Original Grease Gun Rebuild
 

After cleaning out years of old grease, this is what I have. What do I need to rebuild it?
The deteriorated layered paper gasket/seal(?) was at the bottom of the barrel. Is that suppose to be there?

Re: Original Grease Gun Rebuild
 

Don't know what the paper wad is, but everything else looks good. put it back together and see iff it will work sans the wad.

Re: Original Grease Gun Rebuild
 

Are rebuild kits available or are we on our own? I have several and one worked pretty well but the plunger finally gave up the ghost.

Re: Original Grease Gun Rebuild
 

I think there is some material that could simulate the plunger material and could be worked into a suitable part. maybe cork or soft plastic.

Re: Original Grease Gun Rebuild
 

I never really understood how the plunger works on these things! The rubber plunger is free to slide on the shaft, so how does it exert any pressure on the grease to force it toward the tip of the gun when you press the handle inward? What's the purpose of the washer on the shaft? Seems like it is to limit the movement of the plunger on the shaft, but it would only come into play while pulling the handle back out of the gun. In my mind, the washer should be on the other side of the plunger. I'm so confused.

Re: Original Grease Gun Rebuild
 

Did that gun work before it was taken apart? Mine is full of grease so maybe someone else knows your answer.

Re: Original Grease Gun Rebuild
 

To answer Will N... the plunger does not act to force the grease into the fitting. The plunger only feeds grease to the small diameter bore at the working end of the gun, the reduced diameter portion on the end of the shaft acts as piston in that cylinder bore to force the grease out at high pressure.

Joe B

Re: Original Grease Gun Rebuild
 

See attached ZERK Patent, which explains operation.

The plunger forces grease past the ball check-valve and into the fitting.

When the plunger is retracted, the ball check-valve seals, and a vacuum is created at the nozzle.

When the plunger clears the barrel, the vacuum that was formed pulls grease back into the chamber, drawing from the grease that is in the barrel, and sucking the cork seal down with it.

The key to a properly operating grease gun is in making certain that the ball check-valve is operating as designed. Be careful what you use to clear out old grease because you don't want to damage that check-valve.

Re: Original Grease Gun Rebuild
 

Thanks Guys! In reading the patent and using it's terminology, I gather the only reason for the rubber piston is to keep the grease on that side of the piston toward the nipple, and that the grease and rubber piston are drawn toward the nipple solely by the vacuum formed when grease is forced out of the gun by the plunger.

Re: Original Grease Gun Rebuild
 

Remove the plunger and fill with grease. Screw back on and it should work. Mine does. Only a little grease at a time comes out. Press the conical end up against the conical zerks and pump. I grease my whole car with mine.