HowTo: Removing a broken bolt.

[takai]

Well seeing as i wrote this up for PF i thought i may as well copy it over:

So in the vein of Babs' hako thread, and Edos camerawork, i put together a little howto on removing a sheared bolt.

Firstly, find a bolt that has sheared off, like this alternator bolt, soak it with penetrene/rp7/wd40.

And pop a nice little punch mark into the center of it.

Then take your drilling tool of choice, in my case a re-cased Bluepoint air drill:

Internals by bluepoint, casing by supercrap.

Drill a hole down the center of the bolt, carefully. I chose a 3mm bit for this task:

I blame edo for the crap photo.

Then source an appropriate torx bit (i buy them up when they are going cheap at bunnings) and hammer it into the bolt.


Take one shifter with a 1/4" socket on the end and slowly and gently wind it out:


Voila, one removed bolt:

Of course there are other ways of getting bolts out, my favourite if that method doesnt work is to put a tack weld between the torx bit and the bolt.
If that doesnt work then ill drill out to 4.5mm and try an ezybreak... ooops ezyout.... and if that doesnt work ill drill out further and retap/helicoil.

[RAAAH23]

kudos for you nice lil guide i wouldnt have thought of using a torx bit i know there a tool specifically designed for it but this looks like it works just as well

[takai]

I always try first with a torx bit, as you need to drill a bigger hole for the EzyOut, which means that you cant go backwards. Always start with the smallest hole you can and work out.

[4age_fun]

That's cool I thought a torx bit would shatter when you tap it in. (there quite hard+brittle), but that's awesome it works. Will definitely give it a shot. +rep

[DrNick]

i like this idea
do you have any tips for the high tensile bolts, i had one which the drill just kept slipping off.

[takai]

i like this idea
do you have any tips for the high tensile bolts, i had one which the drill just kept slipping off.

Better drill bits, that bolt was a 8.8 high tensile, not a mild bolt.

[wagonist]

Nice.

But here's one for you:
bolt snapped off inside threaded exhaust flange.
cut off from the back, sheared off from the front, i've managed to drill it through upto about 4mm, but any larger bits I try just get heated up & won't drill.

[takai]

The bolt in that case has probably been heat hardened as well as work hardened, i would be going a much larger drillbit, quite slowly but with STACKS of torque. Something like a 70s drill press shoudl be able to do it. Oversize it by about 2-3mm to give a wider cutting edge to dissipate the heat. The bigger drillbit will help to stop it burning up.

[assassin10000]

Don't forget, lubrication will help when drilling too (wd40 is fine). It allows the drill to cut without galling or workhardening, because if it gets too hot it just burns up the lube before the metal get's a chance to harden.

Andrew

[wagonist]

2 problems:
1: the exhaust is still on the car & I'd prefer not to remove it if possible (dump pipe too so it's a bastard), therefore can't get a drill press in there
2: I'm trying not to destroy the thread in the flange as it takes specific bolts with springs attached) to allow for the exhaust movement (it's my flex joint)

BTW 8 x 1.25mm thread

[RAAAH23]

As takai said hi torque is where its at.

Speed will only increase friction and thus increase heat rendering the drill bit usless no matter how fast you go. if you dont have a 70's drill press just set your electric drill, (not battery drill) to the lower speed (which will make the highest torque)

Id suggest you go to a local machine shop or maybe even bunnings and see if they have any cutting solvents, while these help the drill bit penetrate the metal they also, depending on which you buy act as a coolant so win win but def go the slower torque option first.

[YLD-16L]

Steve, surely you have a mobile service for exactly this purpose up in Sydney?

We have a bloke here in Canberra who specialises in exactly the probalem you have, busted nuts, studs, bolts, damaged threads etc, he's mobile and does callouts to indivduals and workshops.

Only raising this point as it appears to be beyond your DIY with what you have at hand.

[petergoudie]

I like the 'easybreak' statement as every one I've used broke. However, there is a type that I think is much harder the break and might even work. They have four flat sides and are tapered (no spiral to weaken the design). You hit them in and can wind them in both directions which makes it easier to remove.

In regard to the broken exhaust stud, can you heat it red hot with an oxy torch?

Also, it's posible the thread is an interference fit which means easybreaks might not remove it. One of the exhaust bolts on my 7mge is an interference type and I think it was used so that only one half spun with a spanner on it.

[2jzhilux]

Usually with exhaust studs you will battle to get them out with an easyout .
It is better to drill just under the stud diameter and make sure its centred and then see if you can pick out the remaining pieces of thread and then run a tap through it.

[petergoudie]

If you do get it out think about replacing it with a brass nut & stud. I've had a few cars with brass exhaust nuts as standard. Even if they strip getting them off, they don't strip the steel stud.