Freeing seized exhaust

[Rougespear]

Hey all, I'm trying to free up (so I can changed it out) the muffler on my mill engine... she's seized good to the exhaust manifold!  I can't fit a pipe wrench on the thread so am stuck using vice grips.  I'm scared to beat on it too much lest I break the cast iron exhaust manifold.  Any tips to removing it??  WD-40 was a no-go!  Unfortunately I cannot source Blue Creeper locally...



Thanks!

[JB Griffin]

Why do you want to remove it? The manifold and muffler can be removed as 1 unit.  Otherwise PB Blaster is miles ahead of WD-40 I don't use WD except for what is was designed for Water Displacement and it took 40 try to get it right. I hear good things about Deep Creep too, never tried Blue Creeper.  If all else fails heat works wonders, heat then apply penetrant while still pretty warm there should be smoke but no flame, usually works to loosen up most anything.

[VictorH]

Is the muffler simply jammed into the exhaust manifold?  If so I would cut the muffler off where is begins to widen with a sawzall or such.  Then grab the lip that's left with vicegrips (one jaw on the inside and one on the outside of the pipe that's left) and give it a firm twist.  It should cave the pipe inwards and free it up.  remember to vacume out the manifold of the grit from cutting and rust that  breaks loose.  I hope that's a clear explanation of my idea.

[Rougespear]

I'm removing it because the muffler presently fails the job of being a muffler: it is loud!  What about running the engine to get the manifold hot and then trying Deep Creep or similar... is that enough heat?

Victor, muffler is threaded into the manifold.  I would like to save the thread nipple as I'm having a tough time sourcing another similar size.

[jwilly3879]

Get it hot and dump some water on it. The quick temperature change will sometimes break the rust loose.

[dean herring]

If you can get some Aerokroil ,spray on, let sit a while , tap on it with small hammer.
At work we call it "The Creeper" its the best I have ever used.
Let us know

[albirk]

Be careful with dumping water on hot cast iron I have cut a pipe off and then slice down across the threads with a hacksaw blade then take your visecrips to roll it out of the threads (maybe tap on the pipe with a hammer and chiesle)

[North River Energy]

Is that muffler threaded onto a nipple, threaded into the manifold?

If so, cut away the muffler above the rolled seam, then make a vertical slice into the remaining section with a thin abrasive wheel. Won't matter much if you cut into the threads slightly.

[Pine Ridge]

Brake fluid works good to free up seized threads.

[coalsmok]

I have had luck getting exactly one of those nipples out of the manifold. Found it easier to change the manifold.
What size is the thread?  Most I have seen are 2 1/2" pipe. Kind of an odd duck these days, but is available from oil field suppliers.  One of the overhaul crew found one at a hose shop in the form of a large hose barb.

[snowstorm]

if the pipe is ok cut close to the muffler and weld a new nipple or whatever fitting you need

[Rougespear]

Snowstorm... I'm thinking you nailed it.  There looks to be enough material on the nipple into the manifold to MIG a new fitting to.  I am trying the brake fluid penetrating oil, and will a couple more days, but so far its not budging.  If after a couple days, I'll remove the manifold, source a new muffler with fittings, cut off the muffler at the base, and weld on a new one.

[Ford_man]

If you are going to take the manifold off the engine and cut the pipe off then with a stick welder go inside the muffler pipe and weld a bead from inside out maybe 2 different places let it cool it will srink and screw out. I HOPE.

[sandhills]

I would agree with Ford man myself, right down to the "I HOPE" part.  That's what I'd do (try).