robertj298 

Picked up a 1986 Miyata 912 that was in like new shape but I can't seem to get the bar stem loose.
I've sprayed though the bottom with PB Blaster and let it sit but it doesn't want to budge. Any recommendations?

Jeff Wills

Pictures would help.

Did you loosen the center bolt and tap it downward to loosen the wedge? Also, after 30 years it's likely that there is some corrosion between the stem and the fork's steerer. Flipping the bike upside down, filling the inside of the steerer with PB Blaster, and letting it sit a couple days is what I would do.

robertj298 

I did loosen the center bolt and whacked it several times.I turned it upside down and sprayed it and let it soak for 5 or 6 hours .I"ll take your advice and spray more and let it soak for a couple days. Here's a photo of it

dsbrantjr

If corrosion has caused the wedge to stick it will likely take a LOT more that a tap to dislodge it, although it would be prudent to try that first. In either case after a PB Blaster (or better, Kano Kroil) treatment I would suggest removing the wheel and supporting the fork crown with something like a piece of 2x4 securely clamped on its edge to a solid object, with the fork ends off of the floor to avoid damaging them. This will also cause the force not to be dissipated in the tire or flexing of the fork blades. Then, back the stem bolt out a turn or so and hit it HARD with something heavy like a hand sledge to break the wedge loose. You need to generate enough peak force to break the wedge loose, repeated tapping may not reach sufficient levels of force.

due ruote 

Exactly this. You can tell from how the quill bolt head is above the stem that it hasn’t been hit hard enough. The only thing I might add is perhaps a hardwood block between hammer and bolt so you don’t deform the bolt head.

02Giant 

A dead blow hammer would be best.

ramzilla

Take the handlebars, front brake caliper and, front wheel off. Hang the bike from the ceiling over a plastic drip pan. Start basting the head tube with diesel fuel. Wait a day or two. Then, it's Hammer Time!

robertj298 

How far do I have to loosen the center bolt before I whack it?

Gresp15C

I'd say only about a quarter inch. If you can get the wedge to budge by even a fraction of a mm, you've won the battle. You want the bolt to still be threaded into the wedge. You should be able to drive the bolt head all the way back into the stem.

Now, once you've gotten that far, the stem might slide out easily, or it might still be stubborn if there's a lot of corrosion in there, but at least that's another battle.

robertj298 

Thanks guys. I let it soak for 2 days with PB Blaster .Straddled the crown of the fork with a 2X6 and 1 whack with a 4 lb. hammer loosened it right up. Thanks again

Jeff Wills

Like I learned years ago as a skinny lad: if at first you don't succeed, Get A Bigger Hammer.