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Removing 30yr old inlet manifold / carb mounting studs?
Nickp - 11/9/13 at 04:41 PM

I'm looking to do a weber carb conversion on my Dads old Mitsubishi L300. There's an adaptor kit available (or I can make one) CARBURETTOR ADAPTOR KIT 4 STUD 79mm x45mm to 93mm x45mm
Either way I need to get the old studs out of the inlet manifold to fit it. I've locked 2 nuts together and tried one but it won't budge. I'm thinking heat? But dont want to damage the manifold or studs in case I ned to remount the old carb. Anyone had success doing similiar?

Thanks in advance,
Nick

pewe - 11/9/13 at 05:27 PM

There are a number of things I would try:-
Soaking in pentrating oil, or diesel, or paraffin for a few days.
A sharp tap on the top of the stud to jar the thread.
Impact wrench?
Failing that heat is your best friend - unless you're using a thermic lance it's unlikely heat will damage either stud or manififold.
Also a proper stud extractor linky means lots of leverage.
HTH.
Cheers, Pewe10

Nickp - 11/9/13 at 05:51 PM

Ta for the reply.

I'm just concerned they're held in by some Japanese super adhesive that strengthens over the decades

Problem with the stud extractor is it'll wreck the stud and if it still doesn't come out I'm left with a wrecked manifold I can't even bolt the old carb back onto

britishtrident - 11/9/13 at 06:11 PM

With an aluminium alloy inlet manifold a bit of direct heat will work wonders .

owelly - 11/9/13 at 06:20 PM

Are you taking the manifold off or just lifting the carbotooter off?
If it's just the carb and the studs are seized in the ally, try soaking in vinegar, then penetrating oil, then vinegar. Try shocking the nuts with a blunt chisel but obviously don't let stunt dad loose with a 14lb lumper. Then get the heat on!

Nickp - 11/9/13 at 06:39 PM

quote:
Originally posted by owelly
Are you taking the manifold off or just lifting the carbotooter off?
If it's just the carb and the studs are seized in the ally, try soaking in vinegar, then penetrating oil, then vinegar. Try shocking the nuts with a blunt chisel but obviously don't let stunt dad loose with a 14lb lumper. Then get the heat on!


The carb's off mate, manifold's still in place but studs not budging. I don't want to do owt that makes it irreversible, so tw@tting it with large objects is kinda out. Will try vinegar, but it might be 'chip night' tomorrow so may have to go easy

gremlin1234 - 11/9/13 at 09:25 PM

a common trick is to weld a nut on,

but also ensure you try to undo it axially - with a tee bar rather than a wrench or spanner

rick q - 11/9/13 at 11:23 PM

+1 for using a T-bar on it.

I've had success in the past using a 50:50 mix of acetone and ATF [automatic transmission fluid] as a penetrant. It's cheap as chips as well.

That, plus some heat, plus a thump with a hammer should see it done.......

Trollyjack - 12/9/13 at 06:26 AM

heat up just the studs to cherry red then let to cool for 30 mins studs should come out easy then

Nickp - 12/9/13 at 06:58 AM

Ta guys

dhutch - 12/9/13 at 11:31 AM

There is also a lot to be said for (manageable) amount of impact, as said, we're not talking about smashing seven bells out of it, but a good hard short sharp hit. Sort of as hard as you dare without risking doing it any damage with the right weight hammer.


Daniel