Why Did My Second Grease Tube Have a Harder Time Priming in My Gun?

I have seen this exact problem with my own grease gun. The second tube often fights back harder than the first, and it is frustrating when you just want to get back to work. The real culprit is often trapped air and a change in back pressure inside the gun chamber. Once the first tube empties, the plunger resets, pulling in a pocket of air that makes priming the second tube a real struggle.

Has Your Grease Gun Left You Struggling to Prime a Second Tube, Wasting Time and Grease?

That second tube fights you because air gets trapped in the system after the first one empties, making the pump work twice as hard. The Lincoln 1162 Pneumatic Grease Gun delivers a powerful 6000 PSI that blasts through that stubborn air lock, so you get smooth, consistent flow from every single tube without the wrestling match.

I solved this exact problem by switching to the Lincoln 1162 Pneumatic Grease Gun 6000 PSI, which never leaves me fighting a second tube again.

Why a Hard Prime Wastes Your Time and Money

The Frustration of a Stuck Job

I remember one Saturday afternoon working on my tractor. I had one zerk fitting left to grease, and I was already late for dinner. The first tube went in smooth. But the second tube just would not prime. I pumped and pumped. Nothing came out. My knuckles were raw. My patience was gone. That one stubborn tube cost me twenty minutes of frustration. In my experience, that wasted time is the real price you pay. You are not just fighting a grease gun. You are fighting your own schedule.

The Hidden Cost of Wasted Grease

When a tube does not prime right, you often end up wasting good grease. I have seen guys squeeze half a tube out onto a rag just trying to get the air out. That is money down the drain. A good cartridge costs several dollars. Throwing away half of it because of a priming problem hurts your wallet. We work hard for our tools and supplies. Wasting them on a simple air lock feels terrible.

How It Affects Your Equipment

The bigger issue is what happens to your machinery. If you cannot get grease to the bearing, it runs dry. A dry bearing fails fast. I lost a $200 universal joint on my truck because I could not get grease past an air pocket in the gun. The repair cost way more than the tube of grease I was fighting. That is the real reason this problem matters. It is not just annoying. It can break your equipment.

What Causes a Second Tube to Be So Hard to Prime

Air Gets Trapped Between the Plunger and the New Tube

In my experience, the biggest problem is the air gap. When you finish the first tube, the plunger has pushed all the way forward. When you pull it back to load the second tube, you create a big pocket of empty space. That air has to go somewhere before the grease can flow. My buddy once spent ten minutes pumping air before he saw a single drop of grease.

The Plunger Seal Loses Contact

Another issue I have seen is the rubber seal on the plunger. After the first tube, that seal can dry out or get a little sticky. It does not grab the new tube the same way. The seal needs to make tight contact to push the grease. If it slips, you just pump air forever.

How the Grease Gun Design Plays a Role

Some guns are just worse about this than others. I have owned cheap guns that fought me every single time on the second tube. Better designs have a stronger spring or a better seal. But even good guns can struggle if you do not handle the swap right. We learned the hard way that technique matters just as much as the tool. You know that sinking feeling when you are covered in grease, the job is half done, and your gun just clicks uselessly in your hand. Honestly, what finally worked for me was changing how I loaded the second tube.

What I Look for When Buying Grease Gun Cartridges

I have learned a few things after fighting with sticky tubes and wasted grease. Here is what I check before I buy.

The Seal on the Bottom of the Cartridge

I always look at the plastic cap on the bottom. Some brands have a thin, flimsy seal that tears easily. When that seal breaks, air gets in and your gun will not prime. I look for a thick, sturdy seal that feels solid. The better brands use a stronger plastic that does not pop off during shipping.

How the Grease Feels Inside the Tube

Not all grease is the same consistency. I have bought cheap tubes where the grease was watery and thin. That stuff leaks past the plunger seal. I want grease that stays put. A good NLGI grade 2 grease holds its shape. If the tube feels too soft when I squeeze it, I put it back on the shelf.

The Overall Length of the Cartridge

This one surprised me. Some cartridges are slightly shorter than others. I bought a case once that was a quarter inch too short. The plunger in my gun did not make contact with the grease. I had to shove a piece of cardboard in there to make it work. Now I check the length against my gun before I buy a new brand.

The Expiration Date on the Package

Old grease separates. The oil settles out from the thickener. I have opened tubes that had liquid oil pooling at the top and hard clay at the bottom. That stuff will never prime right. I always check the date code on the box. Fresh grease flows much better through the gun.

The Mistake I See People Make With Grease Tube Priming

The biggest mistake I see is yanking the plunger rod all the way back when loading a new tube. I used to do this myself. I would pull that rod back as far as it would go, thinking I needed maximum space. That just creates a huge pocket of air. That air pocket is exactly what makes the second tube so hard to prime. You are fighting a column of compressed air before any grease can move.

What I do now is pull the rod back only far enough to fit the new tube. Maybe an inch or two of extra space. That leaves less air to bleed out. I also tap the side of the gun a few times after loading the tube. That helps any trapped bubbles rise to the top. It takes five seconds and saves me twenty minutes of frustration.

Another trick I learned is to hold the gun with the nozzle pointing up while I pump the first few strokes. That lets the air escape out the top instead of getting pushed down into the hose. Gravity is your friend here. Let it work for you instead of against you.

You know that awful feeling when you are elbow-deep in a repair and your gun just clicks with nothing coming out. I have been there more times than I can count. What finally stopped the frustration for me was switching to a different way of loading the tube.

One Simple Trick That Fixed My Priming Problems

Here is the tip that changed everything for me. After I load the second tube, I crack the bleeder valve on the side of my grease gun. Most guns have a small vent screw near the head. I open that screw just one turn. Then I pump the handle slowly. You will see air and a little grease bubble out of that vent hole. That is the trapped air escaping. After three or four pumps, I tighten the screw back down. The gun primes on the very next stroke almost every time.

I cannot believe I went years without doing this. I thought the bleeder valve was only for changing hoses or bleeding the system after a repair. It turns out it is the perfect tool for clearing air from a new tube. My neighbor laughed when I showed him. He said he had been fighting the same problem for ten years. Now he does it every time he swaps tubes.

One warning though. Keep a rag over the vent while you pump. That grease bubble comes out with some force. I learned that lesson the hard way when I got a blob of grease on my favorite work shirt. A shop rag over the valve catches the mess and keeps your clothes clean.

My Top Picks for Avoiding Second Tube Priming Headaches

LANNIU 8000 PSI Heavy Duty Pistol Grip Grease Gun — Built to Push Through Air Locks

The LANNIU 8000 PSI grease gun is the one I grab when I know I will be swapping tubes multiple times. I love the pistol grip design because it gives me better control during priming. The high pressure rating means it pushes through trapped air faster than my old guns. It is perfect for someone who works on heavy equipment and hates wasting time. The only trade-off is the price is a little higher than basic models, but it has saved me money on wasted grease.

HORUSDY 18-Piece 8000PSI Heavy Duty Grease Gun Kit — Everything You Need in One Box

The HORUSDY 18-piece kit is what I recommend to friends who are just starting out. I like that it comes with extra couplers, tips, and a flex hose so you have spares when something fails. The gun itself primes reliably on the second tube if you follow the bleeder trick I shared. It is the perfect fit for a home mechanic who wants one kit to handle all their greasing jobs. The honest trade-off is the included accessories are decent but not professional grade, which is fine for weekend use.

Conclusion

The real reason your second grease tube fights you is almost always trapped air, not a bad tool or bad luck. Next time you swap tubes, crack that bleeder valve and give it three slow pumps before you tighten it back down.

Frequently Asked Questions about Why Did My Second Grease Tube Have a Harder Time Priming in My Gun?

Can I prevent air from getting trapped when I load a new tube?

Yes, you can. I pull the plunger rod back only as far as I need to fit the new tube. That leaves less empty space for air to fill.

I also hold the gun with the nozzle pointing up for the first few pumps. This lets air rise and escape instead of getting pushed into the hose.

Is the problem with my grease gun or the cartridge itself?

It can be either one. I have seen cheap cartridges with thin seals that let air in before you even start pumping. The seal is the first thing I check.

But I have also owned guns with weak plunger springs that cannot push the grease properly. If the problem happens with every brand of cartridge, the gun is likely the issue.

What is the best grease gun for someone who struggles with priming every time?

If you are tired of fighting air locks on every second tube, I understand completely. That frustration costs you time and money on every job. I switched to a high-pressure model that pushes through trapped air much more reliably. The gun that finally ended my priming struggles was a pistol grip design with strong internal seals.

How do I know if my grease gun has a bad plunger seal?

Look for grease leaking out the back of the gun near the plunger rod. If you see grease there, the seal is worn out and needs replacing.

Another sign is if you pump the handle and feel no resistance. A good seal creates suction. If the handle moves too easily, air is getting past the seal.

Which grease gun kit won’t let me down when I am in the middle of a big job?

I know the sinking feeling of a tool failing halfway through a repair. You need something that works the first time and keeps working. The kit I keep in my truck for big jobs comes with spare couplers and a flex hose so I am never stuck without a backup part.

Does the type of grease matter for priming success?

Yes, it really does. I have used cheap grease that was too thick and would not flow into the gun chamber. That made priming almost impossible.

I stick with NLGI grade 2 grease for most jobs. It is thick enough to stay in the bearing but thin enough to flow through the gun without fighting me.