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[x25xe]

Well, the past two days have seen me under the Omega wrestling with the old exhaust.

I have managed to remove the old system and have pictured the process for a how to on the subject.  Now I am slightly stuck as, in the process of unscrewing the bolts on both exhaust flanges, the bolts have, of course, sheared as can be seen in the picture below:



Question is, how do I get the remains of the bolts out?  I have thought about drilling them out, but bolts are hardened and not easy to drill.  Would a stud extractor or bolt remover work?  I would be grateful for any ideas.

I did think about angle grinding them out which would of course remove the threaded hole on the flange.  If this was replaced with a simple nut and bolt then this would not matter.  However, getting an angle grinder in there could be an issue.  In addition, I am concerned that lots of vibration from a drill or angle grinder would damage the cats.

On a brighter note, I replaced the off side track rod arm yesterday - discounting the fact that the car was already jacked up, the whole process took about ½ hour.  I will do a how to on this a bit later.

I still have the new exhaust to fit and the nearside steering idler.

[JamesV6CDX]

So the manifold end is OK then... it's where the cats join the mid-section?

If it was me, I'd get a beefy drill on the bugger, and replace with some nuts and bolts...

[toller]

They shouldn't be that hard as although they will get hot they'll never get really really hot and they're never rapidly cooled straight after either.  

Usual method for getting out bolts like that at work is use the angle griner to make the surface reasonably flat so there are no nobbly bits to deflect the drill, then use a small drill to make a bit of a pilot hole (only needs to be a couple of mm) then go at it with a big drill and they come straight out.

[hotel21]

I have and have had to use similar to these before with good results.  Sometimes simply drilling in the 'wrong' direction is enough to get the broken bit out without resorting to extractors etc.

HtH

B

[x25xe]

Thanks for all your replies:

James, yes it is where the mid section joins the cats.

Toller, these bolts are stuck rock solid.  I think that the exhaust system is the original item.  They are well and truly corroded in place.

Hotel 21, I have seen these bolt extractors during a quick internet search for "stud extractor".

I will try drilling using the method suggested and report back.  I will also investigate the bolt extractors.

Thanks again

[Marks DTM Calib]

Angle grind both sides of the broken bolt flat and then drill them.....often they simply wind out when the drill gets a few mm in...

dont worry about vibration......cats arnt that fragile or they would fall to bits on most roads!

[Tony H]

As has been said drilling out ideally is the way to go the bolt will be high tensile steel which although hard should be no match for a good quality h.s.s. drill bit . you would have to drill a hole anyway to use a stud extractor and on the downside extractor are very brittle and hard so if you snapped that off in the hole it would be an absolute pig to get out

[JasonH]

If I had to drill mine out again I'd have taken the cats off.

Using a normal electric drill I found it very difficult to drill the bolts out under the car. If you drop the cats off you have all the room you need.

The downsides are the studs in the exhaust manifold could shear and you need a new manifold to downpipe gasket each side.

[x25xe]

Many thanks for the further advice.

Mark, thanks for reassuring me about the cats.  I did think they would have to stand engine / road vibration but was worried about the constant drilling.........  I have not ground the other side of the stud which I will do before attempting again.  I hope that the studs wind out after a few revolutions of the drill!

Tony, I was using a brand new HSS bit - a Bosch no less.  A colleague at work suggested that I use a Titanium Bit instead which will make much quicker progress.  Is this the case?

Jason, I did think about taking the cats off but, as you say, I then run the risk of shearing more studs in a place with less access.  Based on this, i think that I am forced to continue as I am.

From here, I think that I will grind the other side of the bolts and hope for the best.  If this does not work, then I will have to find a garage to get the studs out I suppose.  That will be a shame though, having got so far.

Will keep you all updated.

[ians]

I would recommend the titanium bits too for this job.
Cheers
Ian

[jonny2112]

When I got my new exhaust fitted last week, three of the four bolts sheared off and they all had to be drilled out. You could use a centre punch to create a starting point for the pilot bit, and it's simply a matter of taking your time.
Looking forward to your progress with the idler as that's my next job  

[x25xe]

I will give the titanium bits a go then.

I did start off with a centre punch (you cannot seem to get automatic ones any more) but the drill bit is just not making any progress.  I reckon that it will be about ½ hour per bolt!!

Unfortunately, progress will be slowed down somewhat as I now have to go away this weekend.  

Will keep you posted on the progress with the exhaust and idler