Thread: Grease gun pressure relief.

I'm posting this here because a grease gun is a hand tool, it relates to the McNaught K29 Flexigun but is probably relevant to other cartridge type pressure guns. These guns operate by having a grease cartridge under pressure from a spring loaded piston to keep the grease up to the hand operated pump. The problem with these guns when they are used very infrequently is the combination of constant spring pressure and daily temperature movements cause them to leak through the seal in the piston and out of the rear of the gun. This leakage is in the form of oil which is squeezed from the grease.
This was not a problem when I was working and using the grease gun weekly or even daily but now that I'm retired the gun can hang on the wall unused for months at a time.
To overcome this problem I made this simple device about ten years ago and to date it works El Perfecto. It is a Pressure Relief Jack (PRJ).
One end of the PRJ is equipped with a slotted base plate which sits over the rear end of the gun and the hook connects to the extended plunger handle. The other end of the PRJ has an aperture through which a threaded rod passes with a nut on the outer end. The inner end of the rod has a short length of chain welded to it that connects to the hook.
Before putting the gun into storage you simply pull the plunger handle out as far as the contents of the cartridge allow and seat the base plate on the rear of the gun. You now attach the hook on the under side of the plunger handle and tighten the nut on the threaded rod to draw the plunger fractionally out of the gun. This takes the pressure off the spring of the piston and solves the problem of the leaking gun.
It's raining for the first time in months so I've got time to annoy the computer.
Cheers,
Geoff.