I have a leak in the exhaust pipe just forward of the centre silencer flange so the pipe will have to be dropped to weld it up.

Only potential problem I can see is getting the flange nuts off without snapping the studs. Pretty certain mine have never been off since the car was made. Obviously new nuts needed but should the studs be changed too.

Whats the approved method for removal without potentially creating major league problems. Drilling out snapped studs in-situ, especially upside down, is not on the list of Clives 6 million favourite things to do! Drilling out clean and in line isn't silly hard. Especially if proper drill guide is made first. But it's the principle of the thing. Last exhaust I dropped out it situ had brass nuts on the flange side! Not gonna admit how many years ago, or what vehicle, that was.

If heat is desirable I'm wondering whether one of the affordable induction current heaters is up for such jobs. I know the pro ones work very well indeed but are the £150 (ish) things off amazon et al up for it. £150 to avoid ages struggling and swearing under the car is worth it. £700 to £2,000 for low end of proper jobbies is not.

Really not a fan of waving a gas axe or similar open flame around near the engine bay.

Clive

I've never had a problem with them shearing off, although sometimes the stud unscrews from the manifold rather than the nut coming off the stud. Douse the nut and the end of the stud (at the top of the manifold flange) with Plus Gas first and you shouldn't have a problem. If you want to replace the studs, they are standard M10.

Thanks for the advice from experience. Plus gas dousing starts after I've done the weekly shop so it should be well worked in by time the gaskets, studs and nuts arrive. For the price it's not worth the risk of not having studs if I need them. Got a Coventry die head in the workshop so making studs is trivial but it's more faff than I want to be bothered with halfway through car fixing.

Clive

Got front wheels up on the ramps yesterday and out under this afternoon as the drive was finally dry to start removal.

Score so far is 6 manifold flange nuts well mullered. All were seriously rusted and well undersize on the hex. So lopsided that the Iwin gripper extractor things didn't work. First time they have failed me. Worst thing about the Irwin devices is that if the fail you have usually only got a round bit left.

Managed to get one off by hammering a socket on.

Looks like tomorrow is going to be a looong day! May end up welding nuts onto what remains. Urgh.

Separating the joint to the centre section 80% sheared the pipe. Do I weld up or buy new that is the question. Who makes good one for a year 2000 V8?

Clive

Any chance of getting a nut splitter in there? One of these https://www.machinemart.co.uk/p/cht246-nut-splitter-set/. I've found that once it starts biting into the nut it expands it so you can usually tap it with a hammer and unscrew the nut.

For the joint to the centre section, I just get the angle grinder with a cutting blade out and just cut through the bolts. Sometimes the bolt heads are welded to the flange, but the grinder soon sorts that so you can use standard bolts.

Pretty sure there isn't room for a nut splitter. Certainly not for mine. Probably not the best idea even if one would go in. The original nuts are hard, high tensile, plane nuts. An excellent chance that the splitter base will ride up along the flange so only the hex bit gets split whilst the tip of the blade digs into the thread on the stud. So it will still be pretty jammed.

I'm annoyed with myself for getting overconfident and not engaging the "old car" brain before diving in. So used to pretty much everything that was factory assembled unbuttoning fairly easily. Should have realised that putting the Irwin extractors on lopsided corrosion would have produced an effect equivalent to a rotabroach channeling a wobble broach cutting the nut down to an off centre circle.

Being hard the Eclipse flexible silicon steel blades I keep to put in padsaw handle for confined spaces just bounce off. A fickle doesn't do much either.

Three options for the next step I think:-
1) weld an extractor sleeve with a hex on the remains of the nut using the sticking out bit of the stud as guide.
2) run an 18 or 19 mm rotabroach down the stud to chew off the nut. 18 mm rotabroch is 8 m bore and will take thread off the stud, 19 mm is 11 mm bore so a bit of nut will be left on.
3) make a guide to drill right through the middle of the stud to take a split type extractor and use larger drill to take the stud and thread inside the nut off. Then use the extractor to pull tear remains of the stud.

Make up my mind tomorrow. Getting too old for this crawling around under cars thing

Clive

hi Clive, i have at times used small nails, you cut off the head of the nail and insert them into every second groove in the socket, pointy end out, hold in place with a bit of grease and tap the socket over the nut. the nails are small, 1 mm. also just as a note, cheap impact driver sets are thinner than expensive ones and only have 6 sides so are good on stripped bolts and because they are thin, they fit into the recessed holes at times.

I replaced my catalytic converter section a few weeks ago. Three of the studs snapped leaving a small section sticking out. I attempted the two nut stud removal method on the remains which just fucked up the threads even more.

This tool managed to remove the remains with no effort at all. I was seriously impressed since I didn't expect it to actually work.

https://www.halfords.com/tools/hand-tools/all-hand-tools/laser-impact-stud-extractor-1%2F2in-drive-121932.html

Took a day off for domestic stuff and make space for a fresh look.
jack
The laser tools impact stud remover looks very interesting. I think I know how it works. I wonder if it tolerates out of roundness enough to go over the remains of the nuts. Hafta measure up to see if 12 mm capacity will go over the remains.
mad-as
Nail trick won't work on this as the nuts are too mullered but something to remember.
Thanks
Clive

Nail trick won't work on this as the nuts are too mullered but something to remember.
Thanks
it didn't work because you never tried it, think about what it does.

Got the pipes detached from the manifold this morning before the rain came. Hopefully plain sailing form here once i've gotten the lamda sensor plugs unhitched. No the easiest ones to get at.

Used four 10 mm joining nuts ( ex Screwfix) with about 1/2" worth thread drilled out and similar amount of corner off one end. Slot exposed enough stud to get a good weld on it as well as the remains of the nut. Final score 2 sheared studs and two studs unscrewed. About 2 1/2 hours all told so that trick goes into the book as one to jump to early on in similar situations rather than emulating Jerome K Jerome's riverine adventures and trying a number of things. Which wasted a colossal amount of time.

On reflection I reckon the Irwin extractors aren't the best of ideas on rounded off flange nuts as the tapered top to the flange and the slightly tapered hexagon don't give them much to get hold of.

Managed to break my old style strap on headlamp during all this so I splashed out just under £12 on a modern style slimline one from Screwfix. Distress purchase but I'm impressed. £3 (ish) off list so decent value for money. Old one was a cumbersome PIA with battery box and utility lamp bit all hung off the front so had to be pretty desperate to use. The new stye so much more comfortable.

Clive

Managed to carve out a few hours quality time under the car today and exhaust is finally off. Fractured most of the way round immediately before the joint thingy. Presumably fatigue because the short bit of tube round the joint thing (can't really call it a flange) sits over the pipe proper effectively doubling its thickness to make a stress raiser where it ends.

Fixing plan A is to weld up the fracture then weld a couple of 3 or 4 inch long semi circular sections of pipe to the flange thingie and clamp them outside the pipe to mostly de-stress the weld. In my experience simple butt welds on well used exhaust pipes are always a weak spot. Even if the pipe is still full thickness. Which is why I shopped doing such jobs for other people donkeys years back, however copious the tears.

Total battle to get the cross member out. Had to break out the Irvine nut extractors again and the worked wonderfully well on nuts that hadn't lost shape to corrosion. Replaced pretty much by hand after cleaning up and greasing the bolting faces. Just a few bonks with my big Thoir dead blow hammer to line things up. No doubt that the nylon faced Thor hammers are much better at the shifting lark than the common rubber ended imports. Twice the price and worth it.

Boot over the nearside CV joint appears to be letting oil / grease out. Hopefully just a loose clip. Another job but something I'd not have noticed for a while if it weren't for the exhaust issue.

Clive