Thanks for the advice. I would have to cut the stud off flush with the hole, and use a right angle drill attachment as access is terrible, but it might be my only hope!

As a last resort you could consider Spark Erosion - this is what a workshop here would do if nothing else worked.
Actually this is a last resort for extracting head studs, but hopefully you wont have to end up doing that too!!
There are a lot of mobile spark erosion services here, sort of 'one man bands' so ask around you may be able to find a friend of a friend who could do it for mates rates?

As an example, here is a UK site I found on Google which explains:

Spark erosion or Spark eroding or electro disintegration on site mobile service

"Spark erosion can be carried out in house, or at your site, anywhere, subject to call out charge, and is perfect for removing broken taps, broken drills and broken extractors, as well as broken bolts and studs."

Have you tried any heat?

If the stud has been soaking in penetrant for a couple of days, try giving the stud a couple of good hits with a two pound hammer to break it loose. Then wash out all the flammables with carb cleaner and then dry with air. Once dry, use a heat source like a MEPS torch or a small oxygen-acetylene flame to heat the stud up while hitting the stud.

By the way, have you attempted to pry the tranny away from the engine?

So I have now devised a plan to remove my gearbox, and it involves cutting. I have now removed the engine oil cooler and can see the rear end of the offending stud, which is not actually in a blind hole, but in a fully tapped hole. In the next picture, the red arrow shows the nut end and the black arrow shows the engine end behind the (removed) oil cooler.

http://forums.pelicanparts.com/uploa...1370808877.jpg


My plan is to cut a slot, removing material from the bell housing only, across the interface between the engine and bellhousing, to a depth required to cut the stud into two. See red line arrowed on the next picture.

http://forums.pelicanparts.com/uploa...1370809088.jpg

This will allow me to remove the gearbox from the engine. It should then be a simple task to remove the remaining pieces of studs from the engine case and bell housing as there will be no access issues.

I will bond a washer to the bell housing to make up the material removed from sawing to allow proper clamp-up on reassembly.

I cannot think why this will not work. If anyone knows differently please let me know!

Hi,

Sorry I do not understand. You have the nut off the stud right? The transmission housing should be a clearance hole. Are you sure there isn't something else that is holding the transmission back?

Paul

Do not do it. Bad idea.

x1,000,000

Acetylene torch and a hammer.

None of the above ideas have worked. The stud is corroded into the hole and will not budge. I have tried heat, penetrating oil, shaking it about, and everything else I can think of. It will not come apart and I need it apart! The gearbox is completely free from the other studs and dowels apart from this one. It has been under the car for 36 years so a with steel stud in an unprotected aluminium hole it is not difficult to imagine corrosion setting in!

Just out of interest to Lapkritis, why is this a bad idea, you don't say? I agree is is not the ideal solution but I can't see why it will not work. All I will be left with is a slight gap about two inches long between the bell housing and the engine casing which I can fill with a bonded shim to allow clamp up. This isn't a sealing surface so this repair will work fine.

Braze a nut on the stud and unscrew the stud from the engine with an air impact hammer.

Paul

It'll come out without hacking the transmission bell housing. Would look like crap and show lack of patience and knowledge of proper techniques for extraction if you hacked it out. You have plenty of material to work with in the photos. If it won't come out for you take it to a pro.

Should also say when encountering corrosion weld wheels or engine/trans you can use a wooden wedge to split. Normally helps to employ a second set of hands to hold things square while driving the wedge.

You did follow Bruce' instruction, correct?

All clutch operating levers and mechanism are removed.

I'm guessing that a lot of advice is coming from people who are not familiar with the area and it's associated strength? The area of corrosion on the stud, considering it's length and diameter, is likely to require more force to shear it out (Pure shear as there is no peeling or torsion loading possible in this case) than the load required to break the engine casing itself, which if the two side were wedged apart would be a thin web in pure bending and would definitely crack under this type of loading.

There is no access for an air impact wrench, and I suspect even a brazed on nut would come off. Brazing is only a form of soldering after all (gluing rather than melting parent metal) and is not strong.

The end of the stud which is protruding is gradually breaking up because I have tried stud extractors and vice grips which just slip and damage the end. Even if I was to weld a nut on, I suspect the protruding end of the stud would shear off at the first thread (weakest point)

I don't intend heating an aluminium casing with an oxyacetylene torch.

Unless you knew it was there, it is unlikely that once I have finished, you would be able to tell it had been done, and it certainly won't "look like crap" and for the information of Lapkritis, I have resored more that a few cars in the past and this is the sort of work around that is often needed to get around difficult situations. If I took it to a pro, what do you think they would do that can't be done at home...please enlighten me?

You don't drive in a wedge willy nilly obviously. You would come in from the bottom where there is meat. You would be extremely hard pressed to destroy the case with a proper wooden wedge and handling.

If you're hell-bent on chopping away and not considering the advice of brazing nuts on, soaking in penetrant etc then you're just wasting time here. I would personally be digging at the corrosion with a pic tool, penetrant, air, heat and wedge pressure until it was free. 30 seconds with a cutoff wheel will also do the job for sure just not anything I would ever consider under any circumstance. Ever.

Yes, but I'm more than certain you have to rotate the shaft that the lever was on to disengage the arm/fork that is around the clutch throw out bearing before the gearbox can be removed from the engine. And that shaft is right there at that corner where things are stuck. Look through the casting "hole" on the top of the gearbox/bell housing and see if the fork is still on the throw out bearing.

Hi Lapkritis, I appreciate your comments, but you still haven't told me why this is a bad idea! In fairness this is a last resort. I have been heating, soaking rattling etc all week and it is having no effect at all. If I thought there was another way, I would go for it but I really don't think this is ever going to let go. The trouble with wedges is that you can only come in from the top and this puts the stud in bending not tension., If I could get a wedge in the bottom it might have been worth a go but there is nowhere to push one in as the casings are hard together.4


Anyway, I have just come in from my garage having separated the engine and gearbox.

The slot was made with a Dremel tool and doesn't penetrate the casing as you can see from the pictures below:

http://forums.pelicanparts.com/uploa...1370896026.jpg

http://forums.pelicanparts.com/uploa...1370896057.jpg

http://forums.pelicanparts.com/uploa...1370896092.jpg

http://forums.pelicanparts.com/uploa...1370896146.jpg

I still have to get the remaining parts of the stud out of course which I am not expecting to be easy. I tried drifting the part in the bell housing out and it really will not budge. I will have to drill it I expect, but at least I have got good access now.

As for the slot, I will fettle this to be perfectly parallel, bond in an aluminium packer and trim to match the outer casing shape. It will be invisible and structurally functional.

When you were applying heat, were you applying to the bolt or the bell housing? I would have gone cherry on the stud and driven a wedge simultaneously. If that did not free it I would allow it to cool fully and then heat the bell housing around the stud while continuing with the wedge. The helper would hold things square to prevent English on the stud. That would probably do the trick with some tugging and 4-letter words. I find "C U Next Tuesday" works as well as any penetrant.

You would have to be very careful as cherry red steel is around 1200 - 1400 deg.F and cast aluminium melts at around 1200 deg.F . Admittedly, the heat sink effect of the surrounding material should keep the casting way below that, but still it could become expensive!