They are normally really tight and also have threadlock/sealant on the threads.
#6
Scrubcadet10
I've used 12 point sockets on really tight square plugs like that.
if you can get a socket that fits snug, think like an impact wrench, get a hammer and hit the handle of the ratchet towards counter clockwise/ loosening.
#7
StarTech
Scrub, I have rounded off those plugs with 12 pt sockets. 8 pt are better but 4 pt are the best for removal. Oh by the way I have twisted a couple completely in two using an impact so you got to be careful with the amount of torque applied.
#8
Hammermechanicman
Some of those plugs take a 3/8" wrench. You can use a 3/8" extension backwards and put a wrench on the square end of the extension.
Try carefully heating one side of the boss with a propane torch. Then quench with cold water. Apply some penetrant spray for a few days. You could drill and tap it and install a smaller plug.. A sump pump is the best idea.
If you get it off, don't tighten it down when putting it back.
All too many people think they have to crank on them as hard as they can. Good snug and let it go.. if by slim chance it drips some oil, then give it another 1/4 rev to snug it some more.
#14
Scrubcadet10
I always put teflon tape on them too
#15
tagpop
To loosen or remove turn counter clockwise.
Access is usually my problem with these plugs.
Use an open end wrench to determine the exact size 7/16, 14mm or whatever.
use a ratchet and extension, maybe a swivel to get direct access.
I have 12 point sockets that work the best for 7/16 square use a 12 point 1/2 inch socket.
No impact wrench please, no hammer.
If you need leverage (I am a weak person) use a extender bar on the ratchet handle.
#16
tagpop
There is one other trick for tight bolts. Turn it clockwise just a LItttttle maybe 1/100 of a turn then try to loosen it again. You learn this trick before the days of impact wrenches.
