Diesel Dave
Senior Member
ExcavatorEX60 said “I don't understand the knock pin. Do I drive it deeper and below the nut so the nut can turn? “
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Yes, drive the pin just below the nut.
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Yes, drive the pin just below the nut.
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Hitachi EX60G Gear oil leaks onto inside of sprocket as I'm filling planetary
- Thread starter ExcavatorEX60
- Start date
ExcavatorEX60
Member
92U 3406
Senior Member
That's quite common actually. Either that or the metal ring cracks.
ExcavatorEX60
Member
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?
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?
Nige
Senior Member
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.
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.
ExcavatorEX60
Member
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.
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.
Diesel Dave
Senior Member
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.
When going back together, you will need to fab the socket to torque the nut to the proper spec.
ExcavatorEX60
Member
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?
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?
ExcavatorEX60
Member
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:
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.
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.
92U 3406
Senior Member
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.
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.
ExcavatorEX60
Member
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.
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.
ExcavatorEX60
Member
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 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.
ExcavatorEX60
Member
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.
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.