We in the past with similar type of assembly used a "Port a power"
hydraulic pump.
We removed the pushing piston from the hose end and used the hydraulic pump
end screwed the hose into the threads of the removed grease Zerk.
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_491_491
The idea is to use hydraulic pressure from the port a power to loosen
the old grease .
You may also fill the hose with solvent, Then the "Port a power" will
push the solvent around the pin.
Be very carefull !~
de John KØCQW
Pat Barthelow wrote:
>Folks:
>
>We are stymied in our work to bring the Jamesburg 30 meter dish back into
>operation. The dish is currently in the "stowed" position, pointing
>straight up. It is locked in that position by a 3" diameter stainless steel
>"pin" that is electrically driven up a cylinder, into a hole in the heavy
>steel elevation motion system.
>
>See: http://www.longandflatsociety.com/Default.aspx?tabid=474
>
>The pin's close fitting cylinder-housing has zerk fittings for heavy grease
>liube that probably had not been attended to in years, possibly decades.
>The dish probably had not been the stow position for decades, if ever, as,
>it sat pointed at an Intelsat geosynchronous satellte, low to the horizon,
>over the Pacific since 1968. Two years ago, someone moved the dish to stow
>position. We, wanting to do moonbounce with the dish, have tried the two
>ways to retract the pin to unlock the vertical motion, using the locking pin
>motor drive, and the manual crank, with no luck. We have hand cranked the
>vertical motion support so as to remove any shear forces on the pin; That
>is, the pin is precisely centered in the close fitting hole. The pin is
>so solidly stuck, it may as well have been epoxied into place. Moderately
>powerful forces have been used to try to push the pin down out of the locked
>postion. to no avail.
>Some of us think there may be wear ridges inside the cylinder preventing pin
>movement downward. The pin is in some ways similar to a piston, has a
>connecting rod and wrist pin-like connection in its bottom for motorized
>retractor/inserter drive.
>We are going to investigate that for possible cylinder interference, in
>detail our next visit.
>
>Others think that the 30 year old grease has fossilized to something akin to
>epoxy, or coax seal, and is keeping the pin from moving.
>
>My question is what does thick bearing grease evolve to in, say 30 years, if
>untouched? Stone? Epoxy? Grit?
>
>A parallel to normal towers might be a tower in decades long storage, that
>had heavy greased cable pulleys. Has anyone found 30 year old pulleys to be
>jammed up hard with what used to be lube grease?
>
>73, DX, de Pat AA6EG aa6eg@hotmail.com;
>Skype: Sparky599
>Moon or Bust!--Jamesburg Gang Rides Again!
>
>
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