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Hitachi ex60 final drive

L

lminter240

Well-Known Member
Joined
Jul 1, 2009
Messages
67
Location
Bergen County, New Jersey
Occupation
Electronic Diesel Engine Specialist
I RE-SEAL FINAL DRIVE PUMP, AFTER MOUNT STILL LEAK BEHIND SPROCKET
WHEEL, yo know if the leak is from hub planetarium ???????
Thanks for Helphttps://www.heavyequipmentforums.com/Forum/images/smilies/drinkup.gif
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
I have an EX60URG and I'm having issues with one of the drive motors also. The issue I'm having though is that the left drive motor continuously blows the mechanical seal. I've removed and replaces the seal group 3 times now only to put it back together and travel about 100 ft or so and it happens again. It's getting old real quick. I am to the point where I have to believe that the hydraulic system is filling the gearbox and then blowing out the seal. Someone I know, not very well, told me that it could be the relief valve is plugged or stuck and the motor builds enough pressure to do this because the fluid can't return to the tank. If it can't get back to the tank it then builds enough pressure to push through into the gearbox and then blows out the mechanical seals. The seals are pretty expensive (over $300 for the set) and I've done them 3 times already. Anyone have any insight enough to explain what's going on with my machine?
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
I just read that thread, but my case doesn't have a drain. It has 2 large lines and one small one but none appears to be a drain. All 3 lines run back to the machine. Also, just last year (prolly 30 hours) I had this motor rebuilt by the dealer in my area (W.I. Clark) when I first had this problem. When I put it back together it only lasted about 30 hrs before blowing out the seal again, and now I've resealed twice since only to roll about 100 ft or so before it happens again.

Anyone have any insight into the pressure relief valve testing? I'm just not sure whether this valve would be located in the motor itself or is it a part on the machine?

Thanks,
Brian
 
C

cps

Senior Member
Joined
Jul 13, 2008
Messages
811
Location
Ireland
Occupation
plant mechanic
it has to have a case drain, the small line is most likely the drain! Unless some one has blanked the drain line off as this would cause it to blow the seal!
I m not sure of the setup on the urg models but il have through some manuals i have to see if i can find any thing!

Maybe if you could post a picture of your drive someone on here could help

cps
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
The drive has 2 large lines and a smaller line so I would assume that the 3rd line is a case drain. I talked to a friend who put me in touch with a friend of his who works on heavy equipment and he told me 2 things to try. He said if that 3rd line becomes plugged somehow, the case would not be able to drain back to the tank and would eventually build some pressure and possibly blow the seal, but because it happens so fast he doesn't think that is the case. He does want me to blow some air into that line and make sure it is clear back to the tank though. What he thinks might be the cause is the d-rings that seal the shaft from the motor into the gearbox. He wants me to remove the whole setup again and just reinstall the motor without the gearbox attached and see if hydraulic oil comes from the seal around the shaft, so that's what I'll be doing as soon as I get a chance. I'll post the results when I do that.

Brian
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
Oh, also, he said that if the pressure relief valve was somehow plugged, the pressure might build to a point where it would blow the seal, but it also would not turn the motor because there would be no flow, which seems to make sense.

Brian
 
K

KenAl

Well-Known Member
Joined
Mar 30, 2007
Messages
194
Location
north
georgeorge said:
I have an EX60URG and I'm having issues with one of the drive motors also. The issue I'm having though is that the left drive motor continuously blows the mechanical seal. I've removed and replaces the seal group 3 times now only to put it back together and travel about 100 ft or so and it happens again. It's getting old real quick. I am to the point where I have to believe that the hydraulic system is filling the gearbox and then blowing out the seal. Someone I know, not very well, told me that it could be the relief valve is plugged or stuck and the motor builds enough pressure to do this because the fluid can't return to the tank. If it can't get back to the tank it then builds enough pressure to push through into the gearbox and then blows out the mechanical seals. The seals are pretty expensive (over $300 for the set) and I've done them 3 times already. Anyone have any insight enough to explain what's going on with my machine?
Click to expand...
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.
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
Thanks KenAl... you hit the nail right on the head. The 2 D-rings on the brake piston were toast. replaced those and the duo-cone seals and all is right again. Now I have a separate problem though. After I refilled the Hydraulic reservior (it took 10 gallons) I have no hydraulics on the right joystick. All the hydraulics work from the left joystick, the blade control, and the split boom hydraulics work also, but no hydraulics from the right stick at all. Also the left drive motor works(the one I just fixed) but the other one does nothing.

Anyone have any ideas where to start with this problem? Do I need to bleed air from somewhere? Not sure where the problem lies here. I was able to use the boom to raise the machine off the ground to put the track back on before I refilled the fluid, but then after i put the track on I shut down the machine and refilled the fluid. Then this problem started. I'm stumped.

Brian
 
K

KenAl

Well-Known Member
Joined
Mar 30, 2007
Messages
194
Location
north
You must have no pressure to that quad valve. Check your pressure coming off the neutralizer. Or swap the pressure feeding the left with the right and work from there.
 
G

georgeorge

Member
Joined
Sep 29, 2010
Messages
6
Location
CT
After swapping pressures I found that the back half of the main pump was not pumping so I pulled it off and ripped it apart. What I found was that the whole turret of pistons in the back half was shattered and one of the brass piston heads was missing.... found much of it in the bottom of the case. So now the pump is out at a hydraulic pump rebuilding business here in CT and I should have answers shortly whether or not they think it's worth rebuilding or replacing. To get the pump off required removing the counterweight.... what a job that was. That was the worst part about it. I had to torch the 2 large bolts off so now I'll have to replace those when putting it back together.
 
Y

YSD2763665

New Member
Joined
Nov 11, 2010
Messages
2
Location
china
The fuel system on most diesel engines is composed of three main parts: the injector, the injection pump, and in some cases, the engine control unit (ECU). In most diesel engines, fuel injectors are mounted in the engine's cylinder head(s), and the tip or nozzle of the injector sprays directly into the combustion chamber. In many cases, the injector is mounted just like a spark plug would be in a gas engine. But unlike fuel-injected gas engines that inject fuel at 10-60 psi, diesel fuel-injection systems run in the 10,000-30,000-psi range.
yellow stone diesel parts plant.
 
J

jagrace

New Member
Joined
Nov 23, 2010
Messages
1
Location
ireland
Cps

Hi CPS,
I see you are based in Ireland i am haveing trouble repairing a damaged final drive from my hitachi MU 5.8 digger. would you be able to put me in the right direction for replaement parts or someone that could carry out a repair or source a replacement? I am at a loss at this stage !!!!!!!!
 
C

cps

Senior Member
Joined
Jul 13, 2008
Messages
811
Location
Ireland
Occupation
plant mechanic
Call me!

I,l send you a pm with my mobile number and contact info, I,m based in county Tyrone give a call and might be able to do some thing!
 
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