Sheared easy-out

7Oaks · Apr 20, 2013

Hi, I've just bought a great Series 3 - only problem is it's a non-runner. You can see the sad story of the PO here and here.

The short version is that there is a sheared-off bolt extraction bit in one of the three bolts attaching the thermostat housing to the cylinder head. Photo attached.

One solution I've considered is to simply do without the third bolt and simply rely on two bolts and some sort of silicon liquid gasket - or something like that. Would that work?

If not, from what I read on the web it is impossible to drill out high tensile steel and what is needed is to remove the broken bit is Electric discharge machining (EDM). Does anybody know whether there is a machine shop in a reasonable radius of Sevenoaks?

Failing that I guess it would just be a case of fitting a new head?

Any comments and advice greatly appreciated, Justin

Oldseadog · Apr 20, 2013

Heat it and beat it

If you can heat it up to red and then let it cool you should be able to drill it out.

Don't allow the cast to get too hot otherwise you run the possibility of warping it!

If you have oxy-acet, use a number 3 nozzle, and just keep it on the easyout until red, then go and have a couple of coffees!

It has to be at ambient before you drill it out with a good quality drill bit ... and use plenty of cutting fluid!

SpringDon · Apr 20, 2013

Edm is often called spark erosion, you may have better luck searching for that in your area.

samc88 · Apr 20, 2013

I know a bit of a long way away from where you are at the moment but when it comes to refitting the bolts smear copper grease around them so as if you need to replace the thermostat in the future you reduce the likelihood of the bolts shearing. Was working on the same thing today and as the bolts had copper grease on them they came out a treat

Locky1978 · Apr 21, 2013

Depends how much with you want to put into it. But I've used a diamond tile drill before. It's like a tube with a bit of diamond dust stuck on the end. They're about £4 - £5 This has the effect of drilling a hole around the easy out. You have to run it very slow. When you drill the core out you have the option of welding the hole up and re-tapping it, or sticking a heli-coil in there.
I drill armour plate with tile drills and that stuffs hard!!

Dr_evil · Apr 21, 2013

If its not that far down could you just slowly build up some weld on top then weld a nut on and try to get it out that way ?

ronsealdeath · Apr 21, 2013

Is it a 2.25? just pick up a second hand motor, cheap at the mo ( but going up in price)

pressbrake · Apr 21, 2013

Its very easy to do!
1) bolt thermostat housing back on, this is your drilling jig
2) get good quality drill bit same diameter as clearance hole in housing, this is to create a good central dimple for your tapping drill. Its only the very high tensile bolts that are a pest ie 12.9 alloy steel bolts so your carbon steel bolt will be fairly easy with a nice cobalt steel drill bit.
3) build up to tapping size in several attempts to keep hole central though if you have access to a lathe turn a bush with the I/D as the tapping drill size and O/D to match the thermostat housing, this will holdyour tapping drill central and square ish.
I do loads of this sort of stuff for local garages

simple

Oldseadog · Apr 21, 2013

Read it again!

It's a broken bolt extractor not a bolt that has broken off!

7Oaks · Apr 21, 2013

thanks all! Just off to Wickes now to buy a tile drill and try Locky's plan. Will let you know with what success.

Dr_evil · Apr 21, 2013

Was the extractor cobalt ? if it wasn't could try drilling it out with cobalt

barleywine · Apr 21, 2013

You could try a sharp center punch around the edge of the broken easy out. It sometimes works by enlarging the the hole its stuck in and allows you to remove the broken bit.
Why do they call them easy-outs? I always ask for a hard-out from stores at work when I need one, tell the storeman they very rarely come out easy, good luck

Thor1950 · Apr 21, 2013

Dr_evil said:
Was the extractor cobalt ? if it wasn't could try drilling it out with cobalt

have you seen the picture???????????? if you had you wouldn't be saying what you are.

Oldsea Dog has given the best advice yet

Dr_evil · Apr 21, 2013

on phone so cant see pics well

Thor1950 · Apr 21, 2013

Dr_evil said:
on phone so cant see pics well

then look next time you post count whore

7Oaks · Apr 21, 2013

no joy at Wickes or Homebase - neither had the right sort of diamond bit. will order via Amazon and resume efforts next w/e. Thanks for the advice.

Thor1950 · Apr 21, 2013

7Oaks said:
no joy at Wickes or Homebase - neither had the right sort of diamond bit. will order via Amazon and resume efforts next w/e. Thanks for the advice.

You need to do as Oldseadog said. You have to heat that extractor to cheery red hot. Other wise you will be defeated,as all drill bits will walk and you will end up with a big hole

divie · Apr 21, 2013

I have access to a spark erosion machine and can do this for you. I drill or spark out lots of broken studs and yes even easy out extractors and taps.
With every one that comes to me I always say to people leave it for me to do it is quicker and easier if it has not been attempted and got an off centre hole in it hence the advice from pressbrake. to try drilling with the stat housing bolted on. I am in South Staffordshire and the cost of shipping may be to much with return as well so look around for a local place first.

Thor1950 · Apr 21, 2013

divie said:
I have access to a spark erosion machine and can do this for you. I drill or spark out lots of broken studs and yes even easy out extractors and taps.
With every one that comes to me I always say to people leave it for me to do it is quicker and easier if it has not been attempted and got an off centre hole in it hence the advice from pressbrake. to try drilling with the stat housing bolted on. I am in South Staffordshire and the cost of shipping may be to much with return as well so look around for a local place first.

EDM is a modern marvel. saw them back in early 80's sweeeeeeeeeeeet

pressbrake · Apr 21, 2013

Oldseadog said:
Heat it and beat it

If you can heat it up to red and then let it cool you should be able to drill it out.

Don't allow the cast to get too hot otherwise you run the possibility of warping it!

If you have oxy-acet, use a number 3 nozzle, and just keep it on the easyout until red, then go and have a couple of coffees!

It has to be at ambient before you drill it out with a good quality drill bit ... and use plenty of cutting fluid!

Red hot near thin old cast iron a cunning plan :crazy:

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