28 replies to this topic

[Steve Rowe]

Bought a mini yesterday one of the problems i knew about was that one of the bolts on the thermostat was broken off, was giving a 2nd hand head and new gasket set cause he was just gonna swap heads , but i think that's abit extreme ,any ideas on removing the broken bolt i was hoping i mite of got the grips on to it but not enough to get a hold of , drill it out the best idea ? one idea from a mate was to spot weld an old screw to it and see if that does it

[Dan]

The normal method is to cut off the thermostat housing carefully (avoid marking the head surface obviously) and use the remains of it to turn out the bolt. Cut the offending lug off the housing, remove the housing and turn the lug and bolt out with grips as you suggest. This is very common. New housings are about a fiver.

Edited by Dan, 18 September 2006 - 07:16 PM.

[miniboo]

do you mean one of the three studs that hold the housing down?

[Steve Rowe]

do you mean one of the three studs that hold the housing down?

yup one nearest the rad

[miniboo]

and even with the housing off there isnt enough to get the grips on?

u could try welding a nut on to what is left?

eazi outs are an option but i have heard they break quite easily

[Steve Rowe]

and even with the housing off there isnt enough to get the grips on?

u could try welding a nut on to what is left?

eazi outs are an option but i have heard they break quite easily

its broken pretty much flush with the head so cant get the grips onto it sadly ,welding a nut on mite work but knowing my luck id weld it to the head lol

[miniboo]

well if you do then you have a spare head anyway LOL

could try drilling it if you have some decnt drill bits and can get it in the centre

[mini93]

you might have to get a broken bolt extractor ( not sure the real name) will have to drill down the bolt make sure u dont contact the thread...then with a special tool it takes the remainder of the bolt out

[miniboo]

thats an Eazi out.

[Steve Rowe]

if i drill it i can see me having to re-tap it maybe one size bigger

[mini93]

thats an Eazi out.

oh right my mistake

had to use this at college someone mistook the tightening torque wrong and snapped a bolt off into the flywheel..cant say everyone was thrilled

Edited by mini93, 18 September 2006 - 08:29 PM.

[dklawson]

Do not even think of using an EZ-out. If you get to the point where you'd even consider doing such a thing, call around to local machine shops and find out who's got a "sinker EDM". That's the tool used to electrically burn holes in hard materials... and it's frequently used to burn out broken taps and studs.

If anything is left sticking above the surface of the head, use the following method. Heat what's left of the stud with a propane torch. Remove the flame and quench the bolt with paraffin wax (not paraffin kerosene). Strike the head of the stud several times with a hammer as if it were a nail. Repeat the heat, quench, hammer cycle technique at least 4 or 5 times. Then (and only then) put your mole grips on the stud. First try loosening the stud a little, then push it back as if tightening it. Keep this tighten/loosen motion going increasing your movement ever so slightly. Flood the area with penetrating oil and keep working the stud in tighten/loosen arcs as the motion increases. The motion will work the penetrating oil into the threads and allow you to eventually completely remove the broken stud.

[Steve Rowe]

put your mole grips on the stud.

theres not enough to get the grips on to it tho mate

[miniboo]

to be honest it might be easier to change teh head as you have a spare head and then try and get the bolt out at a later date or take it to a machine shop like DK said.

[dklawson]

If the stud is too short to put the mole grips on but is still proud of the top of the head... you could consider sawing or using a Dremel tool to add a screwdriver slot for what is left. Do not plan on using a screwdriver there... use the heat, quench cycles above but replace the hammering with the use of a manual, hammer powered, impact-driver.

That said, a friend of mine used to work at a machine shop. When he worked there, they would charge $30 to remove a broken stud... $50 if the owner had already tried to remove them himself. In short, be smart and careful in your work or it will cost you more.

Again, don't consider an EZ-out. I've posted my feelings about them before but it bears repeating again. Succinctly... you've just broken off the head of a high-strength bolt using the proper tools. To use an EZ-out you drill down the center of that same frozen, broken bolt and pound a small, hard, brittle tool into its core. Somehow, you're supposed to be able to apply sufficient torque to the small, hard, brittle EZ-out to remove a bolt that you couldn't remove when it had its proper head on it. The ludicrousness of this should be obvious. Once you break off an EZ-out your ONLY choices are to mill out the broken tool with a carbide bit/grinder OR take it to a pro and pay to have it removed by EDM.