Hexagon nuts wont budge...

Hi,

Trying to replace a heat exchanger on an ideal response 120 and the hexagon nuts wont budge a bit. They do unscrew anti clockwise dont they??

any help appreciated.

nige

Reply to
nige
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It's always worth turning a stuck nut clockwise, sometimes helps to free it.

Reply to
Nigel Molesworth

Presumably you've already tried Plusgas. Heat would help, but it might need oxy-acetylene rather than a propane torch. As a last resort cutting them off is preferable to shearing studs.

Reply to
Rob Morley

I like heating to ~120C, then spraying with WD40, if possible. The WD40 then boils, displacing air, and gets sucked in as it cools.

Reply to
Ian Stirling

Propane should give the nut enough heat, but be careful if it is a cast iron boiler. Cast iron likes to be heated uniformly. That's not to say a propane torch will heat up the cast iron that much.

If the threads are corroded, even tightening them before removal may well result in a sheared stud.

You have either to go for the heat, or use a nut splitter, available from your local car accessory shop.

Dave

Reply to
Dave

That method provides a bit of thermal shock which might be useful, although I'm not sure that 120C is enough. I forgot to mention attacking the exposed threads with a wire brush before undoing, and wirebrushing everything and coating with copperease before reassembly.

Reply to
Rob Morley

It's probably not really. This is for 'ordinarily' sticky bolts.

Hitting 170C (IIRC) causes the rust to start to change forms to a less hydrated state, leading to it shrinking, and hopefully freeing up stuff.

Not to mention a bit of light hammering, using a suitable tube to hammer the face of the nut.

Getting to 1700C frees even the stiffest nuts though :)

Reply to
Ian Stirling

Sometimes heating nuts up, even to red hot, doesn't help. If your stud's OK, you could snip your nuts off, and replace with shiny new ones. Try bolt cutters, if you can fit them in.

Reply to
Chris Bacon

Except WD40 is a rather crap penetrating fluid. I find proper penetrating fluid works much better (Plusgas or Halfords own brand)

Loctite now do something that works by freezing and penetrating. Basically just a normal freezer spray (CO2?) and a penetrant combined. On some really stubborn nuts (no I don't mean Dribble) on a turbocharger exhaust manifold it worked really well. It also avoids any possiblility of flareups as is usual when you have naked flames and penetrating fluids.

I don't think it's available through retail outlets just yet though but should be widely available from industrial suppliers - Loctite Freeze and Release 8040 - about GBP5 for 400ml aerosol.

Reply to
Matt

Virtually useless on some things I've tried..

Where can you get Plus Gas?

Reply to
Chris Bacon

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Reply to
Nigel Molesworth

That's because WD40 is NOT a penetrating fluid. It's a water displacer (WD) See

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Reply to
Mark

Thanks for your suggestions, penetrating oil did the trick in the end,

nige

Reply to
nige

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