Which spanner and technique

TonyS

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to remove a VP 2030 exhaust elbow. Unfortunately it has been on for 16 years and seems solidly attached. The spanner size is not clear but 12mm is only slightly loose. A 1/2" and 3/8" 12 mm socket is too big to sit on square. I have tried to remove the first nut with a 12mm ring but it is showing signs of damaging the nut. What tools and techniques do the experts use? I have sprayed the area with WD40.
 

Major_Clanger

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Have you tried an 11mm spanner?

Anyway, apply some heat use correct socket (preferably hexagonal not dodecagonal) with a small breaker bar. Start by turning slightly clock-wise to 'crack' the nut, then it should undo fine if you're gentle. If all else fails then is there room to cut one side of the nut away or use a splitter? Use a proper penetrating fluid, WD won't help at all.
 
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lw395

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Ring spanners are normally bi-hex, i.e. 12 points.
I would use a single hex socket.
I have a few sockets which I've ground down to lose the taper, so they drive on the whole of the nut, not just the top corners. Only really needed for thin nuts.
If you've got a slightly undersize imperial socket that you can hammer on, that's an option.

My favourite penetrating oil is 3in1, ordinary boring thin oil, but preferably applied to work that's been heated so the oil smokes. Diesel isn't bad.
WD40 has a lot of volatile stuff in it, so it mostly evaporates. Try squirting on WD then adding some other oil, the thin wd may help the oil penetrate. WD40 is better than nothing.
 

pvb

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Another vote for trying PlusGas. WD40 is basically white spirit with a bit of added mineral oil, and isn't much good as a penetrating oil.
 

ctva

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Also, run the engine (if the repair does not preclude) up to temp to help. Otherwise a blowtorch on the nut surround to a good high temp.

Good luck.
 

TQA

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Use a 6 sided socket designed for use with an impact gun. Ideally one that is slightly undersized and can be hammered on.

Use an impact gun, battery operated ones are available.

As a last resort get a local expert with oxy acetylene cutting equipment to torch off the nuts. He is most likely working at a scrapyard. NB Wet everything down in advance, shield anything vulnerable and have a hose on standby.

The gas axe is a major grief saver.
 

VicS

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My favourite penetrating oil is 3in1, ordinary boring thin oil, but preferably applied to work that's been heated so the oil smokes. Diesel isn't bad.
WD40 has a lot of volatile stuff in it, so it mostly evaporates. Try squirting on WD then adding some other oil, the thin wd may help the oil penetrate. WD40 is better than nothing.

Another vote for trying PlusGas. WD40 is basically white spirit with a bit of added mineral oil, and isn't much good as a penetrating oil.

Hopefully WD40 Specialist Fast Release Penetrant spray is better than the ordinary WD40 multi-use spray ?
https://wd40.co.uk/specialist/fast-release-penetrant/
 
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Balbas

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on reassembly use copper grease on the thread
Dont do this. Heat up copper grease and it goes hard, so it's not ideal for use on exhaust systems. Best to use the correct technique, which is down there v.

Or fit brass nuts.

Use a 6 sided socket designed for use with an impact gun. Ideally one that is slightly undersized and can be hammered on.

Use an impact gun, battery operated ones are available.

As a last resort get a local expert with oxy acetylene cutting equipment to torch off the nuts. He is most likely working at a scrapyard. NB Wet everything down in advance, shield anything vulnerable and have a hose on standby.

The gas axe is a major grief saver.
Yup, impact gun is the answer. But heat will help. Even if you heat it and then let it cool before trying to undo the nut, the expansion may well have freed off the rust.

As for the gas axe, well the pic (shamelessly stolen from elsewhere) sums up my views on using heat!
 

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pcatterall

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have had some success with the Big Hammer Technique! With a well fitting 'spanner' put some hand tension on the spanner and then give the spanner shaft a sharp blow with a lump hammer. Its the shock that seems to crack the siezed nut. Spanner must be a perfect fit.
 

Daydream believer

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Is heat in one area of the cast iron elbow the right thing?
One would expect it to get hot in use, but that is over the whole area, in spite of the water entering from one point, which will be hot anyway
 

rszemeti

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Worst case, warm it to cherry red with a oxy-acetylene and when it cools, it will come off easily, no matter how rusted it was.

They don't call oxy the "blue tipped spanner" for nothing.
 
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