mini excavator kubota; replaced bushing with kubota manuf bushing, in the hyd ram end that connects to bucket linkage. before replacing a little loose and it took grease, reused old pin. with new bushing in ram end only one pump of grease gun to fill grooves between the hyd ram side that contacts the new bushing, and groves of the bushing that are on the hyd ram side of the new bushing with grease; then will not accept any more grease. I dissasembled the linkage twice to try to find out what was wrong. with the pin out grease can be pumped eazy into the opening where the pin would be through the new bushing holes (has two holes). With the pin in and all assembled it will take one pump to fill the groves in bushing between ram end and ram contact side of bushing but will not take any more grease. Grease gun is Lincoln high pressure and all I could force it to move pump leveler and at that no grease would go into bushing after the first one which was a EZ pump. Replaced zerk grease fitting with one from another location of machine that accepts grease. I do not have any idea what is going on. Any assistance will be greatly appreciated.
Did your bushing od have a recess around it? Or was it just a hole? If it was a hole and you didn’t line it up with your bushing then you shut off your passage for the grease.
The new bushing is from kubota it has about a 1/4 inch wide circle around it between ram and bushing area.
Is it identical to the bushing you removed ? Pictures would help. What you described, seems to be the grease groove is on the outside of the bushing. Gotta be on the inside so the pin gets the grease.
grooves on both sides of the bushing.
If possible take photos of old and new side by side to compare them. A groove only on the outside of the bushing would still work provided there were drilled holes from outside to inside to carry the grease to the contact area between the pin and the bushing.
Nige there is a grove on the out side and two holes through the bushing and then like an hour glass or criss cross groves on the inside of the bushing, old bushing same as new one.
Since you say the grease does pass the bushing when the pin is out, I would try a manual grease gun. Perhaps the electric gun can't over come, the now closer tolerance between the new bushing and pin.
I haven't yet come across an electric or pneumatic grease gun that can match the pressure of a good Lincoln lever-actuated grease gun.
I do not have a electric grease gun it is a manual grease gun
Maybe try one of these tools for stubborn/clogged fittings. Link below. I've used them before and it works well. It may help get some grease in for the first round. Can load penetrating oil in to clear clogs. Might just be close tolerance and thick grease is the problem. As long as it's installed correctly, then it should take grease after a little use. https://www.ebay.com/itm/Air-Hammer-Zerk-Zapper-Grease-Fitting-Clean-Tool-Buster-Farm-Maintenance-Cleaner/163610034512?51
Have you tried pumping grease while at the same time someone else slowly moves the linkage containing that pin.?
I did that myself moving the bucket a little then greasing it then move a little; repeat. Some grease did go in on one side, still hard to pump and that was with one of the bucket linkage off. So I could turn or rotate the pin with adjustable plyiers.
I had a boom to stick pin that would only take one or two pumps of grease on my brand new E42. The dealer took it to the shop and pulled the pin. It wasn't oriented properly, all they did was rotate it - at least that's what they told me. It still doesn't take grease as easy as the other pins but at least I can get grease out the ends.
Are the grooves dead center in the bushing ? Sorry, but I had to ask.
Is the pin really tight in the bushing?
I put the linkage back together greased it as much as it will take. Will see how it wear in over a few hours.
The pin can be turned by hand. Moved in and out by hand of the various bushings.
Does this thing have grease seals next to bushing? If so did you put them in backwards?
It has a grease seal on each side of the ram end. The seals with rubber side are to the inside and the metal side that I can tap with a hammer is on the out side.
I assume that you fitted new seals when you fitted the bush.? From your description it sounds like the seals are installed back to front. They should have the rubber lip to the outside to allow grease out but not allow dirt to get in. What’s happening right now is that when you try to pump grease into the joint the lips of the seals press tight against the pin and you have a hydraulic lock. That’s why you can’t get more than pump of grease into it before everything goes solid.
To prove Nige's theory, lift the seal lip with something small... toothpick or pin... just enough to allow grease to escape. If you can then pump grease in... you have the answer. A photo of the pin & seal might have given you the answer days ago. As Tinker suggested in post #4
Sometimes its the simple things like nige said sounds like you got them backwards.
I disassembled the pin and noticed I had the seals reversed so I flipped them and reassembled then tried to grease the bushing it took grease like the old bushing. Thank you all for your help much appreciated. Yes it was a simple fix, BUT I did not know the fix.