Hi. I just find out that I have a broken stud in the exhaust manifold, from the previous owner. I plan to buy an extractor and fix it.

Somebody know what are the studs size for a Grande Punto 1.2 8V 2006 model?

do you have any recommendation for the drill extractor size?


I want to get prepared for the big day

stud is m8

Remove the old stud first. If it snaps off, you might have to drill it out and then it might be easier to just put a regular bolt through it, if you lose too much metal to be able to re-tap for a stud. It's M8 though.


Ralf S.

I've removed snapped exhaust studs before.
2 times i had the heads off, once we removed the front bumper and have a lot of space from there.
Good quality drill bits (you will need at least 2, a 4mm one and a 5.5 or 6 mm one)
You have to be very patient, take your time.
Be sure to center the hole 100%
Make sure you drill straight into the bolt.
Drill slow and careful, DO NOT brake the drill bit!

I used some Unior extractors:


As to the size... the biggest that will do the job is the best, less chances of braking it. (DO NOT brake it!!!)
The square end goes really well with a 12 point socket... just make sure you don't brake it, it's easier that one would think.

There's always tapping, or helicoil if it goes wrong.

What is the length of the stud? M8 X

No idea on the exact size, but as i remember.. it should be between 40-50 mm longer is better.. you can cut it, add washers...etc

Use some cutting oil on the drill bit, too. Nasty job, I have a mate i enlist for tasks like this!


Cheers

Thanks guys for the advice's. This will be an interesting project :slayer:

The most difficult part is finding enough space for the drill with the bit.
You need to get comfortable in the awkward position, to be sure you can slowly drill the stud..

aurick86 said:

I've removed snapped exhaust studs before.
2 times i had the heads off, once we removed the front bumper and have a lot of space from there.
Good quality drill bits (you will need at least 2, a 4mm one and a 5.5 or 6 mm one)
You have to be very patient, take your time.
Be sure to center the hole 100%
Make sure you drill straight into the bolt.
Drill slow and careful, DO NOT brake the drill bit!

I used some Unior extractors:

As to the size... the biggest that will do the job is the best, less chances of braking it. (DO NOT brake it!!!)
The square end goes really well with a 12 point socket... just make sure you don't brake it, it's easier that one would think.

There's always tapping, or helicoil if it goes wrong.

Click to expand...

I've had a fair few disasters with screw extractors over the years. Access is often very difficult, then drilling the centre of the bolt and keeping it in line with the axis of the bolt, difficult too. Good chance of breaking the drill when access is restricted and after all that, even if you do get it drilled out nicely, you've still got to get it out with the extractor. Even a good quality screw extractor is quite brittle. It is difficult to "feel" where the point of no return is before it snaps. Cheap quality ones are much more liable to snap and I wouldn't bother with them. Worth remembering that these days you are often dealing with a steel stud in an alloy casing so, if it's a few years old, electrolytic corrosion is likely to be present over the length of the stud. If you snap the extractor (or a drill for that matter) you have my permission to jump up and down violently whilst swearing loudly because now you really do have a problem!

I was shown a method which doesn't use extractors and very seldom fails to work. You do need access to a MIG welder though. The proceedure is:-
1. Take a nut the same size as would fit the stud you are trying to remove.
2. Use a large size drill to chamfer out about 2/3 of the depth of the threaded portion of the nut.
3. Place the nut over the top of the snapped, seized stud. (This works even on studs which have snapped off flush with the hole).
4. Use your MIG on quite a high setting to weld the nut to what's left of the stud. It's very important to make sure the end of the wire melts the stud metal first and then flows out to the nut and fills it up flush with the top. You will not get weld metal adhering to aluminium or cast iron casings. A little more care and precision is needed when working on steel (maybe a suspension arm or the like)
5. Let it cool till it's not glowing bright red any more and give it a good hosing down with a releasing oil of your choice (I like Plus Gas but WD40 or other stuff will probably pro just as well)
6. Unscrew.

I believe the releasing oil helps by thermal shocking the metal and cracking the hold of any corrosion. Because the steel stud is small and often of a different material to the casing it's screwed into the rate of contraction is different and so the releasing oil finds its way in and helps the unscrewing.

There are a couple of things to consider. 1.Chamfering out the nut helps a lot with "aiming" the MIG wire at the end of the stud. 2. If you are used to MIG/MAG welding then you will need to increase your welding temps over what you would instinctively select. The time available to get good penetration on the end of the stud is very limited.

If the nut just twists off the end of the stud without turning it you didn't get penetration on the stud. Don't be too concerned about damaging the casing. As long as you choose a nut which is suitable for that stud size there is little chance of you "burning" the casing metal and anyway you want to put as much heat into that stud as you can. Don't try to undo it too soon. The stud and nut will be soft if too hot. Finally, on the subject of access. I find this method far easier. You can get the MIG torch into places a drill has no hope of going and you can afford to angle it a bit as long as you get that melt on the stud first. The ones I find ussualy won't respond are on exhaust systems where the corrosion is so severe and it's often a steel stud in a steel or cast iron downpipe. In this case, if the rest is serviceable, I would just drill right out and use a nut and bolt or tap out the casting. (Sometimes a visit to the Scrappie is the only solution - occassionally you do reach the point where it's just not worth persevering!)

Need I say though that you need to be VERY CAREFUL of fuel lines, electrical wiring and possible damage to electronic components if you are going to give this a go. If you have a MIG already you are probably aware of all the pitfalls. If you are just going to borrow someone else's or are unfamiliar then take advice or get a mate in the know to help. You can do a great deal of damage with a welder so don't blame me if you burn your car to the ground or ruin an ECU! On the other hand, good luck to you if you decide to give it a go, I haven't wrecked anything yet by doing this. Maybe try it out on an old scrap component before going anywhere near your car if you are unsure.

Hi ddaniel.

Have you had a go at it yet?

I'd be interested to know how you get on

These jobs can be a real dog. Hope it goes well for you.
Regards
Jock.

bought a grande with 3 snapped bolts stuck inside head, nice

Thank you all.
I solved the problem... I sell the car

Then I guess we'll soon have a new post with broken studs issue ;-)

BRs, Bernie

Does the Punto use studs+nuts for the exhaust manifold? Does the size change for other late Punto models or is it the same across most Fiat engines? I have the 1.4L 8v.