Badly rusted studs

[photoman]

What is your take on removing badly rusted exhaust nuts and studs.

The two exhaust ports on my BMW 1100RS have the exhaust down pipes retained by 3 x 6mm studs. One side is so bad the nut has all but corroded away. All I can think of is cutting off what is remaining then drilling out what there is left and re-tapping the holes, Then replacing the studs with stainless. (not perfect but at least it will delay any further rusting).

Any other suggestions?

[ThatDippyTwat]

Plus-Gas (other penetrating oils are available) and heat cycle it. Repeatedly. Ideally apply the Plus-Gas after a ride when it's cooled just enough to not evaporate it on contact.
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'98 VFR800 (touring) - '12 VFR800 Crosrunner (Commuting) - '01 KDX220 (Big Green Antisocial Machine)

[photoman]

[WD Forte]

I'm currently doing a lot of corroded and rusty nut/stud work with mixed results.

I did buy an Erbauer nut remover from Screwfix to remove a corroded
exhaust nut and to be fair it gripped well and remove the nut.
Unfortunately the nut was so rusted on it sheared the stud off
a PITA, but that happens sometimes.
Welding a nut on the remaining stud was a bust too as it sheared of flush with the head on the next attempt
Bollerx!
In the end I had to drill it out and helicoil it.

As above, I'd start with Plus Gas/ACF50 etc you might be lucky
other wise you might have to go down the route I did

Here's the nut whipper outer thingy
https://www.screwfix.com/p/erbauer-bolt-nut-remover-set-6-pcs/6083d

Incidentally, I never fit new exhaust studs mega tight
just lashings and lashings of copperslip and nip them up
I'd rather screw a new stud in than go through all the arseache above
Incidentally 2:
Stainless and ally will be more subject to volcanic corruption*
than carbon steel and and ally but I find copperslip helps alleviate this

* some scientific mumbo jumbo
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bikers smell of wee

[photoman]

[Hong Kong Phooey]

If you fit stainless studs, they will work harden and transform into super strength drill breakers. So if you do then just hope none of them break.

My understanding is mild steel was the choice as a sacrificial part of the whole fixture. It's meant to be the weakest link in the chain for a reason, and in the environment of constant heat cycles, vibration and moisture they stand up quite well considering.
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'81 CG125, '97 FZS600 : '99 CBR600F4, '09 KTM RC8

[droog]

I had to deal with a snapped and seized exhaust stud when I was removing the header pipes off my old Hiornet.

I'll recount my experience as it might be of some use to you in getting your exhaust stud out.

I tried using a stud extractor tool but it didn't grip the stud sufficiently to get it turning, after numerous attempts the extractor tool just slipped around the stud when applying serious leverage. I have had success with these extractor tools on other seized bolts but not in this case.

Luckily there was enough of the snapped stud left poking out of the engine block for me to cut a notch in the end with a metal hacksaw. I then used a combination of Plusgas, an impact driver and hammer (with a screwdiriver bit fitted to the impact driver for the slot I cut into the top of the stud) and a propane/butane torch to heat up the stud.

After squirting the stud with some Plusgas and heating it up with the torch, I hit it a few times with the impact driver and finally got it turning. It came out of the block with no damage to the threads (so luckily no need to helicoil the block etc).

I'm just a DIY home mechanic on a learning curve, so naturally I was really pleased with myself and took some pics to commemorate the event (see below).

Stud in the block (this pic was taken after I got it turning - hence the shiny screw threads on the stud)
https://i.ibb.co/bH2VRtF/1.jpg

Engine block, propane torch and impact driver
https://i.ibb.co/ccBKmfy/3.jpg

The extracted stud showing the slot I cut in the top for the impact driver
https://i.ibb.co/Qpx0nYV/2.jpg

[Tdibs]

Well, you have come to terms with the reality that it will most likely snap.

My best results were with giving it a really good wire brushing first to try and get ride of any flakes that will clog up the threads. Heat cycles with a good torch a few times + plus gas. Then attempt to gently work it back and forth, not trying to just get it off in one go. Getting it moving a little, go back, heat, cool then wiggle some more.

Call out welder is a good option to weld nuts on the end if you have exposed stud left. I have done so before and has got 2 studs out for me.

Worst case is removing the head and handing off for machining out the stud.
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Previous : 09 Vanvan 125| 02' Sv650s || Current: 1999 Xj600n | 1992 DR650 RSE | 2005 Fazer 1000

[WD Forte]

It occurs to me that the only reason folk struggle with exhaust fittings is plain old neglect.
If people whipped em orf and copperslipped new nuts on very two years or at least checked the feckers we'd not have the arseache of
struggling with seized nuts and snapped studs so often.

I've never had to fix them on a bike I owned after servicing it , but done a shit ton on other peoples or new to me bikes.
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bikers smell of wee

[photoman]

[droog]

[droog]

If you are going to attempt to work it out by hand a good tip (in addition to using Plusgas, heat etc) is to give the stud some taps on the end with a centre punch and a hammer - the shock waves can help to break up whatever crud is seizing the threads and helps to work the penetrating oil further into the threads where it can do it's job.

Doing this has definitely helped me to free up seized bolts, studs etc in the past without having to resort to more elaborate methods.

[photoman]

I have given this a bit of thought. The exhausts are held on by 3 x 6mm studs either side which in two cases, one of which on either side, are partially hidden by the sharp bends of the pipes which does not help matters. It certainly precludes me from giving all the studs a clout with a hammer

I am now considering using a dremel with a cutting disc to at least partially split the nuts and then remove them but leave the studs intact. The pipes can then be removed so I can get at them without any obstruction in the way. This will leave a reasonable length of stud to work on.

Soaking the studs with plus-gas will certainly help and using a bit of heat and as has been suggested tap the studs with a hammer will also help, then use a good pair of mole-grips to gently try to break the grip in the alloy head. But in what order do I use the plus-gas heat and the tap with a hammer?

[Easy-X]

I'd be curious as to the physics chemistry occurring in the classic stuck bolt (or stud in this case.) In this specific scenario it's steel stud versus alloy head...

Is it the rust creeping down the thread of the stud or alloy corrosion having the biggest impact? Why use steel nuts on steel studs? Surely a recipe for disaster given on most bikes these fixings are exposed to water/dirt/salt spray
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[droog]

[droog]

[Easy-X]

That's one vote for alloy corrosion If copper slip on the threads (or will any old grease do?) is so helpful how come it's not done on every bike from the factory?! It's not a torque imperative area as compared to say head bolts
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[droog]

[xX-Alex-Xx]

[photoman]

[Tdibs]

[photoman]

[WD Forte]

[droog]

[WD Forte]

One tip I found and tend to use on my bikes is
when fitting exhaust studs,as well as copperslip, just run them in
so the amount of thread is equal or 50% more than diameter of the stud then nip them up a wee bit
thassall
I'd prefer having a stud come out with a nut over struggling
with seized nuts/bolts snapped studs etc any day.
When, if occasionally it has happened, I just felt relief I'd got the fecker off more than annoyance
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bikers smell of wee