snapped off bolts..

wijcc · 30 Mar 2015 at 12:02

Hi all,

Two of the bolts for the thermostat housing on my ford focus (2001 1.6 petrol) has snapped off; the head part broken off. I have got replacement bolts to replace them. But can anyone give me advice on how I can remove/extract the two broken ones, it is quite a tight and difficult area to work on.. so any advice tips would be greatly appreciated?

Thanks in advance.

InvaderGIR · 30 Mar 2015 at 12:10

You'll want some form of stud extractor set (if there is accessible bolt left), like this: http://www.screwfix.com/p/stud-extractor-set-8-pieces/20084
Or if you sheered it clean off in the part then you'll have to drill out the remainder, using a bit that's slightly smaller than the bolt and drilling centrally. You may have to then retap the thread of the hole too.

Also, heat and/or plusgas (not at the same time, don't want to create a fireball

) for removing bolts that look stubborn in the future.

wijcc · 30 Mar 2015 at 12:15

Thanks... will give it a go

pepsilol · 30 Mar 2015 at 13:26

Is there anything sticking out? Mole grips?

wijcc · 30 Mar 2015 at 14:28

thanks... will see if any of the bolt is sticking out and buy a set of mole grips

Gaygle · 30 Mar 2015 at 14:33

Drilling works great. Just a matter of trying to get the drill into areas of limited space!

wijcc · 30 Mar 2015 at 14:37

the tight and limited space is the problem.. i will have to do it from underneath the car with it jacked up.

snapdragon69 · 30 Mar 2015 at 14:40

There are some mobile engineers who make a living out of doing this and specialise in it. Main dealers etc.. use them. Have a google for one local to you. e.g.
http://www.brokenstudandboltremoval.co.uk
http://www.threaddoctorservicesltd.co.uk

Dogbreath · 31 Mar 2015 at 07:37

If the bolts have sheared due to corrosion, then I wouldn't go anywhere near them with stud extractors. The extractors are quite likely to shear off as well, presenting a much bigger problem; in general they should not be used on seized fasteners, especially the smaller diameter ones.

In general, heat and shock are your friends, a hard blow to the top of the stud can help to break the corrosion that is holding it in. Heat can also help, though if the housing is screwed straight onto the head or block, then you have little chance of putting enough heat in with a blowlamp to make much difference.

One of the most effective methods of removing seized studs is to weld a nut to the remaining part, provided there is enough left. The intense heat helps to free the stud, and the nut gives you something to turn it with. If that fails then carefully drilling out the remaining stud is probably the best option. Done well, you can often remove the stud with little or no damage to the thread. If you do damage the thread, then it can be drilled out to a larger size, a new thread cut and a thread insert (e.g. helicoil) installed.

Iamzod · 31 Mar 2015 at 19:02

I had this problem with a water pump & exhaust manifold. Both studs were in Aluminium, I welded some metal onto the end of the sheared off studs & then used mole grips.