One step forward, two steps back…… in my previous post I explained my solution to my high speed travel on my 2000 hitachi ex35u not working. Well, the high speed travel engages now but only on one side and it gets stuck in high speed until I shut the machine off. the side that doesn’t go into high speed…… I’ve had the final drive on that side apart to fix something else on it that’s not related to this problem. When I had that side apart I noticed the “piston” that pushes on the swash plate to engage in high speed travel could not be pulled all the way out by hand. I’m pretty you could get it most of the way out but it would get hung up. It took 200 psi of air to pop the piston out, and when I assembled it I put the piston in the freezer to shrink it. anyways, right now that piston is the only thing I can think that could be causing my issue. But it did move most of the way so I really don’t know. anyone know why one side would get stuck in high speed and the other side not go into high speed? Everything looked excellent when I had it apart and the machine moves fine in low speed travel
Good day I suggest getting the fluid checked for contamination. Some machines drain the high speed valve via an orifice this may become obstructed. Kind regards Uffex
i really appreciate the help. The orifice you are talking about is located within the final drive? Contamination build up is possible I suppose since the high speed travel hadn’t worked in years, maybe 10 or more.
Good day RP We need a hydraulic schematic to point you in the right direction, we do not have one on file ,if you have a service manual it should be included - post a copy we can make some suggestions. Kind regards Uffex
I have a pdf of a 539 page “technical manual”. It is too large to upload, I could try to email it to you or try to look later today for the pages related to the issue. I don’t remember a “service manual” in pdf or hard copy being available when I looked. thank you
Good day RP Can you post what information you have onto a Gdrive (No file size restriction) it is free goes with a Google Email address, post me the link and access code, then we can make some troubleshooting information for you. Kind regards Uffex
Good day RP Update a contact has posted a schematic, so please be patient, we will come back with some suggestions. Kind regards
Great, I really appreciate the efforts. I just happened to stop by a hydraulic shop to deliver a malfunctioning stick saw and asked his opinion on my situation. I told him about the piston for the swash plate and how I needed to apply a lot of air to the port to push it out. He said he doesn’t believe it should’ve done that and it should’ve come out by hand. Again, it did move in and out by hand some but wasn’t able to actually pull it all the way out to remove it. He also doesn’t work on excavators often so he said it was just his opinion.
Good day RD Please see attached, normally the valve should move freely Kind regards Uffex
So the diagram is telling me that there are external Allen plugs that have restricting Orifices Behind them? Is this something where I can remove the Allen plug and clean out the parts inside? I am familiar with the plugs being there on the outside of the motor. hopefully removing the motor and inspecting the swash plate piston is a last resort, it moved to what I would say is 90% plus of its full travel but I just couldn’t pull it all the way out until pressure was applied. this has been a HUGE amount of help.
Good day RP Yes remove the plugs behind you should have an orifice most makers screw them in with an Allen key but there are variants, any obstruction to wither will prevent the high speed becoming engaged. You could use a jet cleaner take a good note what comes out from behind the plug you may well find the cause. Kind regards Uffex
Ok, I took a look at the motor and the plugs. I will need to remove to motor to be able to do the job properly on a bench. I also need to buy some plugs for the 4 hydraulic lines going to the motor. Should have it apart by the weekend, time is on short supply. cant thank you enough for the help, I will will let you know what I find
Pulled the motor. Removed two sets of plugs. One for the high speed valve and one for the brake I assume. Removed the few parts inside, inspected the tiny ports, Both were VERY clean. Didn’t see anything I could do to make it better, so I put It back together. Pulled the mini excavator outta the shop, and drove it a bit, finally engaged high speed travel and same symptoms, one side engages, one side doesn’t, and it remains that way until I shut the machine off to get full low speed back. Idk, maybe it’s air trapped in there I’m not sure, might use it for a bit to see what happens. Finally got the cab back on it for the first time in a year after taking it all apart. Next up, boring out the quick coupler/extension to accept replaceable bushings. I say extension because it’s a longer than normal quick coupler to suit the length of the main pin thumb. It was built with solid steel bushings that have play. any more thoughts on the high speed situation are more than welcome! Thank you
I'd start by removing both travel shift lines from the motors back to the tee at the rotary union and verify that fluid can pass easily through both. And, that there also isn't an obstruction in the tee itself. On one of my Takeuchi TB180FR machines, one of the speed shift hoses was installed in a manner in which the hose was crushed when the center guard cover was installed. On that one, one side was extremely delayed both in upshift and downshift.
Thanks, I’ll look into it. I did notice when high speed is engaged, and I push the lever for the travel on the track that is “stuck” in low speed, I hear a noise that sounds like restricted hydraulic flow. Happens in either direction on that side. I guess it could also sound similar to air traveling through the line. I haven’t run it enough to see if the noise goes away after a while. I do know after I’ve had the hydraulic track motor off and put it back on, the motor seems to need to purge some air for a few days…… meaning every once in a while for a week you push the lever to move, nothing will happen. Lift that side off the ground and push the lever again and it moves fine for a while until the next day. Stops doing that after a bit
Good day I suggest you make a check that the lame side is getting power and actually turning the track and not being carried by the good side. Kind regards Uffex
It can turn itself independently if that’s what you mean? And turn the machine by itself. I also resealed the center joint because the lame side was a bit slow traveling Lon distance l, I noticed it would track to that side over time. Resealing the center joint didn’t change anything. But the two motors are of different manufacturers it seems and one of the lines, a small one goes the a different location on the motor I believe has been replaced which would be the side that is acting fine. The two large and one medium sized hoses got to the same spots on both sides, the one small hose on the possible newer side gets hooked up on top with a 90* instead of on the side like the rest. now that I think about it. The side I assume has been replaced…… the smaller hose that has the 90* is getting plumbed right to the apply piston on the motor for the high speed travel, well I’m pretty sure that’s the circuit it’s plumbed to. Which means it’s operating the piston directly from where the other side just has a plug
Good day RPF I would suggest miss match drive motors creates a big question in my mind, if you measure the speed of each motor in low speed any difference will already represent part of the issue, again in low speed in both directions is it the same motor that remains lame. See attached. Kind regards Uffex
Yup, same motor remains somewhat lame in both directions
Could I try plumbing it how they have on the good side?
Could I try plumbing it how they have on the good side?
Good day RPF I suggest get the information from both motors, normally there will be a label - photo and post it to me, I will try to establish correct connections. Kind regards Uffex
Ok. The good motor does have a tag, I’ll get a pic of that but the lame one doesn’t have a tag. I believe the good one came from minifinaldrives.com
No tags at all now. There was one on the grey one……the grey one with the 90* is the one that works fine…
Good day The grey unit appears to me to be original equipment, I believe KYB. Manufacture. That of the remaining unit is not original, and I regret to inform you that it is most likely a spurious far eastern product. These can be supplied in both single speed and two speed versions, in addition to differing rotation speeds to the genuine unit. I am taking a guess you have a single speed model, however without detailed information from the manufacturer if you can find them we are in trouble confirming or resolving the problem other than suggest fitting the OEM. If the motor was fitted complete with a planetary drive, this would need to be replaced. Sorry, I cannot suggest a better course of action. Kind regards Uffex
One of them certainly has been replaced. I assumed the grey one because it did at one point have a sticker on it that said MiniFinalDrives.Com, that and the little piece of additional hose attached to the 90* fitting seemed to say it was aftermarket. Which ever one was replaced I’m gunna say it came as a unit with the planetary side since the planetary covers don’t match either. like I mentioned before I had the lame side completely apart, when I sealed it back up and asked the dealer for a new sealing wire to retain the cover the one listed for my machine did not fit. A wire from a ex70 or ex75 ended up being the correct thickness to properly hole the cover in place, so the clues certainly go both ways. Also when I had the lame side apart it did have the swash plate piston and related ports to apply it all the way into the motor….. even with this set up would it be possible the motor is not a two speed unit? im wondering if plumbing it like the good side with the 90* directly to the valve would be worth a shot, unless I run the risk of damaging something. just entertaining possibilities here really, I don’t want for it to seem like I’m at all doubting you, you’ve been a great help and are a wealth of knowledge and resources! very much appreciated. edit, I guess they could’ve both been replaced if that’s what you are saying, and that only one, the grey one, represents the original equipment.
Good day There are many good guys subscribing to the HEF forum maybe they have had a similar issue, my thoughts go in the direction of hunting down the original unit and obtaining a kit to repair or finding a machine that is being dismantled for parts. Our experience is that when replacing one of a pair do both or repair the original this applies especially to travel motors. If I can be of help iyou know where to find me. Good luck Kind regards Uffex
So throughout the restoration process of this machine I’ve taken pictures of everything. I knew I had most likely taken a picture of the tag on that motor. After lots of searching I’ve found it….. and found that I was wrong and the tag was actually on the lame side……. Here it is I have also contacted MiniFinalDrives.Com, they responded very quickly to my surprise and were willing to help. I just sent them a picture of the tag and am waiting to hear back.
That is great
Hey thanks for the thread. I have the same machine, 2000 or 2001 hitachi ex35u, that just developed a gear oil leak behind the sprocket. Similar situation where one of the final drives was replaced, but it seems like the original that is having the problem. The leaking motor is a kayaba mag-18vp-320e-1 pictures included. Pretty slow leak that just started. I'm hoping it is something I can fix. Can I pull this motor apart to fix whatever is causing the leak with basic tools? Thanks for the help and any tips.
Good day BrownDog Your post relates to a gear oil leak this is not a motor issue, most probable cause is the DuoCone or flat face seal. No special tools required, I suggest removing the unit that will make replacement a far easier task. Kind regards Uffex
Browndog, Uffex is correct, and removing the final drive is indeed the best way to service this unit, on a bench in the vertical position. Removing the planet gears and roller bearings and reinstalling is much easier this way. My parts book does not show the parts and numbers for what you need for some reason but I know the dealer can get them as long as it is an original unit. you may need more than just the rubber o ring seals. There are some large steel rings associated with the o rings that the o rings sit on and sometimes those can get rusty and pitted. Best the get some plugs for the hydraulic lines, remove the unit, take it apart and see what you need. the only tool you may need is some large snap ring pliers or make a pair of needle nose work. Everything else requires basic tools. Take pictures, and label your hoses. You may have to modify the box end of some wrenches to get the hoses off. First time is usually the hardest. You’ll also need to get a new piece of wire or steel ring (whichever the unit has) to re seal the planetary cover. If it’s a steel ring hopefully the last guy installed it correctly and you can reuse it. If it’s the wire style you’re best to get a new one.
Good day The method we endorse is as follows - remove the track - raise the machine and pack a block beneath the rollers - remove the drive motor and store in a clean plastic bag, often you will have enough flex to leave the lines connected - remove the transmission for bench repair. You can see on YouTube folk assembling these planetary transmissions, make sure the housing has not been damaged in some way a spray with crack detection compound may well be worth while however RPF207 has good advice preparing with the correct parts. Kind regards Uffex
Uffex, the hydraulic lines leading to both my original and newer drive motor are in the way of 3 of the bolts that fasten it to the planetary. It’s very possible his are the same way. I couldn’t remove anything without taking the hydraulic lines off first.
Thanks for pointing that out RPF207 my comment was from general experience and not always possible always good that you and other guys point out any comment which may appear misleading. Thanks again. Uffex
Thank you both very much for that info. Yes all the original bolts are in so I will have to remove the hoses but the fittings look okay, shouldn't be too bad. I am considering buying a new final drive to replace this one, then fixing the leaking drive and either replace the aftermarket drive on the other side or have a spare for the next time one fails. Is there a best place to buy a new kayaba final drive? I bought the machine used and have had some trouble working with the Hitachi dealer near me, they don't seem very interested in helping with an old used machine that they didn't sell. I expect fixing mine will take a long time between dealing with them and having no experience working on a final drive. I can't stop working and need the machine so getting another drive seems like maybe my best option.
Good day It maybe an option to search for a machine that is being dismantled for spares. Kind regards Uffex
Uffex, I was reading the service manual and found a bit of information that may help with part of my final drive issue. my excavator does track a bit on the right side only, the drive that the two speed doesn’t work on. When going a distance on a slightly crowned road, with the weight of the machine leaning on the “good” side drive, the result is the lame side gets quicker and tracks normal. At this point if you could read the “NOTE” in the picture provided, it mentions the main relief valve. Now that you’ve read the NOTE Another question is can a faulty relief valve also perhaps make any noise at idle after cold start or when idling and load is applied but using the boom to push the bucket on the ground??? I was using the mini to back fill and level some ground around my fathers new well he had drilled I did notice the right side seemed to be lacking torque as well when pushing with the blade
Hi RP A faulty relief valve would affect more than tour left track. Kind regards Uffex
RPF, Did you buy your service manual somewhere? I don't have one but could really use it.
Thanks uffex. BrownDog, I bought it as a pdf from ufixthis or ufixit. Something like that. If you can private message me your email I will try to send the manual to you. It’s 500+ pages. I’ve got the parts book, service manual, and engine manual for the 3LD1 that is in my machine. I just seen in your info you are located in New Hampshire, I’m in Maine
Thanks a lot. Turns out I did the same thing a few years ago when I bought the machine. I have the 200 page operators manual and a 540 page technical manual on my computer. I also have a hard copy thing labeled "equipment components parts" has major part numbers but no numbers for things like filters and maintenance items. Got any parts catalogs? Nice ya I live near Concord NH. I bought my machine in Wells Maine. What part of Maine are you in? Ordered a final drive from minifinaldrives.com. Got it Saturday morning and had it fixed by the afternoon. Perfect match seems like it will be a good unit. Really good service from them. Now to repair the kayaba that came out. Looks like the face seal opened up hopefully I can fix it
This is the parts book that I have
nice! I live in the next town over from wells, Kennebunkport. glad to hear the machine works properly. uffex, what about the case drain line? If that is blocked or kinked in any way could that cause problems with travel and speed shift?
Good day RPF You can check out the high speed line by tapping into the signal line port PS at the motor G at the central joint or go direct onto the output of the solenoid valve, see attached should have about 700 p.s.i. Kind regards Uffex
Update on my travel motor issues, not a whole lot haha. Still acting up. Slightly slow on one side, that side also since I took it apart had been getting “stuck” temporarily when I push the travel lever, machine sat all winter and the problem went away, I took it apart again for some reason and the stuck problem started again. I found one of the fittings on the pilot pump was leaking due to bad o ring, replaced the o ring and the amount that track gets stuck has going way down. High speed travel still doesn’t work on the problematic side. Have had no time to really trouble shoot it. The machine only gets used on my property. I just loaded 100-150 yards of blasted ledge mixed with gravel to raise up part of my road with it and other than that one final drive issue the machine did great. Temp gauge used to run around half way pre “restoration”. After cleaning all the build up out of everything it now runs at 1/3 on the temp gauge and that’s even on a 90*f day. I typically don’t run my machines on days over 85*f as they don’t really make me money and I don’t need to add heat stress to my machines being my newest is a model year 2000 (the excavator). got a 1995 bobcat 853 skid steer, absolute tank for its vintage. A 1999 c3500hd with Monroe 4x4 and a 9’6” dump, another tank that loves to haul for its vintage and size. anyways, enough side tracking. Still haven’t gotten to troubleshooting, wife, two kids, full time+ job, and so on.
Hey brown dog, what are you doing with the old final drive you took off?
Good day Your resolution of fixing the servo leak indicates that you have an issue with maintaining servo pressure, I suggest you double check that the pressure is good in all circumstances. Kind regards Uffex
Really appreciate the speedy replies uffex. Ill look into that. I see someone today who is a senior tech at a hydraulic shop and he says “100%” my two speed piston for the swash plate is acting up. This was his conclusion after I told him when I took the drive apart that the piston moved 95% in and out but could not be pulled out by hand and that I needed air pressure to remove it. To install it I put it in the freezer to shrink it. He says it should come out by hand. Any thoughts?
Scratch all that for now. The machine just got stuck in two speed and the lame planetary was filled with hydraulic oil…….. edit. I saw oil on the track, noticed it was coming from the crack that had been brazed. the thing about the braze job was impurities caused the braze to have 3 pin holes once completed and tested. I rtv’d the holes and they haven’t leaked until today when the case filled with hydraulic oil, the RTV thankfully let go before blowing the cover off the drive or blowing out the duo cone. The machine got stuck in high speed, concerned I began looking for oil leaks, when I saw the oil on the tracks I opened up the fill plug to the planetary case while at the 1 o’clock position and oil came POURING out. pulled the plug on the other side and it’s oil level was fine
Spoke with a tech from Finaldriveparts.Com I believe the go by Texas final drives. Super friendly staff, told the tech my story, he thinks that the case drain and the two speed line are swapped. I thought I’ve checked it before and found it wasn’t but I need to check again I guess. reason why it started causing me problems only now, the two speed never worked, solenoid valve for the had a bad coil. I tried engaging it the night before the failure and that’s when it possibly got stuck and filled the planetary case due to high pressure. Just throwing theories out there. The few times I’ve had it apart I’ve put the hoses back to where they came from. So whoever replaced the drive before maybe crossed them up, idk.
Update #987…. Found my problem, the high speed travel hose and the case drain were swapped…. ON BOTH MOTORS…… since looong before I owned it. why was the machine only recently having issues and not the years prior that it’s been like this you might ask? The 2nd owner of the machine which is who I bought it from never knew it had high speed, and it never worked until I fixed it with a new coil. I’m assuming there was never a case drain issue even with the hoses crossed because of the 20 year old center joint seals were bypassing the pressure build up until I replaced the a few months ago. Now the pressure had no where to go this the lame track motor all of the sudden not responding or getting “stuck”. This machine never had that issue when I bought it nor prior to me buying it. new center joint seals and now a two speed circuit finally putting pressure to the line only to be sending it to the case and I end up in the situation I’m in. the center joint could EASILY be turned with just a finger prior to a new seal kit. Throw the new seal kit in and I had to get a big wrench to line it up perfect due to how tight it was and there’s no doubt the seals with bypassing the case pressure. because of these circumstances I assumed the lines were all in the right spot because the machine never acted up, it just didn’t go into high speed at all due to bad coil. I shouldn’t have assumed is all it comes down to, I have all the resources in front of me to have caught this earlier. I came home today, finally compared the hydraulic schematic to the hoses on the machine and confirmed the problem. But damn, both sides swapped. I appreciate all the help, huge shout out to Uffex, this whole website owes you a beer or couple thousand beers.
Good day That is great news you have the machine fixed and informing us that you found the problem and thanks for the kind words. Kind regards Uffex
Uffex, I hadn’t actually fixed anything at the time of your last message, just made a discovery. Ive got the case drain and two speed hoses on my machine to where I “think” they belong. On the after market side I’m sure of. On the drive that seems to be an older if not original it is set up a bit different but the book shows it as correct. the two speed line goes up and over the motor and plumbs directly into what is the two speed plunger valve. And the case drain has been set up to be plumbed into a port directly between the two motor feed lines instead of high up on the motor. initially after swapping lines I had no high speed at all except once every 20 pushes of the track lever on the aftermarket side only in reverse then it’d go away, this is the side that never worked. the side that always worked didn’t at all. So I assumed there was a blown out o ring in the original looking motor for the two speed orifice. took the stinking final drive off the machine. Separated the motor from the case, o rings are fine. If they weren’t I’d have an external leak because on this motor they are placed outside of the large o ring that seals the case to the motor. now…… EVERYTHING looked excellent in the case EXCEPT…… there were no brake clutches….. the case wasn’t even machined for clutche splines nor did the plunger barrel have any machined splines for the disks. There were also no holes for any clutch springs on the face?????. How does that side apply brakes? I put it back together and ran it shortly until the older side started going into high speed on its own again. I just got a hydraulic pressure gauge and need to by some fittings and I will take reading on the two speed line and other stuff. sorry to bother you. I was severely lacking patience and covered in oil and didn’t take the time to get a pic of the lack of brake clutches. Also at this point my two speed electrical circuit doesn’t seem to be working again. I set it up so I just touch the two wires together to complete the ground for the coil so I can see the little spark and confirm there is load. There was no spark from it today meaning there was no coil load. Just venting really, I know I need to test psi
Thought about it some more. Recently my heater came on without being switched on. Took pulling the fuse to get it to turn off. My pilot controls can be operated with the lever up, and now no spark from my two speed wires….. I’m having electrical problems. My two speed solenoid must be grounded on.
Good day Please see attched the brake is hydrulic for small Hitachi machines. I do not have a wiring schematic for your machine post to me if you have a copy. Kind regards Uffex
After finding out the case drain and high speed line were crossed on one motor, I switched them back. The other final drive still wants to be in high speed all the time. The selling valve for the high speed is not energized so that not the problem, although maybe it’s stuck open, IDK. I just went to an industrial hardware store where they have 33,000+ fitting but we had no luck finding a BSP T to put in line so I could take a reading on pressure in the high speed line. The line I need to T into is a BSP #4 in size. I have a 1000 psi gauge and a 5000 psi gauge with 1/4 npt fittings I just haven’t found a way to hook them up yet. So I need help sourcing the parts. I even tried to get the parts to plumb the high speed line directly to the spring loaded two speed valve on the motor just like the other motor is set up but the shop also did not have anything in size #7 boss. The plug directly over the spring valve is #7 boss. So I need a fitting to go from #7 boss to #4 bsp female. the one final drive that has always gone into high speed is somehow getting pressure to go into high speed. I took that drive apart, all look well. I just can’t take a pressure reading to see if the pressure is coming from the high speed line. I haven’t used the machine since this problem has occurred as to not risk damage.
Trying to look online for #7 ORB fittings. I can’t find any. But the guy at the hydraulic shop tried my plug in a #6 and a #8 and it didn’t fit
Good day I'm not sure if the attached is helpful, taken from a later machine, but I would guess the fittings are the same. Kind regards Uffex
I found a chart for ORB, but it doesn’t list a size #7. The guy at the store said he places orders for #7 ORB but they never send any to him
I scrapped the idea of trying to T into the high speed line. I disconnected the high speed line at the motor that has never gone into high speed, capped the fitting on the motor. I had the shop make a hose to couple my pressure gauge onto the now disconnected high speed line. started up the machine, let it idle for a bit, tracked forward and backward, after 1 minute of back and forth travel 10’ in each direction the other side kicked into high speed like it recently started doing on its own. The pressure gauge never moved telling me it’s not a high speed line problem. I then switched on the high speed and the pressure gauge went right to 600psi at which point I shut it off before it could go higher because I only had my 1000psi gauge on it and didn’t want to risk anything. Once off, Pressure dropped a bit without moving the tracks, shut the machine off and pressure went to 0. Guess I gotta check that the case drain has capable flow to the tank now. And if it does it’ll be a problem in the drive motor.
Checked case drain, clear back to the tank. called Texas final drives, they said I should should look into the two speed valve on the motor and see if the valve is ok and that there’s no cracks in the valve bore. still looking for ORB fitting to plumb high speed line directly to valve on other motor
This is an old post but I'll post my two cents and mind you I do not know a damn thing and I'm anything but a professional. The photos you posted on page 2 of this thread, the grey unit you mention working great, I believe that has the pilot line (smallest hose) in the wrong position. as it should be mounted the matching port directly opposite 180 on the valve assembly placing it on the very bottom, as this typically engages or disengages your brake and having it mounted at the top will subject the line to any air coming through the system and cause erratical and unpredictable movement responses. I noticed your case drain (medium size hose) appears to be centered between your A&B lines (the thickest 2) and typically the drain line should be at the top to catch and remove any air bubbles coming through the system, having it locate at the highest port prevents air pockets from be able to form in the drive motor. I digress I could be wrong about all this as perhaps you have a system I'm simply not familiar with it and its functions are much different than what I'm accustomed to seeing.