Manifold plug stuck

Just remember that HEATING metal causes it to expand so if you are heating just the plug you will want to attempt to remove it after it cools. The Swelling of the plug from heat will hopefully bust the 'grip' the manifold has on the plug. If you heat the manifold around the plug you will expand the metal surrounding it loosing it's grip.

+1 on the wax trick and acetone/ATF mixture.

I'd also use a bonafide breaker bar instead of a ratchet. The handle is longer, no teeth to worry about stripping out and most important MORE LEVERAGE/TORQUE with lesser effort.

Some useless, geewiz info... part of the scheduled maintenance on the 727 wing to fuselage attach lugs/bolts was to remove and replace with new one. After supporting the wing structure with jacks, etc we would remove the old bolt using a "port a power" to push it out. As we were removing the old one a new one was being cold soaked in liquid nitogen to shrink it so it go in with minimal effort. Only reason I mention this is so you will Think just the opposite on heating just the plug.

And it only drips into the bilge anyway...

Pour some acetone/ATF into the manifold and let it soak from the inside.

Just FYI your nomenclature is a little mixed up... You're talking about the "manifolds". The "risers" bolt to the manifolds and are what the exhaust hose attaches to.

Yes, torch the plugs.

Ok guys. Good info. Thanks for responding. I'm going to talk to our maintenance guys at work also about it. They are real good at crap like this too. I'll try to post what I come up with. Tony.

Ok, same problem here a couple of years ago... here is what I did to repair the problem:

Put the riser in a vise so you can hold onto it while turning the plug.

- Use a small drill in each corner of the plug recess.
- drill a few small holes along the perimeter.
- Then drill a large hole in the middle of the plug( as large as you can fit without messing up the sides of the "square"
- knock the rest of the center out of the plug so you can get the breaker bar into it.   
- apply more penetrant (atf/acetone)
- give it a whack with a hammer to loosen any rust.   
- seat the breaker bar really well, (you may need to cut the rest of the outside part off with a hacksaw)
- turn out the plug.

you may only get one shot at this, but it worked well for me.
Good luck!

I use a half inch socket wrench without a socket.

Hers a couple pics. I'll fix and put new plugs in for reference. Tony.

Ok so I pulled the risers. That went really smooth. I'm going to take them into work and see what I can do with them. Should I put a brass or stainless plug back in? That would seem to make more sesnse. What do you guys do? I plan on painting them while they are out also. Tony.