Cleaning Pistons

[sticky_valve]

I took my recently acquired horn to the local repairman to do some minor solder work and thought while it was there get him to free the bottom valve caps (correctly).

When I collected my horn he advised he did not have the correct size tool to complete the job.

I have not yet tried to soak in WD40, I'll start this process tonight. However the repairman also sugested securing a metal hose clamp around the cap and then taping on the screw to free them up.

Has anyone tried this succesfully without causing damage? Can anyone forsee something I or the repaiman has not considered if the process was applied?

I'm hoping the WD40 will do the trick, just thinking ahead if it does not.

[Dan Schultz]

..... The gentle, repeating approach with a little lava soap on the threads eventually freed them up so that they could go all the way down.

Be careful with the 'lava soap approach'. That stuff contains pumice and pumice will imbed in brass... and can cause more trouble than you started with. There are some very good garnet lapping powders that will not imbed in brass and work very well for lapping pistons, slides, and beat-up threads.

[pjv]

I didn't read all the posts (sorry, my valves aren't stuck) so pardon me if I'm repeating someone else, but;

don't use pliers. You can warp the valve casings.

Once they're unstuck they can always stick again. I put a drop of valve oil on the threads (possibly a useless endeavor) and I always loosen up all valve caps (top & bottom) on a regular basis.

Good luck.

[Alex C]

All you need to do is break the corrosion on the threads. You can tap the bottom caps with a leather hammer (NEVER use a metal hammer) quite sharply on the outer edge striking straight "down." Do not strike "in" toward the casing if using force, a miss may dent the casing.

If the bottom of the valves is buried in the tubing, use a wooden dowel rod on the outer edge and strike it with the hammer. You don't have to strike the valve caps in the direction of the turn (but it helps). All you are doing is breaking up corrosion.

If none of that doesn't works (and it always has for me) take it to a repairman.

Lastly, once you are finished with brushes on the casings and valves, clean and grease the threads.