S**t

[Guest timswait]

I've just very stupidly overtightened the bottom bolt holding the thermostat housing onto my engine, cracking the housing and shearing the bolt. The housing's not a problem as I've got the one off my 1.6 still, however the remains of the bolt won't shift from the hole. I've used a screw extractor on it and it is damn tight, I snapped the extractor off in the stud, so I now have that to contend with also. I'm not sure that one bolt will hold the housing on completely leak proof, so want a bottom fixing. I thought of drilling it out and tapping a slightly bigger thread, but there's a chassis member in the way so I can't get the drill completely square without raising the engine, and I don't want to hire an engine crane for another day (also the hardened steel screw extractor won't make drilling accurately easy). My other idea was to roughly drill it out and weld a stud in, has anyone got any better ideas?

[Mat-Moo]

Have you got a dremmel type tool? Try creating a groove into it and using an impact driver, or even normal driver. I've found that a dremmel will cut through the hardened tip bits,

[Guest Andy Rathbone]

you could try a helicoil kit to drill hole out bigger tap it and coil it so the original bolt size can be used not sure if will work on the cast iron block, theres no reason why it wont though. good luck it sounds like you need some

[Big Jim]

If you can get a blow lamp to it, get it hot, bloody hot, then try tapping it undone with a centre punch. it's the rust that's holding the original bolt, you need to 'burn' it away.

Good luck!!

[Guest dajimmy]

you may be able to build the stud up with weld very carefuly, then weld a nut to the top. This has the effect of heating and gives you something to get hold of. weather it works depends on your welding and a bit of luck. This works better if the surronding metel is alloy as you cant weld to it. If you try good luck

[Guest Lindsay]

if you can get your hands on a mig welder this is what to do, weld a nut on to the screw extracter and get that out the way. try and drill a hole up the centre of the broken in stud, fill the hole up with weld, let it cool. this has the effect of shrinking the bolt, then weld a nut on to broken in stud, let that cool and hopefully it should screw out.

It does work!!

 

Good luck

 

Lindsay.

[Guest daveg]

Tim

 

Thats the reason I currently own a mig welder

 

Do as Lindsay says, I have done this a number of time because motorbikes

seem to have crosshead screws with the cross made from cheese or butter or something similar

 

Dave

PS Freezer spray from RS or CPC is useful as cooling contracts metal making it easier to turn but that not much use to you...

[Guest Simon cooper]

Do you have anything actualy sticking out or has it snapped off "Flush"?

If you have a little to work with, tap it with a small Tack hammer for about 5 minutes, then grip it as best you can and sharply jolt it anticlock. The tapping releases the corrosion between disimilar metals. If it does not work first time, try the tapping again, it will free in the end.

Simon