Considering a purchase of this machine but it apparently has a leak on the swing drive. I know the people selling it and they are very mechanically competent and run a large fleet but they have had it setting for a long time and won't be making any repairs before sale. We ran it and it swings fine, no crazy play in the swing. There is some oil present on the carbody and seller indicated it was likely the swing drive was leaking. When I pulled the dipstick shown in the pic, there was not even a whisper of lubrication on it! I don't have any books for that machine so I am trying to wrap my head around the repair if that is what needs to happen. Seller indicated there is a duo cone on the output and I seem to recall these swing drives have some insanely pressed up goodies inside, holding all the forces from the entire house on it. Is this something we could pull off inhouse or do these step off into "special land"? So that is a hydro drive motor on the top, coupled to the reduction drive? Do I have that right? A pinion gear is on the bottom? Is there any way I can easily determine it is leaking? Is this exposed under the machine?
Literally hundreds of options for "325" going right back to the Year Dot. Some don't have a lower Duo Cone seal but no use guessing which one of the models you are looking at................ Serial Number.?
Sorry, this is a C model. I do not yet have the serial. I believe this is a 91 model though if that helps.
If no oil is showing on that gauge then the pinion seal is leaking . The pinion usually has to be pressed out of the gear case. The whole swing drive is pulled and dismantled on the bench. Bob
Thanks bob. I did find a crude video that at least showed me "something". I have built differentials, gear boxes, etc. Is this a pretty straight forward deal? say a 30T press get things done? I do have access to a 200T but rather not call in favors. Also, in the video did not show much but it looked like maybe the bottom bearing is just grease packed right next to the pinion and then a seal on top of the bearing? Or do I have that all wrong? Probably my biggest concern is there was some surface rust on the dip stick. That makes me want to question the bearings! I know water never got in there but it has sat for years so probably condensation, but still! At least this one is easier to get to! I have seen them pretty well buried.
Oil on the carbody? Pinion seal leak would fill the grease cavity for the turntable bearing. There is a rectangular cover, horizontal, on the table between the boom cylinder mounts. As for removal, the swing motor is typically removed first, taking care to note that the house will swing if not secured. Then the bolts from the swing gearbox to the table need removed, and Hercules or Mr Atlas usually installed them. Big, big tools and even cherrying the bolts may be required.
The oil, IMO, seems to be running around the swing bearing as there is oil sort of "around" the carbody under the bearing, and that bearing should just be grease. I guess I am just trying to add this up with a dry as a bone swing drive, and oil where it shouldn't be.
Here's the typical disassembly procedure to give you an idea. 325C model reduces the possibilities from "a lot" to only 20. A quick search show more than one swing drive Part Number, but they will all be broadly similar to disassemble.
I find it interesting that they don't show disassembly of the pinion. Just throw it all away! I was wanting to see what sort of seal we were dealing with! I am a bit confused because the bearing seems to butt up to the back of the pinion gear. Where does the seal go? It probably also stands to reason that the bearings are out, causing the seal leak. However, the sellers would not have tried to run it in the field knowing there is an issue.
The seal is located between the bearing and the upper side of the pinion, Area C in the illustration.
AH! I see that now that the flange goes with the assembly. I would wager a guess that Cat shink fits the bearings on and probably looking at possibly killing the flange just to get the bearings off. I mean, I guess you go for broke on this, but may not go well! Where did you get that drawing? Nige??????
Cat SIS. It's a snip of the Parts Manual illustration for the most common of two swing drive asemblies used on the 325C.
A UV oil dye test should help you find where where the oil is coming from
It's about the same as a Komatsu reducer. You have to gut out all the gears and planetaries, take the seal flange loose and then press the pinion shaft and bearing out of the main case. After that you put the pinion shaft in a 100 ton press with a bearing spitter between the bearing and the gear and hope the big bang comes quick. Around fifty tons is where I take it all out of the press and dismantle the bearing with a torch. Some people just start with the torch. The bearing is expensive I always thought and a try with the press was worth the risk. Good Luck!
And before lighting the blue touch paper, so to speak, just make sure you're standing well back.......... The chances are that the bearing is rooted anyway, and even if it wasn't before then pressing it with that amount of weight is likely to foobarb it.
I’m the “start with a torch” guy. I always replace that bearing anyway.
Yeah, I think that one main bearing alone is about a grand! I am used to doing spindles in CNC machines working with high precision AC bearings. A little different game, no torch but still nerve racking..... Good points guys. Just as a thought, Anyone ever try some magic seal expander stuff? This seems like a perfect application for something that can help a seal leak.
There are not short cuts to fixing that leak.