Stuck Steering Head Stem Nut -- CB77 1963

[305explr]

I've removed the steering damper and its mechanisms, but the big (34mm?) nut on top of the steering column remains unmovable.

At first I thought it was because of the age/condition of the bike, but in the parts manual it appears to have NO threads! (pg. 58, part #17 -- Honda part # CB727766A)

My understanding is that this HAS to have threads, and it does unscrew, right? Has someone faced a similar situation?

Lots of Blaster and periodic careful hammer taps have done nothing to shake it loose. Because of the aluminum tree, I have not used heat.

Advice appreciated...

[piecutter]

Keep at it. It will come loose. Blaster is a great penetrant, but if you've got some tough oxidation, picture this: try sliding 2 sheets of rough sand paper held tightly against each other. Not too easy, right? Now put oil on them and try it again. Hmmm, not much different. It would take some seriously viscous fluid injected and held at some pretty high pressure to fill in the space between those grains and make it slide. But what if you could make those grains dissolve?
My little secret? Petroleum distillates do nothing to rust, other than make it oily rust. Rust is an oxide of iron created by the effects of oxygen from water moisture bonding with the metal and breaking it down. The oxide does not chemically alter in oil. If you can rinse away the oils with a detergent, an oil free carb cleaner aerosol or even soapy water, you can then free stuck, rusty threaded fasteners simply by softening the rust with the very element that gave rise to it in the first place, water and a little time.
Hydrochloric, sulphuric or oxalic acids which are sometimes used, of course work faster, but they are much harder to control and keep from permanently damaging things you don't want damaged. I've had some amazing results myself with water alone.
Although, I must admit this is one you'll have to be creative on in order to get it wet up under there in the first place. A hose up through the bottom of the stem might work.

Have fun with science!

[ggray]

Piecutter, I have to say that this is the first time I've heard anyone else recommend water to free rusted parts.

A long time a go, in a galaxy far, far away, an old man once told me that the best way to free frozen pistons from a cylinder was to soak the cylinders in water.

He told me water caused the rust in the first place and the best treatment was to add the culprit that caused the initial problem.

I have never tried it but it sounded reasonable.

Up until now for freeing rusted parts, I have used a product called Kriol. It is made by KANO labs in Nashville. They advertise that it will creep into a gap as small as one millionth of an inch.

I used it on my spoke nipples and never stripped one of them.

Thanks for the scientific explanation of the rust process.

Gary

[kustommusic]

305xplr, That nut does have threads,their on the inside of the nut so it can screw onto the steering stem. Did you put any penatrent in the hole left by removing the damper? Have you tried turning the steering head (spanner) nut? Its for bearing adjustment but if it turns just a small bit it might shake loose the stem nut. This has worked for me any way. Good Luck! Kustommusic