Mini excavator final drive question

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

BrownDogStonework said:

This is the parts book that I have

Click to expand...

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