EX120 - Swing motor gear oil leak (Pictures)

[Egetebee]

Hi Everyone,
EX120.
Have two issues with the swing motor reduction gear unit.
1. The unit is leaking gear oil through the slew ring & onto the belly almost as fast as it goes in, almost...
2. The reduction gear unit housing is cracked at the bolt support flange holes but has been stable for a long time and seems to work just fine besides the gear oil leak.

I don't know if the cracked support holes are related to the leaking gear oil and was hoping to receive some constructive critique of the situation and possible repair solutions. It's a personal machine used to do some work on our lot and quite frankly running low on funds to repair these large ticket items.
I've read in several posts that the leak may be a reduction gear shaft seal which some have said is a reasonably easy repair, which I'm hoping. I don't have a problem pulling the swing motor assembly to make DIY repairs.

So the questions are, based on the gear shaft seal being located in the reduction gear housing;
1. Can the flange housing be welded?
2. Is the gear shaft seal replaced from the bottom of the unit or do I need to split the swing motor section from the reduction gear housing section?
3. Would anyone happen to have pictures of the bottom of the assembly or instructions on how to do the seal change?
4. Worse come to worse, can just the lower reduction gear unit be replaced somewhat low cost?

Any help would be much appreciated?
Many Thanks!

 

[funwithfuel]

Structural cast, broken like that is junk. You are better off finding used and making one from 2. The pinion got loose as a result the oil leaked out. Do you have locating dowels left or are they gone?
By your parts illustration, it looks like you have to press the pinion out of the bearing to access the seal and carrier.

 

[Egetebee]

Hi Funwithfuel,
Thank you for the quick reply.

So you'd say that replacing the seal and bolting the unit back down would not be a reasonable leak fix huh?... Was hoping to hear just that , oh well
I don't know about the locating dowels; do they align the motor assembly when installing?

I get the gist of what you're saying, "Replace broken parts with used...".
I'll start looking for parts now.

So, until I have the cash do the repair, is there a big problem with simply adding gear oil on the days the machine is being used?

Thank you again

 

[Bls repair]

Had one go bad on a B E 300 once so bad the pinion gear fell out went into free swing

 

[John C.]

Last time I saw one that bad the slew bearing was shot and bucking up and down. You will at the very least need a new swing gear case. I would also be concerned about the bore in the house that the case fits into. The case is usually very tight and takes some persuading either with jacking bolts or capable crane and a lot of shaking.

 

[funwithfuel]

I'd pump her full of grease and pour oil on top of that. That should protect your planetaries for a little while. As John C stated that lower bore might be boogered up. You might have to come up with some creative fitment solutions. Might. When you're ready we're here, ain't going anywhere. Good luck.

 

[Bls repair]

What I did was jack up from the bottom . If the oil comes out as fast as you put it in it will be a waste to put oil in . You could try heating grease till semi liquid and pour in or pump grease into fill and drain tube..
Fixing would be better,but you have to do what you have to do

 

[Bls repair]

Funwithfuel
Great minds think alike

 

[Egetebee]

Thank you all for the quick replies,
I feel a bit better with the input.

@Bls repair; 'Pinion drops -> Free Swing'... Man-O-Man OK, I understand the seriousness of that.
@John C. & Funwithfuel; Didn't realize the bore was something to be concerned with, Thank you for the heads up.
@funwithfuel; Grease the reduction gear unit. Ok, I can see that being a temp solution.

I've been searching for a replacement swing motor reduction gearbox and end up in China for entire unit @ $1000 bux, so there's that , heheh.
EX120 Swing Gearbox

Whaddya think?

 

[Vetech63]

LOL.....I wouldn’t trust anything from China that cheap. Get a part number for the entire unit and do a google search. There is a used one somewhere I bet.

 

[Bls repair]

This^^^^^^^x2

 

[Ronsii]

Like Vtech says... although a china one *might* last longer than yours pumped full of grease...

 

[Egetebee]

Get this, possibly found a swing gearbox assembly in Massachusetts for $1700 + Shipping ($150) =$1950.... it's made in China, hahah...

Part number for the entire unit seems to be 9111265.
If anyone has one 'laying around', just lemme know

 

[Ronsii]

I got one!!!!



but it is still on a machine we use


And I just put a new seal in the bottom of the reduction box about a year ago!!! it got too much water under it from a leaky swivel joint boot and froze which did some bad things to the seal yours looks like it had a *LOT* more water under it when it probably froze!!! either that or someone didn't assemble it correctly...

 

[Egetebee]

@Ronsii; Oh man .... I read the first line and was thrilled for like a whole second! Second line, The Thrill is Gone Good one heheh

 

[Ronsii]

There are machines getting scrapped everyday.... you just have to find one there are a lot of these machines out there so it's not like they are a rare part. So what's the deal with the broken casing on yours??? did it come loose or was it that way when you got it? you said it's been stable for a long time... does that mean you used to tighten the bolts on it every now and then?

 

[200lc1]

Had the same problem with my ex200, had grease in the swing drive when I bought it. I didn't trust that it would lubricate properly like that, and didn't want to end up eventually rebuilding it over a bad seal.
Came out and apart easily. Mine only required a new seal. Bearings and planeteries are all easy to inspect once apart. Mine's been holding oil since. I bought my manuals online from tradebit, they were cheap and covered the disassembly and reassembly well, as I recall. Looks like you have a manual, can't find the re&re section?
As far as the crack, looks like it ends at the hole, and is now relieved, if it hasn't cracked any further I wouldn't worry about it.
Best of luck, in what you choose

 

[Egetebee]

@Ronsii; Been that way since I got it and hasn't needed anything but gear oil.
@200lc1; I'll pull the motor assembly before purchasing any new parts. Have the 'Technical, Workshop, and Parts' manuals too.

Machinerytrader.com has quite a few Dismanteled & Salvage machines that should be available to pick-a-part from.

 

[Egetebee]

Question:
Regarding the removal of the swing motor assembly, the manual says to 'Shut off engine and move the levers to releive hydraulic pressure' before removing hydraulic lines.
Is it just that simple; move the cab levers around and hydraulic pressure will release?
Any Advice about the actual removal of the swing motor?

 

[John C.]

Make sure the machine is in a safe place with all the implements resting on the ground and clear of anything should they drift down if the machine is parked for a long time. Loosen the cap on the hydraulic tank so air can vent. The swing motor won't have any pressure on it but just in case leave the safety lever up, shut down the engine and then move the key to the run position, then move the control for swing back and forth. If you were removing any of the implement function hoses you would make sure the implement wouldn't move as well before you take a hose loose.