Hello Mr. Kato,
If you`ve not got the stem loose yet, humor me and read this when you have time.
In the past few months I`ve had a total of four of these stuck stems or seat posts. Gave up on the first one- sold the Prewar Cycletruck frame as-is, tried everything I knew, soaked it with PB, WD-40 and tried heat- nothing, Even cut the stem off, so I could remove the fork from the frame-to better work on it by putting it in a vice. Finally, gave up and Sold it... Ran across the same problem again,Prewar Dayton Frame - nice fork with stuck stem. It`s hard to say how I came up with this. Again, I soaked it for days with PB- nothing... Didn`t try heat on this one.
Let me back up just a little... I have a 1946 Columbia that I ride. A few months ago, I bought a set of Bare metal repro tanks, rack and chain guard off Ebay. I put them on the bike as-is and have never painted or even primed them. So, every once in a while I take WD and steel wool and quickly knock the rust off. Well, one day I was out of WD. So, I put some regular PINESOL, in a spray bottle and it worked as fast as the WD on removing the rust. So, I used it from then on.
Back to the Dayton Stem--- had soaked it for days... nothing! I had spent about a half hour that day trying to break it loose--wouldn`t budge. Something sparked in my head to try the Pinesol. I don`t know why. I sprayed the stem several times- waited about 15 minutes and "IT BROKE LOOSE !" I don`t know if it is a chemical reaction between the PB Blaster and the Pinesol, or if the Pinesol is simply washing out some of the rust material and dirt that was loosened by the Blaster -or what. But it worked. A few weeks later- a stuck Seat Post in a Schwinn Phantom---wouldn`t budge. Didn`t soak it for days this time- sprayed it with PB, still wouldn`t budge. Waited 15 minutes and sprayed it with Pinesol- had it out within 10 minutes. Might be a FLUKE... maybe, but another guy on the forum had a stuck seatpost in an Aluminum Silver King. I told him about it, but I don`t think he put much belief in it. But he said he tried it. He eventually got the post out- but said it was the combination of everything tried that did it. That is my POINT...
Okay, circumstantial evidence so far. This Week ; another stuck stem in a 1946 Schwinn Girls B6- broken stem bolt " This Junk is KIlling Me --nothing is easy!!!" Again, with the Blaster- sprayed it for a couple of days and let it soak. Wedge had fallen down, but stem wouldn`t budge. Finally had a little time to spend on it-- Tried it first to see if it would break loose--nothing ! Sprayed it with Pinesol, waited - and again had it out of the Bike in a few minutes...
My point is---after you`ve tried everything else, spend two dollars--Humor an Old Man, and let me know if it works... I am three for three, help me with my research...
I wish You Good Luck My Friend, -------God Bless,---Cowboy
I don`t know why it works- I`m not a chemist... And, Your Bike is AWESOME !!!