Zerk fitting mystery...?

[Kenneth]

Howdy,

I got a new one-hand grease gun. It has a flexible hose and an end to pump grease into a Zerk fitting.

So far, so good...

Yesterday, I used the thing to grease the loader for my Kubota tractor and I had an odd problem:

I would fit the grease gun onto the Zerk fitting with no problem, pump some grease with no problem, and then could not release the gun from the fitting...

It had an odd "all or nothing" quality. For a while, the gun would remain firmly attached to the fitting, then, it would seem to release. Once released, it would slip off the Zerk easily, but, before that point, I simply could not remove it.

What might be going on here?

Thanks for any help,

[oldswab]

[myford100]

You were probably pumping against some resistance. Is the very front of the schnozzle that fits over the zerk separate such that you could unscrew it a; little? It's possible that it's just a little too tight and when there is pressure it's holding on to keep the grease from squirting out. Try unscrewing it a half turn before you put it on the zerk.

Good luck!

[Kenneth]

Howdy,

I appreciate your comments, but, it is not an issue of the fit of the nozzle to the Zerk.

I say that because the nozzle slips on just as it should, and then, after I pump, the nozzle becomes very firmly fixed on the fitting. Eventually, the nozzle loosens on its own.

Weird...

[Kenneth]

Howdy,

You may be on to something...

The grease did pump properly, I could see it flow out of the joint as it should. But the machinery I was trying to lube was very cold. I will check to see if the nozzle has any adjustment.

This situation is a little hard for me to describe, but as I tried to remove the nozzle from the Zerk, it did not act as if the nozzle were too tight. It acted as if the nozzle were somehow locked on to the Zerk. Then, when it released, it released fully.

It was something like this:

I would apply 40 pounds of pull, and could not remove the nozzle. Then, a minute later, I would apply 3 pounds of pull, and the nozzle would come right off the fitting...

Thanks again,

[Glenn]

I always pulled them of by bending them over at a slight angle maybe 20 - 30 degrees or so instead of pulling straight off. If you'll notice, the lub guys on a lub rack do it that way too. Thinking back, I can't remember ever pulling straight off even as a kid on the farm way back when.

Glenn

[Kenneth]

Hi Glenn,

I had tried that... but until the thing was ready to release, no angle, no pulling, nothing that I could do would make it release. Moments later, a slight tilt, and a gentle pull, and the nozzle came off the fitting...

All the best,

[Batty]

all that is going on is the pressure is building up in the hose of the gun. When you pump the gun the initial pressure locks the hose nozzle to the zerk allowing you to pump one handed if the fitting will not take grease fast enough or is plugged the nozzle will become one with the hose till pressure drops.

[Kenneth]

Very sincere thanks!

I suspect that is exactly the situation. I did not know that the initial pressure would lock the nozzle on.

All the best,

[The Adams Family]

[Bruce Christian]

[Batty]

3000 PSI. Sounds about right, that's why the coupler and zerk lock up while injecting the grease. The pressure drops quickly and lets you pull the fitting off the zerk . But if the zerk is plugged or the joint will not accept grease (or fast enough) the unit locks together. BTW the fittings and hoses are (should be) rated at 6000-7000 PSI

[Kenneth]

Howdy,

I know that guns are rated depending on their configuration. The one that is causing me the problem is a one-hand type and is rated at

5000psi. Another that I have has a level arm and is IIRC rated at 10000psi.

All the best,