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Removing Exhaust Nuts
Posted: 08 Apr 2025, 19:19
by joshmc
Hi All,
Currently in the process of removing and refreshing the 1.9 DG in my van. Its out on a bench and getting stripped down slowly. I hoped I could get some advice on what technique to use to remove 4 exhaust nuts that no longer really look like nuts. Its the 4 on the front side (as in towards the cab) of the engine, eg the ones under the thermostat.
I'm a pretty amateur mechanic but have access to basic tools. I've got a MAP torch too which I think will be important.
At the moment my plan is- super heat the nuts as much as I can, hammer on a socket or spanner and try and loosen off. If they snap then attempt to drill them out with a cobalt drill. That said, its new territory for me so wanted to get some advice. What's the best way to proceed in hopes of getting them off un-snapped?
Cheers all!
Re: Removing Exhaust Nuts
Posted: 08 Apr 2025, 19:43
by davidoft1
Heat them , let them cool, wire brush them , wd40’ them , wait a bit , heat, wd40 then see if they will move a tiny amount , is they do turn them back again, more lube, then back n forth and see how they come off
Re: Removing Exhaust Nuts
Posted: 08 Apr 2025, 21:02
by Robsey
I used a Maap gas torch to heat mine.
It worked for most of my studs.
One or two studs still snapped but careful drilling, starting with a small drill bit and working up to size worked for me.
Re: Removing Exhaust Nuts
Posted: 09 Apr 2025, 06:39
by shepster
If the studs are OK, which is doubtful, can you get a 'nut splitter ' on?
Alternatively use a dremel type tool with small cutting disc to slice the nut, If stud replacement is required then the above advice is perfect.
I did some in the past but used some 'repair studs' which were M9 on the one end and M8 on the other, the reason for this was however careful I was removing the old studs the new holes were always that little bit 'loose ' when retapped in M8, the extra 1mm gives a nice tight thread once again.
Re: Removing Exhaust Nuts
Posted: 09 Apr 2025, 08:39
by maxstu
shepster wrote: ↑09 Apr 2025, 06:39
If the studs are OK, which is doubtful, can you get a 'nut splitter ' on?
Alternatively use a dremel type tool with small cutting disc to slice the nut, If stud replacement is required then the above advice is perfect.
I did some in the past but used some 'repair studs' which were M9 on the one end and M8 on the other, the reason for this was however careful I was removing the old studs the new holes were always that little bit 'loose ' when retapped in M8, the extra 1mm gives a nice tight thread once again.
That would be my advice too. Remove the thermostat.
Using a dremel or angle grinder with a cutting disc, cut a slot down the side of nuts. Then split it with a chisel.
If the studs are okay, use a a die set to clean up threads.
Re: Removing Exhaust Nuts
Posted: 09 Apr 2025, 13:26
by Alfredo
Re: Removing Exhaust Nuts
Posted: 10 Apr 2025, 06:50
by silverbullet
If its on the bench, use a slitting disc down the side of the studs. You may have to make two cuts. Or use a powerfile, which is useful for many other things!
Every mechanic should also own a set of Irwin Nutbusters, although if the nut is really badly rusted on then there is the risk of stud breakage. Warm (spit boiling hot, not red hot) and soak with penetrating oil.
Take your time and be gentle, but firm.
Die nuts to clean the threads. If they are really rotten then get the gas going hard on the boss around the stud, then use a stud extractor to remove.
Re: Removing Exhaust Nuts
Posted: 10 Apr 2025, 07:52
by simonmarsh
hello - not sure if you have tried a set of sockets for rounded nuts (no pun or innuendo intended) - I bought a set of 5 or 6 and they do work - mine are Erbauer I believe and were around £20 - could be worth a go in conjunction with the other suggestions if you're struggling to get a socket / spanner on them?
Re: Removing Exhaust Nuts
Posted: 11 Apr 2025, 13:11
by joshmc
Hi Everyone
Thanks a ton for all the awesome responses here! It seems like some combo of all would be best. I am going to spend some time heating them, cooling, and soaking in plus gas while I get the rusted thermostat bolts out.
I'd never considered cutting the nuts for the exhaust away, I guess the theory there is that it allows the exhaust manifold to just slide off the thread which sounds like a good plan. I like that idea so will probably look to get a Dremel and cut them away.
I suppose with this I just have to be very careful not to cut too deep as to damage the stud/exhaust manifold itself?
Thanks for the great advice, feeling like I can figure it out now. Then on to the head studs and getting the heads off
Re: Removing Exhaust Nuts
Posted: 12 Apr 2025, 04:31
by maxstu
joshmc wrote: ↑11 Apr 2025, 13:11
I'd never considered cutting the nuts for the exhaust away,
I suppose with this I just have to be very careful not to cut too deep as to damage the stud/exhaust manifold itself?
[/quote
Si
That's where the use of a very sharp medium sized cold chisel and hammer comes into play.
Cut into the nut about half way to three quarters depth horizontally. Then place the chisel point in cut gap at an angle and tap away anti clockwise. The nut will either break open or start undoing as the cut relieves clamping pressure on the exhaust stud.
A squirt of Plusgas and wire brushing helps too.
Re: Removing Exhaust Nuts
Posted: 12 Apr 2025, 07:19
by Oldiebut goodie
chisel is a bit old skool - use a nut splitter.
Re: Removing Exhaust Nuts
Posted: 12 Apr 2025, 07:28
by maxstu
Use what's in the toolbox. Plus it's (to me) most satisfying watching the nut ping open
Re: Removing Exhaust Nuts
Posted: 12 Apr 2025, 18:21
by silverbullet
Thermostat housing bolts require a LOT of care, the top one is capable of breaking a lump out of the boss on the head as there isn't a lot of metal around it.
Thats what started my first ever wbx rebuild...
Heat the boss, try to get some penetrating oil behind it as the tapping is exposed, say prayers/make sacrifices as appropriate, grit teeth.
Again Nutbusters are your friend for getting hild of the cap head (aka Allen or socket) bolt.
Re: Removing Exhaust Nuts
Posted: 14 Apr 2025, 20:33
by joshmc
I managed the thermostat bolts today. The bottom one the housing had actually cracked around it, a definite source of the constant drip from my van, which meant it was easy to get plus gas in and free that. Top one was fairly firm and rusty so I smashed in a hex bit and got it out that way- thankfully nothing broken.
On to the exhaust studs over easter with an dremel. Fingers crossed! Appreciate all the advice on here tho, so thanks all.
Re: Removing Exhaust Nuts
Posted: 17 Apr 2025, 11:55
by joshmc
So I've had a crack at this. Sheared off the first nut. I cut into it with a dremel and proceeded to wail on it with a chisel with not even a budge. So I took a nut buster to it and broke it off- but it doesnt look like a nut on a stud it looks like a bolt. There is no sign of the stud running through the thread of the nut- its all one piece.
I know they are supposed to have nuts on the end, but any chance people use bolts for this- and then cutting might not be a good idea?
I'm not sure how to upload photos yet but here are some in a G-drive
https://drive.google.com/drive/folders/ ... sp=sharing
If anyone could take a look and let me now if they look like standard nuts or if indeed they might be bolts. If they are bolts I think I will super heat and attack with the nut busters, as opposed to cutting.
Many thanks!