Dumb question about zerk fittings

[psdx]

This is probably a dumb question, but I've never run across this before - guessing someone on here already has...

I'm greasing all the moving parts on my Kubota mower and one of the zerk fittings doesn't want to accept grease. So I replace the zerk nipple thinking it must have been due to a plugged up fitting. Unfortunately the new grease fitting does not fix the problem and it still doesn't want to accept grease.

When using a pneumatic grease gun - it just stalls and does nothing. When using a manual grease gun, I can operate it with difficulty, but after 100 or so pumps there's nothing coming out anywhere so it appears that the grease is not flowing in.

It shouldn't be this hard but I've never run across this before. As a hint, the dealer would have had this joint apart during a service visit - if that matters at all. The only possible thing I can think to do is shorten the threaded portion of the fitting, thinking possibly it's too close to the bushing inside.

Any thoughts, ideas or suggestion would be appreciated. Thanks!

 

[rjkobbeman]

To test the zerk, remove it and stick it in the grease gun. If grease comes out (which it should... easily) you know the zerk is OK.

Sounds like there is an obstruction in the cavity that the zerk goes into... since you tried two zerk fittings.

Whether the zerk is too long and is bottoming out or if the threaded hole is plugged, you'll have to check that.

When you say the dealer had this joint apart... that is concerning. What kind of fitting/joint are we talking about?

 

[psdx]

The fitting lubricates the kingpin for the front axle on a Kubota mower. I am now questioning if this was ever lubricated properly since the nut that adjusts play in this bushing has needed to be adjusted twice in 100 hours...

 

[kennyd]

Often times there is "pressure" on the joint that you are trying to grease and it stops the flow into the joint. Example: my front axle pivot will not accept grease if the weight of the machine is on it...if I lift the wheels off the ground with the FEL, grease goes right in. Some backhoe joints are like that also...see if you can reposition whatever you are trying to grease.

Edit: I see you added what you are trying to grease...try getting the weight off of that axle.

 

[rjkobbeman]

I wonder if the zerk hole was forgotten during the machining process... and it is a dead-end hole? If it is, you can probably fix it by drilling the hole out (with a bit smaller than the threads of course), but you will have to disassemble the king pin.

Sounds like you will have to do some more investigation.

I would try kennyd's suggestion too.

 

[psdx]

Edit: I see you added what you are trying to grease...try getting the weight off of that axle.

Excellent suggestion - I will try that. BTW - after a few more sweaty minutes with the grease gun, some fresh grease finally came out through the slots in the nut that goes over the kingpin (small amount and nothing from where I would normally expect it). My thought from that is that a very little grease is getting in there, which to me is a further indication that your suggestion is a good idea. More to follow.

 

[rjkobbeman]

Excellent suggestion - I will try that. BTW - after a few more sweaty minutes with the grease gun, some fresh grease finally came out through the slots in the nut that goes over the kingpin (small amount and nothing from where I would normally expect it). My thought from that is that a very little grease is getting in there, which to me is a further indication that your suggestion is a good idea. More to follow.

Sounds like another example of me over thinking a problem... and common sense prevails! I never thought about weight blocking the grease, but does sounds "logical".

 

[CharlieS]

Weight blockage is logical, and a somewhat common issue on equipment. Another possibility too, I've seen grease dry and harden in zerk ports, preventing proper lubricant flow. If getting the weight off doesnt help, try scraping inside the port with a small screwdriver and see what kind if any crud comes out.

 

[Soundguy]

ditto what kenny said.

I have some loader joints that you must unweight or rotate to get grease in.

soundguy

 

[defed]

i've had them where there was so much old, hardened crap in the joint, that it won't take grease. had to take it apart, clean it out, then new grease went right in.