thermostat stud!

[mattyguk1]

hi all,one of my thermostat studs has sheared off flush! has anybody had any joy with the "easy out" type of extractors? are these any good even though the studs seized in, if not i guess i will have to carefully drill it out...

[mascher]

A left-hand drill bit is better than a right-hand one for removal. On a head or block you can usually weld a nut on to the studs even when they are broken flush. The weld filler will attach to the steel in the stud long before it will attach to the cast iron head. Some of it's the material difference and some is that the head is much more massive and makes a better heat sink.

Kelley

[chris-pilling]

If you decide to drill it out and use an extractor then make sure you used a centre punch first. if you dont you will find it very hard to drill it straight!

what kelley said is a good idea if your good with a welder, cast iron is very difficult to weld too even at the best of times, improbable when cold! like he said it will attatch to the steel before the iron!

[vulcanbb18]

Sometimes I've been lucky when they snap off flush, and I've been able to tap them out with a punch (tapping in an anti-clockwise direction of course ). It must release the tension on the threads enough to release it... or something!

cheers

Jacob

[coop12g295]

I use a Rigid fluted extractor set which has the correct drills
and also drill centring mandrels. Mark the centre of the stud
centre punch, drill through apply heat wd 40 more heat then
knock the extractor in. Not failed yet but be patient

[chris-pilling]

I use a Rigid fluted extractor set which has the correct drills
and also drill centring mandrels. Mark the centre of the stud
centre punch, drill through apply heat wd 40 more heat then
knock the extractor in. Not failed yet but be patient

are those the Wurth ones? i have a set of them at work and there marvelous!

[mk1]

My preference is to drill it out after centre punching the stud first & then fitting a helicoil.

All the above mentioned methods are cracking it's just a case of horses for courses.

A good whack with an oxy torch will usually free up a sticky stud too.

[Vegard]

I've had good success with drilling holes, and fitting torx-bits. I mean hammering them in. Yes, you may never get the torx bit out again, but that usually works.

[mattyguk1]

thanks chaps, coop12g295 is this similar to the extractors you have ebay item number 400154439071 ? if i drill it out with a reverse/left handed drill bit what size bit would be best?

[mascher]

Use the largest drill possible that is smaller than the threads but it must also be small enough to account for any inaccuracy in centering the drill. Bigger is better since it will have more leverage and be more likely to back out the stud.

Another way to remove steel from cast iron is to use a cutting torch. Heat the stud until it is almost molten and then pull the oxygen lever. The steel will liquefy and be blown out of the hole, the cast iron, even the threads won't be touched. If I remember correctly the high carbon content of the cast iron won't let the cutting torch cut it.

Kelley

PS: I've never convinced anyone to try the cutting torch trick, but it does work, you just have to watch out for splashing molten steel.

[mattyguk1]

thanks all,well the reverse drill be didnt work so im left with a 4mm hole drilled through...do i now try any easy out or drill it all out and re-tapp the hole? if i re-tapp what size tapp will i need and will i need an over size stud?

[Tim]

If you drill the stud out without damaging the threads in the head, you can just fit a new stud, its possible to do but rarely works. If you do damage the threads you then drill the head a little bit bigger, tap it for a thread insert and fit a new stud.

I'd give the ezyout a careful go first, but remember, if you break it off its harder than a drill bit and you'll be really up the creek.

Tim