How do you know if a Milwaukee electric grease gun has lost prime or is empty?

[emmett518]

Any practical advice on easily determining if the Milwaukee gun has lost prime, or is actually empty? Is that why Milwaukee offers a clear, see through grease tube to visually see how much grease is left in the gun?

I'm finding it challenging to know if the gun is actually pumping grease into the joint, or is just pumping air, and if it is pumping air, is the cause loss of prime or an empty tube. Opening the reservoir is always a messy PITA.

Thanks

 

[Tinkerer]

Twist the plunger rod until it engages the piston.
If the grease tube is mt the rod and piston will not retract from being all the way in the barrel.

 

[emmett518]

Can you explain further?

 

[Tinkerer]

Yes,
I used hundreds of tubes of grease when I ran a service truck.
I have never seen a Milwaukee grease gun. I have a Dewalt electric.
Your gun has a round black knob on the head to bleed the air out of it.
I believe all grease guns have an oblong hole (slot) in the cartridge piston. The rod has a pin thru the end of it. The opposite end of the handle. The handle can be rotated to either engage the piston or to line up the pin with the slot in the piston to allow it to pass thru.
When the cartridge is empty turn the handle so the pin engages the piston. If there is any grease still in the cartridge, you will be able to pull the rod out until the cross pin hits the piston. That is how to determine how much grease is in the gun.
You can also force air out of new cartridges by engaging the piston and rod, then push on it while trying to pump grease.
In the image below is a typical piston. It has two plates. When the rod pin is in the center of and turned it can then move the piston.
The rod won't just spin between the plates. It will only turn a small amount and then it will turn the piston with it.

 

[emmett518]

Thank you.