Plugged grease passageway

[Sodo]

Looking for ideas to clear a grease passageway.

edit: added a pic of where its plugged

This is the lower boom pivot pin on a KX41 mini-excavator. The passageways to the left side bushing (black) are plugged. Can't get any pressure because the grease passes by and out the right side.. In the pic it's wet because I've soaked it down with PB Blaster penetrating oil.

Wiggling the hydraulics, I can see movement (a little slop) in all joints except the far left side of the orange clevis. Which is OK. I removed the crossbolt and hammered on the pin, HARD, It doesn't move & will require a press I think.

Can anybody suggest any more tricks (before I get serious and press the pin out)? I don't have a press, will have to build one. The plan is to drive it to the left until the grease hole emerges, and clear it out. If I could get the joint to accept some grease without having to press that pin out, I'd prefer that.

 

[bindian]

Try greasing with the bucket on the ground and the boom lifting the machine a little. Sometimes my backhoe won't take grease and I do this. Did you try taking off the zert fitting and wiggling some small wire up in the hole. There is a tool that has oil in it that you hit with a hammer and force the oil to push the hardened grease out. I never used one, but I am told they work. The pin might move if you try the same bucket on the ground trick. Sometimes you just gotta try different positions.
hugs, Brandi

 

[Brad_Blazer]

It looks like the challenge would be to unload that joint to remove the pin. Unloaded the pin will move easier and there will be less chance of damage/danger/impossible to re-insert (i.e. if it is not moving easily don't remove it.) There may be a position with the bucket under the center of gravity of the boom that unloads the joint but if it's unsupported there is significant risk involved in driving the pin out.

Brandi's idea of FIRST trying the grease under a variety of loading conditions is a great one to overcome your path of least resistance problem. Include side loading (put the bucket down and put the swing in a little bit of a bind). There may be a condition that restricts the far side and opens up the near side. Pump the grease in a fast pulse. Maybe you can wrap some kind of packing around the far side to help increase pressure. I would squirt a whole grease cartridge through it trying this before I rigged up a hoist to drive that pin out.

 

[woodchipper]

As grease does not mary well with dust/dirt, it makes for a mixture that is gets verry hard over time; therefore restricting the flow input from fresh grease.
If no danger to surrounding seals and/or hoses, and the like, I would take the reliable torch out, and give the joint area a good warm-up. As the sludge will "liquify", dripping off may start. At this point, I would pump up the grease gun to permit further dislogement of the old packed grease. If this helps, then the pin could probably easily be dislodged. A thorough clean-up should ensue.

 

[The Suburban Farmer]

I would take the reliable torch out, and give the joint area a good warm-up.

+1 on this. I have found a good propane torch to be my best friend in cases like this. It's amazing how hard the grease can get when it mixes with dust and micro-fine dirt particles, and the heat will really help to soften it up.

 

[CDN Farm Boy]

+2. I'd remove the grease nipple and heat from the end of the pin to try to melt it all out. Keep a hose or fire extinguisher hands just to be sure. Once the dripping subsides, put the nipple back in and try to pump it up.

 

[Sodo]

Thx for ideas. I've tried every boom position imagineable. Can't use grease pressure to unplug it the grease just goes on past. Can't build pressure on the left side, unless I can figure out a way to stop up the right side. I don't know where the hole is either. This pin having two grease outlets seems doomed for failure.

Here's a pic (from my mind's eye )

I added this drawing to the #1 post to increase chances that someone can help with a trick. I've has this trouble in the past, but just had to remove the pin and clear it. But nowadays we have FORUMS! Lots of clever folks sharing tricks!

I wonder how hard it would be to drill into the center, and thread it (where the bolt plugs the passageway). Then I could try "pressure methods". And then replace the bolt with a smaller setscrew that doesn't plug it.

 

[Billrog]

If the pin isn't coming out easy it probably has a groove warn in it try turning the pin as you tap it.

 

[Sodo]

Pin is flush on each end, there's no way to get a grip to rotate it.

Easy to find a boom position where the pin appears to be "unloaded", goofing with the boom control can see it slopping in 3 of the holes - the 3 right holes. It seems to be stuck in the one left hole. Which isn't a bad deal, I think I could win if I started in on it with gusto.

For now looking for tricks - want to try to outsmart this thing before resorting to brute force.

 

[Billrog]

Isn't the pin exposed in the center?

 

[Brad_Blazer]

How about a pressure washer? Hit the seams in the joint then go for the grease hole with the zerk removed. It should have enough volume to build some pressure on the near end.

 

[sixdogs]

Good ideas so far. Heat has worked for me as has spraying penetrating oil in and then hitting with a blast of high pressure--170 psi-- air from an air hose. Take the fitting out. Lots of crap comes back at you from the air hose thing so wear goggles. Sometimes it takes a while but both methods have solved the grease issue for me.

 

[bindian]

I like the torch idea. Too bad welding and cutting equipment is not available to us mechanics (too many regulations) in the hangar, so I have never thought to use it at home on fittings that won't take grease.
hugs, Brandi

 

[Sprinklerman]

Another torch guy here , I have a burkeen vibratory plow ( irrigation installation) And I have had to heat up some pins this year to get the grease flowing .

 

[CDN Farm Boy]

I wonder how hard it would be to drill into the center, and thread it (where the bolt plugs the passageway). Then I could try "pressure methods". And then replace the bolt with a smaller setscrew that doesn't plug it.

That's an idea. I imagine the pin is hardened so it would be a beast to tap but in theory if you could tap in past the the plugged side tube and screw in a allen head set screw, that would stop the flow to the further one and allow the pressure to build against the first passage. Use a tap/set screw that you can get in a zerk also. If it is successful, just remove the set screw and install the zerk in the end and you are good to go. Getting all the chips from the tap out might pose a problem though.

I'd still be trying to melt it out first.

 

[2458n]

Poor design. As long as one path offers no resistance ,you know where the grease is going to go. Torch and wire seem to be best bet. Heat and pressure washer next. Large volume of water might flush some old grease out. Brake cleaner with a bend on the tip of the tube. Loading up the open side by positioning the boom will certainly help. Ran heavy equipment for a long time but a good trick evades me right now.

 

[PILOON]

Well I will jump in as well.
Heat has been my friend in these cases. Heat usually cures bad zerks as well.
With a plumbers torch you won't have enough heat to change the temper of the pins either but that dry caked up grease will turn to burning oil and all will be good again. Maybe just wrap close hoses with a wet rag as a precaution.

 

[truckdiagnostics]

Went through this with my hoe attachment for my skid steer. Didn't have a lot of luck with what was mentioned here. Pressure wash off all the extra grease then see if you can get it hot with a tourch, worth a shot. If you want it to take grease right going to end up taking it apart, know that is not what you wanted to hear. I have one still not taking grease and for the life of me don't know how I am going to get it apart. Some of them I had to put a cut off wheel on L head grinder, cut on either side of the pin, then press it out and still heat to get them out. This one I can't get blade on either side of pin. Bought it used....

 

[bindian]

Is the KX41 mini-excavator a Kubota?
hugs, Brandi

 

[dieselbeef]

heat it close to the plugged passage and pump it til its cool