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Swing gear grease

RobVG

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Grease in our 312 looks a little milky. How the 'heck' are you supposed to "Change the grease"? You can stick three fingers down though the cover and on the CAT there isn't even a drain on the bottom.

Since the house isn't turned at full speed all day long how much damage can water do?
 

John C.

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Just being a little milky won't hurt. Most of that sludge from Japan looks that way anyway.

There is a drain but you have to get up under the swivel to find it. It is a cover with two bolts and a real messy job to do. Basically you pull the bolts and knock the cover loose and try to slide out of there before all the crud falls. Them you tip the machine back and let the fluid stuff drain for at least a few hours. Set the machine down, reinstall the cover and you are ready to refill. Unless the seal on the swing machinery leaks you generally never mess with it.

Good Luck!
 

engineer

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Just being a little milky won't hurt. Most of that sludge from Japan looks that way anyway.

There is a drain but you have to get up under the swivel to find it. It is a cover with two bolts and a real messy job to do. Basically you pull the bolts and knock the cover loose and try to slide out of there before all the crud falls. Them you tip the machine back and let the fluid stuff drain for at least a few hours. Set the machine down, reinstall the cover and you are ready to refill. Unless the seal on the swing machinery leaks you generally never mess with it.

Good Luck!

I have a Komatsu PC-60-6 and it has an inspection hole with a cover next to the boom. I changed the milky grease and water mixture by using a 3/4" length of hose attached to a plastic pump I bought from Harbor Freight. The pump is run by a hand drill and is very inexpensive. I used a cordless drill,(my wife helped actually). She ran the pump into a 5 gal oil bucket while I moved the hose around the bottom of the tub and it vacuumed pretty much all the crud out through the inspection hole. I did not realize there was a drain. Anyway, this worked pretty good for me. It helps to put a small notch in the bottom of the hose so it is not completely flat on the end. This way it wont simply suck itself to the bottom of the tub and keep getting stuck. You can do what you can reach, then tip the machine and wait for it to slide to you, or turn the cab and do it a section at a time as the gear and tub will move.
John C. I read a post from you on another entry about the swivel leaking into the tub, and you mentioned you worked on Komatsu's. My Swing Machinery case has sprung a leak, and seems to be running out the hole in the center below the machine. I noticed this when I checked the oil level and was unable to get it to register after dumping in over 3 gallons of fluid. After I added a bit more, it came running out the hole. I am guessing the gear shaft is leaking and filling the tub I just cleaned out last year. Does this sound reasonable, or do you have another thought?
 

John C.

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I haven't worked on a 60 before but if you got oil in the swing pinion tub then you are surely leaking oil from the swing machinery. The design of those things doesn't allow draining the gear grindings off the bottom bearing and seal. The stuff gets through the bearing OK but sits on the seal and eventually wears its way to leaking. You will most likely find a groove or two worn in the pinion shaft.

A 60 is pretty tight so you will probably need some extensions for your socket set to remove the mounting bolts. If it is like most Komatsu swing reducers the pinion gear will be bigger than the seal and you have to tear the unit down completely. You might consider pulling the unit and taking it to the dealer for rebuild. It's expensive but it's hard to push that pinion out of the case without breaking the case.

Good Luck!
 

engineer

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John,
Thank you for the reply. The oil is pretty much running out as I try to fill it, so must be a pretty big hole. Do the gears usually need replacement or can you usually get away with new bearings and a seal? I think there are about 5600 hours on the machine, so says the meter. I will pull it out in any case. Just looks too tight to work on from underneath, especially since everything is covered in dripping oil at this point! I will see if I can get anything to come apart with my small shop press. Do you know of any aftermarket bearing suppliers, or places to maybe buy a rebuilt unit?? The machine is pretty old and don't want to spend a pile, if I can avoid it. It is an occasional use machine about 50 hrs a year, and used for very light work. Thanks again for your help.
 

John C.

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The swing machinery box comes out the top. There is a ring of bolts on the base of the component. Take the swing motor off the top of the box. You will likely have to pull the hoses off the motor to get it out because there isn't any room on those machines.

The gears are not a problem if they haven't broken and the box hasn't stopped moving. There are bronze thrust washers above and below the planetary gears that will have to be replaced. We never got a minimum thickness from Komatsu back then so could never trust any old ones. The bearings will even look good and I have re-used the planetary bearings over before on larger machines. The bottom bearings are a double set of cones and many times on the larger machines you have to cut them with a torch because pressing them out breaks the case. That is why I recommend taking the unit to a dealer.

It might be possible to find a used unit somewhere. It's just not likely.
 

engineer

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Think I'll take your advice, and have the dealer replace the bearings. Just hope they get the same advice, and don't break it! Thanks again for the heads up.
 

Randy88

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As to help answer the question of what does the water hurt in the swing gear case, not much until if freezes and as it freezes the ice can cut the seal on the swing gear housing and drain that oil into the lower case, the cost to replace the seal isn't cheap on any of them, I know I did it before I knew how much that small amount of water could cost, now we're pretty good at checking that before cold weather sets in.
 

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Does anyone know how much grease goes in the ring gear . I just cleaned out the trough with a shop vac now I need to refill it.
Thanks
 

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The swivel seals went on my EX200 and filled with oil. Cant find info anywhere as to how much grease to reinstall in the slew. Does anyone know if there is a spec for this?
Thank you
 

John C.

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There is usually a channel in the tub under the pinion gear and I liked to fill that channel with a couple of inches of grease and then spin the house around each way a couple of times. What you should see is a wall of grease on the center of the machine side of where the pinion gears runs. Some people makes it so that the height of that grease almost touches the bottom of the house. I usually just made sure the grease wall was at least half way up the pinion gears height. I've also never seen a spec for the kind of grease so just used the NLG2 that I was using to grease the pinned joints. Usually the grease from the factory is pretty stiff and after around 5,000 hours it doesn't flow real well into the pinion gear anymore. I used to recommend putting three or four tubes of the NLG2 tubes in spaced around the circle every year. You can actually feel the vibration on machines with dry swing pinion gears.
 

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Thanks, I've put 45 tubes in so far and it's just up to about 1/4" above that recess in bottom.
 
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