Hello, I just brought home my first excavator, an EX60G. Its been seeping oil onto the inside of the sprocket since it came off the trailer and continues to leak even when its not running. When I checked the planetary it was down and took a couple quarts but while filling it I noticed it was leaking rapidly, again on the inside of the sprocket. If its leaking while sitting and not running can this only be the floating seals? I initially thought the leakage was hydraulic oil but now, as it leaks the gear oil I'm adding, I notice that gear oil smell. Could bad brake or other seals have forced the floating seal out? If so I should probably get to the other side soon. The machine sat for 10 plus years in a damp forest in northern CA and the motors were packed in mud behind the cover plates so moisture around the floating seals may have been a problem, the motor case and and lines have a lot of rust. Any advice would be greatly appreciated, I have good mechanical skills but minimal hydraulic experience so most of my understanding of the drive motor is from diagrams and other posts. Thank you
Welcome to HEF Excavator . If the brake or propel motor seals had pushed out the floating duo cone seal the hydraulic tank oil level would be very low as those seals would continue to leak. If the duo cone seal only just started leaking after you had moved the machine then I suspect the seal orings became very hard over time and or were stuck and tore when the machine was moved. If you are trying to control downtime then you might as well do the other side now as well.
By your description I'm 99.9% leaning to the duo cone seal failing. If the motor seal failed it would have kept leaking and the final drive would have been filling with hydraulic oil. The final drive likely would not have been low unless the duo cone had failed near the bottom and oil was pouring out as fast as it was leaking in past the motor seal. Add in the fact you've identified the leaking oil as gear oil as well. Either way you'll probably be pulling that final drive for repairs. You'll know more once you dig into it.
Thanks Dave and 92U its great to have experienced input on this. I would like to minimize the down time for sure, so Ill get 2x of all seals for the drive motors. I'm trying to figure out if the ex60-1 seal kits will interchange with the ex60G otherwise I have individual #s for the ex60G. Motor numbers are HMGB08CA which I see from another post is not the same as 60-1, but maybe the seal kit is? Can I do this work without splitting track? With track in place if I slack and support it near the sprocket? I have a brief project for it as soon as I can declare it leak free and instrumented, and get a seat in it, after that will have a less hurried pace. Amazing machine it rained into the cab for 10 yrs but still the throttle stalk and seat riser freed up and work as new with a week of penetrating oil and nudging. Not a single one of the heavily rusted floor bolts snapped off! I declared the 35 yo corroded circuit board too big a project for the limited gauges and idiot lights. I'm fitting a cheap diesel boat instrument panel that is: 24v, low rpm tach, moisture sealed and prewired: https://www.amazon.com/dp/B0BQJ4QQL2?psc=1&ref=ppx_yo2ov_dt_b_product_details was $150 and I see they raised the price, thought we were going the other direction. The electric system is nicely layered so the instruments appear to come off without any loss of running function except maybe the economy/power control. Ill add a big red trailer light in the cab for high temp and low oil pressure. As soon as I have a handle on the water temp and oil pressure, and the leaks fixed Ill put it to work for a busy few days, hoping Ive addressed reliability for now. It has a sad history, the machine was tipped and apparently ran until a rod went through the block. The previous owner put a good used engine in, trailered it home and parked it, so could be 15 yrs of not running much, it indicates 3700 hrs. I chained it to a tree and squared the cab and still need to do the windshield frame so I can get the glass back in. It has blade and thumb and came with the 5' grading bucket and the 18" digging. I probably have 100-200 hrs of work for it in my life time and it was cheap enough to keep with the property for convenience and freedom from rental hassles. I'm shocked how well it pulls stumps and moves boulders, my back and tractor will last much longer. We are rebuilding after the fires on a rocky property with very little dirt. It will be used mostly for grading fill, moving boulders, hammering and grabbing logs/trees. I have a vibe plate and hammer for it as well but sourced from different places and will need adaptation. A few questions: Is there a way to add a hydraulic safety cut like a modern machine? I see how dangerous it is to get in and out while its running and hydraulics are live, but I'm not sure shutting it off is a habit Ill keep up. There's a plug apparently to inspect the swing gear, should I be greasing the gear in addition to the zerks on the swing bearing or does the bearing grease spill over onto the gear teeth? What quantity of grease goes in these parts? Till it oozes out on outside? Similarly is there a drain under the swing gear to let out water that gets in? I haven't crawled that far under yet but don't see it in the manual. The thumb action is interesting, it closes as long as I hold the switch closed and stops when I release it. However, on opening, once I've triggered it the thumb keeps going (even it I release the switch) until it hits the mechanical limit or I trigger it the opposite direction. It appears its always done this because its ripped the welds on the cylinder mount until the cylinder could bottom out. I think this was to allow the thumb to retract automatically but is it normal to run the ram into its hard limit repeatedly? Thanks again for your advice and any responses to the above would be greatly appreciated as well.
You will have to split track then dissemble the final drive so you can get the hub off most likely you will find the bearing bad too
No way around it, track will need to come off. Typically you want to put a little grease in each swing bearing grease fitting, rotate the machine about an 1/8 turn and repeat until you've made a full revolution. The grease on the inside where the swing gear is really only ever gets changed if its contaminated in the real world. Usually you'll have to scrape it out into a bucket. Refill the tub enough so that the swing pinion gear is just slightly into the grease. Maybe 1/8" or so if I remember correctly. Just enough that a small amount will get squeezed up the gear faces as it rotates. Operation/maintenence manual would give you the specific info, I'm just generalizing based on previous experience.
Well good to know going in so I can get staged for it. I see the link "tool", I thought it was implying a full interference press fit but it looks like theres a circlip retaining the pin. What sort of force should I expect? Can I likely drive it with a drift and sledge? OK I will grease and rotate all the way at 1/8 turn or so. Strange I think Ive reviewed all of the service and parts manual and don't see a word about greasing. I recall seeing it somewhere and I bet its the first manual I downloaded for 60-2. Unlikely Ive found all the zerks. Somebody replaced the bucket pins with greasless and it looks like it hasn't had grease there since, hopefully there are press in bushings there. The drive bearings sound like a good idea to have on hand too. 400/side to reseal and bearings ouch, but I was expecting some seals and bushings when I bought it. Got the windshield frame squared so hopefully the glass pops in, something really demoralizing about a windshield that's half ejected from its gasket. Thanks again
ExcavatorEX60 said “Is there a way to add a hydraulic safety cut like a modern machine? I see how dangerous it is to get in and out while its running and hydraulics are live, but I'm not sure shutting it off is a habit Ill keep up” . Not sure if your machine had a pilot shut off valve/ solenoid valve from the factory or not. Sounds dangerous for sure ! You could wire in and plumb in a 24 volt pilot shut off solenoid valve such as part # 4609630 . It’s used on some on Hitachi ZX-3 and ZX-5 excavators and also D and G series Deere excavators.
ExcavatorEX60 said “ The thumb action is interesting, it closes as long as I hold the switch closed and stops when I release it. However, on opening, once I've triggered it the thumb keeps going (even it I release the switch) until it hits the mechanical limit or I trigger it the opposite direction. It appears its always done this because its ripped the welds on the cylinder mount until the cylinder could bottom out. I think this was to allow the thumb to retract automatically but is it normal to run the ram into its hard limit repeatedly? “ . Sounds to me like the switch or the solenoid controlling the thumb open direction is intermittently sticking on. Check if there is continuous power or not at the thumb open solenoid.
That sounds good Dave, Thanks. I see only the regular pilot valve on the EX60G but it does have a wire. That may be part of the fluid heating circuit control. Regardless I should be able to plumb a valve like you suggest to bypass the pilot pressure so nothing can activate. Maybe Ill start with the logic on a very new machine to make sure I understand the degree of disablement they are getting, I suspect they have worked this out to a fail proof or fail safe system by now.
Yes the thumb switch could be sticking its action is flakey even after I cleaned and oiled it. Its actually two microswitches taped together and it could be that one is normally off and the other is a toggle to give automated return, I wasn't that observant when testing it. Turned out that the plug terminal/tab at one of the fusible links was broken and discovering that got me away from the stick switch. Ill get back in and test each one. Now that you have me thinking, I recall it clicks in one direction and not the other which I thought was unintended, but maybe not. The thumb is the slowest motion by a lot so it could have been intended, but it sounds like that would be unusual. It looks like a retrofit kit.
Thanks for all the help here everyone, the feedback not only has valuable info but gets me thinking next steps. Dave, I was able to use the AVS catalog you'd suggested in prior EX60 posts to cross 60G to 60-1 and get my drive seal parts ordered in time for Friday. Even though the motors are different it appears the motor seals are identical along with bearings, planetary and group seal.
I see two concerns for getting things apart on the drive motor: 1) How hard is it to drive the master track pin once I find that circliped pin? 2) The very large bearing nut wiith really high torque 360ft/lbs. I can make a spanner if I have too but would be easier to order one if there are cheap sources. I dont know this type of pin driver does it have a convention and common sizes or is this Hiitachi only?
1) If you have a snap ring retained master pin it was a tap fit in the master links when new. If necessary a bit of heat on the links will help get it moving. 2) IIRC the socket for the final drive bearing retaining nut was a shop fabricated tool. You likely wont need the tool when coming apart. A couple of sharp raps with a medium hammer and punch should get it loosened. Of course you will need the socket when going back together.
I found the pins and it looks like they have no circlip and are maybe a taper fit. They have drift marks on the protruding side and are recessed on the other side. Ill try a bit of pounding today. Torch set is an hr away and I'm working out of my van so Ill try really hard with the sledge. I've used the punch drift method and your comment confirms I can probably get enough angle on it. I have an adjustable pin tool coming, one thats used for flange nuts on hydraulic cylinders, if it fits may save me a few hrs in a friends shop. Thank you
Take the shoe off on either side of the master. Makes for easier access.
Ah! now I don't have to find that extra long drift. I owe you an hr or two. With that clearance I could probably strap a hydraulic jack on it, but Ill start with the hammer. Thanks
Anyone know what size or standard of the orings for the drive motor pipes? The pipes for forward and reverse seem to be roughly 3/4" and have a flat face with an oring groove. The return looks to be a taper flare and no oring. The brake piston orings are definitely shot, haven't seen the floating seal yet. Fortunately no signs of running without oil everything was wet and no filings. Well see when I get to the bearings. Best scenarios is after sitting for 10+ years the brake pistons failed and just dislodged the floating seal? My new brake orings are not green, is that that a viton or something special for the sliding aspect? Will I ok with a regular buna type there? The master pin was an awkward swing and wouldnt budge and the pin spacers were missing so I decided to make that a seperate project. I ran the whole track off with some 2by4s about 5 mins after 2 hrs of flailing. Hope it goes back on OK.
ExcavatorEX60 said “Anyone know what size or standard of the orings for the drive motor pipes? The pipes for forward and reverse seem to be roughly 3/4" and have a flat face with an oring groove.” . The ORFS style o-rings on the (2) motor supply pipes should be a -12 size. The Deere part # T77858
Thank you Dave, I don't understand the knock pin. Do I drive it deeper and below the nut so the nut can turn? Its already recessed below the top face of the nut a bit but. Feels like its a very tight fit. Gears all look very clean and unworn, no sign it ever ran low on oil. Realized today that they sent a seal kit for EX60-2. So Im waiting for parts again.
ExcavatorEX60 said “I don't understand the knock pin. Do I drive it deeper and below the nut so the nut can turn? “ . Yes, drive the pin just below the nut.
Got the knock pin to budge. The oring for one of the floating seal halves was broken. Odd it looks like the oring was brittle and broke but it was still reasonably soft and springy. It failed right where the case is a bit rusty.
That's quite common actually. Either that or the metal ring cracks.
OK thanks 92U that is good to know, I cant think of another situation where Ive seen an oring loaded with a rotational force like that. The seal has a fair bit of drag in total but is maybe actually low for all the contact surface at work. Is the failure generally at the bottom where rust has formed? Ill smooth that area as well as I can. I notice the manual calls for greasing the oring and a lot of people do the opposite and solvent wash. Sounds like maybe the seal design calls for the oring to be able to creep and squirm, and perhaps thats lost when the rust accumulates. I have seals for the other side but was hoping to do just the brake seals for now and get 40 hrs or so of work in before I do that floating seal. Do they usually fail in quick succession or do people often get a lot of use before the second one fails?
You need the guide to installing Duo Cone seals that @willie59 produced a few years ago. All the information is still current. See HERE . If you have any questions after reading it come back and ask. One thing I will say right now. The surface where the Toric Ring (what you refer to as an O-Ring) sits is supposed to be rough, that's what grips the ring and provides the "spring force" to keep the two steel rings in contact with one another. Second comment. NO lubricant on the Toric Rings. The ramps and rings should be washed in isopropyl alcohol and air-dried before assembly.
I just noticed my ring gear has a reference mark that looks like the letter T. Does anyone know if this is an absolute reference to something such as Top? It could also be a relative reference that helps you clock the ring gear for the knock pin holes? Screws up my plans to punch the nut home as a torque to degree reference. Ill have to make a two hr drive for my big wrench unless the T has an absolute orientation to something on the splined housing. Also the manual seems to be implying that I should drive the knock pin all the way out then reinsert and drive it in again starting from the top. It doesnt actually say that though. I dont see any way to drive it up once its assembled. It also says use lock-tite which seems to imply removing and reinserting.
Drive the knock pin completely out. When going back together, you will need to fab the socket to torque the nut to the proper spec.
Thank you Nige, a helpful article, seems getting them inserted uniformly could be nearly impossible without the wire spacer. My Hitachi manual definitely says to grease the Toric ring so I'm a bit conflicted but the alcohol fit seems to be more common. Hitachi also suggests a bamboo spatulla as the tool and I like the idea of a wider blunt tool if I need it. I think I will do the alcohol fit as maybe it allows the oring to squirm enough to get into a relaxed position and will attract less dust, atleast until the seal passes some oil across. It sure looks like the sloped ramps is what generates the spring force driving the Toric rings back to position so I can reason why the silicone and greese method have been effective for some. It seems to be a nice self centering design with a rising rate spring pushing the faces together. Maybe ramp styles and bearing stack height vary enough that friction becomes very important in some situations but isn't a deal breaker in others? I see a video talking about Toric seals being more problematic in production because the sloped ramp machining is more complicated to produce?
Ive got the floating seal installed. I ended up converting to grease for the toric ring lubricant as the manual describes. The seal is springy concentric and has less than 1mm stack height difference around the circumference. Because there's grease on the o-ring its very easy to see it roll as I deflect the seal face. I don't see any drop of the toric seal as I deflect only a distinct roll in and roll out as it springs back. It appears that in this assembly the issue of slipping vs rolling is not occurring, at least at this stage. The range I'm deflecting it seems beyond any drum deflection and wobble it would encounter in service. There may have been some recession or slipping initially as I seated it but now I only see a roll and unroll with no t ring migration. In fact the only way I can get the t ring to recess is to push in one spot with the blunt tool and shove it off the backside of the seals lip/ramp, this is somewhat analogous to prying the seal out of the T-ring. Not having fit any other seals i cant say for sure but it seems this assembly is not suffering from an issue of sliding into the housing and not returning. It brings up some questions though: 1) Could I get this result only to have it migrate later? Part of the reason I used grease is to encourage the seal to migrate to wherever it was inclined to go without any housing drag or friction. I wanted to make it fail and I couldn't and it seems entirely captured between ramps from rest height to deep compression. 2) If I understand the gear box correctly there will be oil pooled and splattered behind the ring in service and the t ring will roll in and out with drum and bearing deflections. Isn't it expected that the t ring will be entirely wetted on the inside and rolling back and forth in this oil with some inevitable creep of oil to the outside? Maybe the dry/alcohol fit is only an installation issue but not a service issue? 3) I went to bring the two parts together and was surprised how far apart the bearings were with the seal supporting the drum weight. My initial thought was- why did you buy non dealer parts. Reflecting a bit, well you have to have some seal load and buying expensive dealer parts is an assurance but no gurantee my stack height is correct. After some searching I came across this: How to replace the final drive seal on your excavator final drive Tips on how to replace your excavator final drive seal. These seals are variously known as floating seals, lifetime seals or duo cone seals. finaldrive.eu Basically it says the combined part separation and spring force of the seal would likely prevent starting the bearing nut and drawing the parts together if this repair were done on the machine without the assistance of gravity and weight of the assembly compressing the seal. I am working without aid of a hoist so the first thing I did was ditch the sprocket and still could barely carry it to the van. Now with the lid off and gears out I can easily manage it on a table by hand but only have around 50 lbs to compress the seal and had estimated another 100 lbs would be required to bring the bearings together. So perhaps this separation is normal? I haven't calculated the seal contact force but could estimate it with a bathroom scale, I'm guessing 10-20 psi at the seal face? Considering the need to exclude dirt and resist pressure differences this may be totally reasonable or even low. Is the gear case really unvented or have I just not found it? 4) Another thing I found useful from the article above was guidance to fit and check the bearings before the seal install so you can feel or measure the bearing condition. Even with the 35 yo seal the drag made it hard to assess the bearings before disassembly so Ill back up a step and check bearings even though there original in excellent condition. I'm guessing 3 and 4 is common sense to people experienced in this operation but 3 unhinged me for a while. The weight, volumes of oil etc makes me really want to avoid redoing this, its bad enough that the other side may be coming soon. I will do the brake seals on the other side before I start using it again. The segmented breaks in the t ring seemed odd to me but 92U pointed out that's typical. Seeing the rolling action I can now see why they fail that way. I guess if your unlucky the break is at the bottom and instantly drains the case otherwise you might get a partial loss and more time to notice the leak before you destroy things, that may be what happened here.
I've rebuilt a ton of larger Hitachi finals using just white grease as an assembly lube and never had problems. CAT is absolutely anal about not using grease/oil. Isopropyl alcohol only IIRC. If your assembly instructions indicate to use grease, I wouldn't worry about it too much.
Thanks 92U, Its the uncertainty on something new (to me) that chews up loads of time so your and other members prior experiences are extremely helpful. I'm adding in what info I can find so in the future someone could go through this older machine with less uncertainty. If anyone knows a good source for apparently metric polyurethane d rings please post. Im near San Francisco and couldnt find them even though theres a guy that would literally make them. They seem obscure? My after market seal kits didnt have the correct brake piston seals- (urethane d rings) even though they cross reference to EX60-1, the kit did have some large d rings so there may be multiple models. So the dealer seemed the only source for the EX60G motor seals in mine. The drive motors look to be original are Hitachi branded and model but since the piston is not actually part of the motor the number may not be the whole story. Of course not in stock so this is a part to get early and have on hand if they havent been redone. The new seals measure roughly 119 by 108 by 5.5 and 79 by 70 by 5.5, part numbers 4092713 and 4092712 respectively. The motors in mine are hard to read but appear to be HMGBO8CA. Generic duocone seal labeled 182*210*19, installed Ok and Ill certainly report back if it fails. The bearings sourced aftermarket were 100 each and looked to be of less quality than the installed NTNs which were in nice shape so I reused them. The bearing race seats in the carrier were loose, identical fit with the new bearing so it seems to be a carrier machining issue or use issue. I dimpled one in 4 places, but would locktite if I had it to do again. Bearing size is CR 2256. Maybe not a bad idea to have a knock pin or two on hand in case its loose or lost. I spent 3 hrs looking for mine: full trash search, area search and drum disassembly. Later 2 AM turning to ice cream to sooth my lost pin/additional week delay found the pin shrinking in the freezer.
Id like to do the motor shaft seal. Can I simply split the case, pull out coupling/bearing assembly and replace the seal? No flying pistons I hope. The manual makes it look fairly simple if you aren't replacing bearings or taking the valve assemblies out. I don't have a great situation for pressing tight bearings but could definitely drive a seal. The machine seems to really be under 4K hrs does this seem premature? It seems this shaft seal has an easy life no wobbling crank nose or outside dirt, but 35 yrs is a while. Pushing the renewed duo cone out is my worry.
The generic duocone seems to have worked fine and I have maybe 8-10 hours on it with no leaks. I used grease to seat it into the hub. I did only one side but resealed the motors and brake seals on both sides. The dealer was the only place I could find the specialty D shaped urethane brake seals. Something in the swivel motor or center joint seems to be leaking now I'm losing fluid and while climbing a grade fluid is leaking from the swivel bearing. Ill start a new post for that. Thanks for all the help.