EX60URG Final Drive issues?

quillc · Mar 15, 2021

EX60URG from the early 90s.
I just acquired this machine. I'm going through it (changed the oil/filter and fuel filter today) and pulled the final drive plugs out. The final drives are full to the top and just a shade pressurized. The machine tracks straight, the final drives don't get hot and don't make any weird noises that I can hear from the operating cab.

Reading through some of the other threads on the topic (https://www.heavyequipmentforums.com/threads/hitachi-ex60-final-drive.19124/ & https://www.heavyequipmentforums.com/threads/leaking-final-drive.18745/) it appears that I probably have a leaking 'duo cone seal' and something to do with the brake piston seal.

KenAl said:
The EX60 have a separate outboard brake on the travel motor. (not integral)
When you travel, pressure is routed to the brake to release it. Very common on EX60 is that the seals for the brake piston go and every time you travel you allow main pressure to go past the piston seals and into the reduction blowing your duo-cone seals. Pull the motor out and then pull the brake piston out and change the seals. "Do both sides" as the other will be about to go. Caution when pulling the motor do not pull the head off the motor or the guts will spill out, pull the motor as a unit. Usually two bolts hold it on. Pull one out if it is long and obviously goes through the case and into the drive then pull the opposite one. If you pull a bolt out and it is short and obviously only goes into the motor case, put that one back. Sorry I don't have a breakdown.

Overall, this repair seems pretty straightforward - assuming that is all there is that is broken. Which part is the 'duo cone seal' that is referenced? It sounds like this service can be done with the track on?

Finally, it would be exceptionally helpful if someone has a lead on a service manual for a EX60URG. If not that, an EX60-1 so I can at least have the undercarriage service. This is my first excavator. Any help you may be able to provide would be great.

Tones · Mar 15, 2021

Not the Duo cone seal but the shaft seal on the hydraulic motor where the output shaft goes into the planetary hub. The way into it is by removing the motor, just drain ,flush and refill the oil in the hub.

quillc · Mar 15, 2021

Tones said:
Not the Duo cone seal but the shaft seal on the hydraulic motor where the output shaft goes into the planetary hub. The way into it is by removing the motor, just drain ,flush and refill the oil in the hub.

Thanks! So taking the motor off, I'd probably replace #40 O-ring and #41 & 44 D-rings to be safe. They all seem to be part of the motor-hub seal in some way.

Tones · Mar 15, 2021

While I'm not overly familiar with that particular drive hub I'd say yes
I've never seen a schematic of the actual hydraulic motor only the way it fits the hub but when you pull it down everything will be easy and self evident.

PS make sure you have all the plugs and caps for the hydraulics or you'll be sitting in puddle of oil when fitting the motor.

quillc · Mar 16, 2021

Tones said:
While I'm not overly familiar with that particular drive hub I'd say yes
I've never seen a schematic of the actual hydraulic motor only the way it fits the hub but when you pull it down everything will be easy and self evident.
PS make sure you have all the plugs and caps for the hydraulics or you'll be sitting in puddle of oil when fitting the motor.

I'll give it a shot. Worst case, it doesn't get any better.

I did notice today that the left side drive is also leaking out of the sprocket area. My presumption is that the pressure blew that seal as well. More to do I guess. The drive motor has plenty of power, doesn't get hot and the planetary doesn't make any weird noises.

Good call on the plugs and caps. I'll need to acquire a selection. I watched a youtube video of someone disconnecting their drive motor and it was a fair gush. The hard part about this machine is that all of the lines are hard lines all the way to the motor.

lantraxco · Mar 16, 2021

quillc said:
I'll give it a shot. Worst case, it doesn't get any better.

I did notice today that the left side drive is also leaking out of the sprocket area. My presumption is that the pressure blew that seal as well. More to do I guess. The drive motor has plenty of power, doesn't get hot and the planetary doesn't make any weird noises.

Good call on the plugs and caps. I'll need to acquire a selection. I watched a youtube video of someone disconnecting their drive motor and it was a fair gush. The hard part about this machine is that all of the lines are hard lines all the way to the motor.

The floating, or duocone (CAT) seal is two lapped metal surfaces running against each other, it's not likely blown out, so much as just releasing oil under overpressure. Drain the gearbox, replace motor seal, and run. It may well heal itself up just fine. Check it often for a while and it it's losing oil at an unacceptable rate, then open up the gearbox. YMMV

quillc · Mar 17, 2021

lantraxco said:
The floating, or duocone (CAT) seal is two lapped metal surfaces running against each other, it's not likely blown out, so much as just releasing oil under overpressure. Drain the gearbox, replace motor seal, and run. It may well heal itself up just fine. Check it often for a while and it it's losing oil at an unacceptable rate, then open up the gearbox. YMMV

I'm down for trying to do less. I'll be visiting the JD/Hitachi dealer tomorrow for seals. A couple of Orings and D rings should be easier than taking the whole final drive apart. from what it appears, I don't even have to take the final drive out. Just the motor off the backside. The only thing that appears to be a PITA is the fact that this particular machine has hard lines all the way to the motor. Getting the motor out will be an exercise in patience.

Tones · Mar 17, 2021

You can do it

quillc · Mar 18, 2021

Update: I'll need to replace the floating seal as its leaking down without pressure now. sigh. I ordered the seal this morning. After watching a few hours of youtube and searching this site, I'm not too concerned.

Does anyone know what kind of connection these machines use? They are hard lines all the way to the motor. I obviously need to plug the lines while I take the drive apart. Its not particularly obvious what the fittings are (JIC?, flat face? other?)

lantraxco · Mar 18, 2021

It will most likely be BSPP or metric special. MacGyvering is usually called for.

quillc · Mar 18, 2021

lantraxco said:
It will most likely be BSPP or metric special. MacGyvering is usually called for.

That's what I was afraid of.

I ordered a set of these Service plugs. https://www.amazon.com/gp/product/B07KKQ222H/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I'll see how it works out...

As I'm a relative NOOB when it comes to working on hydraulics, any MacGyver options that you have found successful would be welcome.

lantraxco · Mar 18, 2021

Lots of options, you can drain the hydraulic tank but that's a pain, you can slow things down by sealing the hydraulic tank filler if need be with some plastic wrap and tape or rubber bands. Those yellow plugs look just the ticket, mostly for keeping dirt and bugs out, except for drain lines which will be direct to tank more or less and will try to empty the tank on the ground. Duct tape and rags was always a popular thing. I'm sure others will have better suggestions, but you're on the right track.

quillc · Mar 23, 2021

Pulled the leaking final drive yesterday. It wasn't as difficult as I was thinking. I was expecting a gush of hydraulic fluid out of the drain line - but it was more of a trickle. There doesn't appear to be a casing drain filter on this machine. Am I missing something? Was I just mistaken that the drain line is supposed to be a straight shot to the hydraulic tank?

Tones · Mar 23, 2021

Both track drives and the slew motor have casedrains which return to tank and are all connected to each other. Not all excavators have casedrain filters but if you are using say a mower then a filter is a good option.

quillc · Mar 23, 2021

Always read the manual. The case drain is for 'pump leakage' and doesn't function as a return. The other pressure line (rear when driving forward) is the return line.

Tones · Mar 24, 2021

The case drain is for cooling.

quillc · Mar 26, 2021

Got the final drive removed. Had to buy a 36MM wrench to get the pressure hydraulic lines off. Didn't have a 12MM allen socket either to get the hydraulic motor cap screws broken loose. I'll pull the motor off tomorrow. Interestingly, the manual says to 'grease' the floating seal oring surface.

lantraxco · Mar 26, 2021

Never heard of that. Reread it with the thought they may be talking about the metal ring faces?

Nige · Mar 26, 2021

lantraxco said:
Never heard of that. Reread it with the thought they may be talking about the metal ring faces?

I agree. Usually Duo-cone seal silicone rubber rings are installed by wetting them with isopropyl alcohol. The grease would be used on the faces of the metal rings in order to prevent any leaks until the seal assembly had chance to rotate and seal.

quillc · Mar 27, 2021

Got the hydraulic motor out. The D ring seals are indeed worn out. You pull the complete motor by removing the six large M14 socket head cap screws (part 48 above). The allen is an M12. Had to go buy one. Minorly messed one up removing them (they were on there), but the dealer was happy to order one for $17 dollars.

Pulled the front plate and removed the first set of gears - and hit a snag.

There is a large 'Nut' (a threaded ring with pin holes) as Hitachi calls it (part 12 above) that requires a special tool #3129. Its a bar with a couple of pins that are 140MM apart that fits on a 1/2" socket. The nut is torqued to 362 Ft-Lbs, so I very much doubt that I'll be able to get it off without building a tool (or buying it from the dealer). There is a top tool (special tool 3131) that is simply a bar with a hole in the center that bolts down to the housing to give you something to lever against. That one is easy.

So the question is this: is there a work around to building/buying the tool? I somehow doubt that I'll be able to take it off without a tool - whether I build it or buy it. Just looking for what someone else has done.

EX60URG Final Drive issues?

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