hi all, I’m doing a rebuild on my hitachi ex60-3. I’m going replacing the swing bearing while I have it stripped. The workshop manual says that ep2 grease should be used to lubricate the the ring gear and pinion gear, filled to the top of the gear teeth. Is there any better grade/type of grease to use for this? There is also some wear evident on the swing motor gearbox pinion shaft gear teeth, I have sourced a new pinion shaft, so I intend to replace this shaft also. Any tips or things I need to look out for when replacing the shaft on the motor/ gearbox assembly? I have studied the workshop manual and it seems like a fairly doable job, pressing out the shaft sleeve and bearing being the trickiest parts, I have a 50ton press. I have a new seal also got for it. Thanks
Good day Please see attached link may be helpful, maybe worth establishing the cause of the failure often the ring wear knocks out the swing box. File is too large to post here. https://drive.google.com/file/d/0B3CHoxRUD5qAVk5wSU9NUklhaEk/view Kind regards Uffex
Thanks for the reply Uffex. I don’t have a failure as it were, I am doing a rebuild on the machine and while I have the top half separated from the undercarriage I have decided to replace the swing bearing, it is more to decrease the amount of side to side play in the upper structure due to ring gear teeth wear, the bearing axial play I find acceptable. So this replacement is more of a prevention exercise while I have the machine taken this much apart, rather than a breakdown cure/ fix. Many thanks
Thanks for the document, Uffex. Saved for later.
Try to find a grease with molybdenum in it - it should be a dark grey in color. Given the kinds of forces the turntable sees, molybdenum should help the bearing out a lot.
Thanks for the reply, Would a graphite grease be better again, like pin and bush grease? Or is moly grease the best? Thanks
I'd stick with a standard EP, if this grease will be added to, then use the grease you'll be using for everything else. A moly grease is great for the worst case scenario where a pin and bushing has pushed all the grease out and the moly layer is all that is left to protect metal sliding on metal. This gear should never run out of grease, and won't be sliding metal on metal. If all those smart engineers at Hitachi wanted you to use moly or graphite grease, they would have told you to.
What you talkin bout Willis? Nobody does preventive maintainence, they just wait for things to fail.
Moly grease would be fine, except for your wallet, the stuff I buy is about double the price of the lithium. I cleaned mine right out on my 210, so far i've put about 15 tubes in and it's still not anywhere close to full.
Moly or graphite greases are not recommended for the swing gear tub, or the swing bearing. The reason is that too little friction might encourage the rollers in the bearing to skid. In the case of the swing pinion/swing gear teeth interface it's simply not necessary. As Delmer mentioned above, a good quality EP2 multi-purpose grease would be more than adequate for lubricating both the tub and the swing bearing. It needs to be "stiff" enough that it stands up under its own weight in the swing tub. That and getting the grease level just right so that the swing pinion carves "swirls" in the grease are the keys to keeping the swing pinion & the ring gear correctly lubricated. In response to the OP it appears as though the recommendations in the manual are spot on. Who'd have thunk it..?
Thanks for the reply All very valid points from everyone, I suppose considering the manual for this machine was written 25 odd years ago, I was thinking there may be better quality greases out there now for the job, as it recommends ep2 grease for the pins and bushes, whereas I would have thought pin and bush grease would be better, maybe not. It also recommends filling the grease right up to level with the gear teeth. Thanks again and keep the comments and tips coming, they’re all really appreciated.
There are better quality EP greases available now than there were 25 years ago. That alone would be an improvement more than sufficient for what you require.
Thinking about it. The photo below is a 400-tonne excavator I just finished assembling and the swing pinion/ring gear tub is filled with Shell Alvania EP2. Also an EP2 grease is used in the autolube system for the swing bearing. if it's good enough for a machine that size it's good enough for your machine.
I wouldn't argue with anybody using a moly grease for pins and bushings because of the metal on metal sliding friction, and they are more likely to run out of grease. On the other hand, people here have mentioned auto greasers that run oil, and the pins and bushings last almost forever.