still wont move the next day,then work your way up your drill bits untill the stud starts to be thin, add heat and give it a turn
it should come out easy
FINGERS CROSSED FOR YOU kev

Hi Boss. Big problem with drilling is likelyhood of damaging thread if off centre. I have had broken studs removed using a spark-erosion machine. This floods the component with a fluid and slowly feeds an electrode into the stud whilst pulsing a hot spark. This is a pretty basic explanation of a very tricky machine. the end result is a clean hole with perfect thread. Cheers, Derb.

Never heard of that method Derb, sounds interesting.

Stu.

I think I'll try the welding a nut on first whilst I've still got some stud exposed. I expect that this will shear the stud off at the cylinder head so I'll give it a go at drilling if that happens. Failing that, anyone got a spark erosion machine ???

Try freezer spray on the stud itself to thermal shock the thread before removing. I have used this method on car engines in the past where heat cannot be used.

Regards,

David

Dan any luck at getting the stud out yet?

Stu.

stationary stu wrote:Dan any luck at getting the stud out yet?

Stu.

If he tried the weld a nut on tecnique but whack the welder up and very high amps so the nut and stud is glowing red and leave to cool down 9 times out of 10 it works !

since i discovered it thats what i allways use now .

matt