Deere 690D hydraulic leak

[Jl88]

Hey all, I’ve got an old 690D LC that has a bad hydraulic leak at the final drive. I was hoping maybe someone here would have some experience with what’s going on. I read in the manual that it’s not necessary to drop the track to get the propel motor off but I’ve never messed with heavy equipment before so I’m not sure what I’m getting into. It streams out fluid even after you’ve shut the machine off. I took the inside cover off and the propel motor side is all dry, the leak is right at the sprocket… and it’s definitely hydraulic, you can’t even run it for more than 5 minutes without having to add fluid. thanks for any help

 

[92U 3406]

Is the final drive overfull?

By the sounds of it the shaft seal on the motor has let go, which in turn has overfilled the final drive and blew out the duo cone seal.

 

[92U 3406]

If the above scenario is what has happened, you will unfortunately have to split the track, remove the motor and final drive assembly.

Final drive will need to be completely torn down to replace the seal and the drive motor will more than likely need to be replaced. If there's enough case pressure being generated to blow out a duo cone, its likely finished.

Highly advise checking that the travel motor case drain line is clear and no restrictions in it as well. Both travel motor case drains are tee'd together at the swivel, so it is possible for a failed motor to spike the other and take it out too.

 

[Jl88]

Thanks for the reply, I’ll check the final drive fluid and report back. Doesn’t sound good though. It’s an old machine but I have enough in it I can’t afford not to fix it…

 

[Diesel Dave]

You have the option to replace the duo cone seal with the final drive housing remaining on the machine. May save you fighting a bunch of rust in the frame.
No matter which way you go, you will need to fabricate a socket to torque the bearing retaining nut when going back together. You will likely not need the socket when disassembling, a couple of raps with a bar will usually get it loosened

 

[92U 3406]

If the nut doesn't spin off freely, I HIGHLY advise cutting the nut off because the spindle is very expensive if you destroy the threads on it.

From my experience the best way to remove a binding nut is to drill a bunch of small holes in line from the threaded portion of the nut out to the edge, repeat 180 degrees over on the other side and then split the nut with a large chisel. At least then you have a very good chance at salvaging the spindle.

 

[Jl88]

Finally getting around to trying to get this fixed…

So I’m assuming that with hydraulic fluid getting into the final drive then there is for sure a seal blown on the hydraulic motor ? Or does it seal when it’s in the final drive? What I’m saying is if you removed the hydraulic motor and laid it on the ground but left the lines hooked up, it shouldn’t leak any fluid right? I know these are stupid questions but I have no idea what I’m even looking at until I get it apart and actually see it…
Thanks for the help

 

[Diesel Dave]

I don’t think there is enough slack in all the hoses to pull the motor with the hoses connected. If the hydraulic oil leak at the sprocket is as bad as you describe, you will likely see a portion of the shaft seal lip pushed out of the front motor housing when you have the motor removed.

As 92U 3406 has already mentioned, “ By the sounds of it the shaft seal on the motor has let go, which in turn has overfilled the final drive and blew out the duo cone seal. “

Just an FYI for JI88 ,the final drive is normally filled with 80W90 gear oil.
You need to address 2 problems ,the hydraulic oil leak at the motor shaft seal AND the leaking duo cone seal in the final drive. The final drive duo cone seal leak you attack from the planetary gear box / sprocket side.

 

[Jl88]

Ok guys, Im back at this again and really need some help. We finally got it tore down and “fixed”. We replaced the 2 big seals in the final drive and ordered a reman drive motor. We got it all back together today and went to try it out only to find the other side now pouring hydraulic fluid… it wasn’t leaking a drop before…. Any ideas?
Thanks

 

[Diesel Dave]

Was the final drive oil on the “other side “ at the proper level before replacing the drive motor and final drive seals.
For clarity moving forward , what side got the reman motor and final drive seals ?

 

[Jl88]

Not sure about that, I don’t think we ever checked it, probably should have though. I just took the case drain line loose from the leaking side and there was very minimal leakage, definitely not shooting out. It doesn’t make sense. I seen what an earlier poster said about the case drain lines being stopped up and I’ve seen where other machines have inline filters but it looks like mine is just hose from the motor the rotary manifold.

 

[Diesel Dave]

Did anyone disassemble the drive motor to check the condition before replacing it with a reman ?

 

[Jl88]

We put a new seal in the end of the travel motor but it still leaked so I just ordered a new one.

 

[Diesel Dave]

I would suggest to replace the motor shaft seal and cross your fingers.
.
Also double check case drain lines / hoses and adapter fittings per 92U 3406 below.

If the above scenario is what has happened, you will unfortunately have to split the track, remove the motor and final drive assembly.

Final drive will need to be completely torn down to replace the seal and the drive motor will more than likely need to be replaced. If there's enough case pressure being generated to blow out a duo cone, its likely finished.

Highly advise checking that the travel motor case drain line is clear and no restrictions in it as well. Both travel motor case drains are tee'd together at the swivel, so it is possible for a failed motor to spike the other and take it out too.

 

[Jl88]

I’ll go ahead and order a seal tomorrow and give it a shot… how is the best way to check if the case drain lines are clogged? I’m assuming all the hydraulics feed together then to the return filter?

 

[Diesel Dave]

On the top side of the machine ,the case drain hose from the rotary manifold to end point is not very clear in the parts lookup.
You will have to follow the path .
if the machine is serial number 527776 and up , it looks like all the hydraulic system drains go through 2 screens that are threaded into the back face of the hydraulic tank

 

[Jl88]

So I thought I was finally done with this, ended up replacing both drive motors with rebuilt units. We ran the machine for maybe 30 minutes on Saturday and it did great. We come back to it today, start it up and now hydraulic fluid is pouring out the final drive on the side we just got done replacing… we blew compressed air thru the case drain lines and it was returning fluid to the hydraulic tank. Possibly a bad rebuild or do we have something else going on? Thanks for any help

 

[Diesel Dave]

3 propel motors leaking , blowing out 3 final drive seals.
Will have to think on that !

 

[Jl88]

I’d sure appreciate it, im sick… I’ve had this thing sold for a couple months now but I can’t keep it going long enough for it to leave…

3 propel motors leaking , blowing out 3 final drive seals.
Will have to think on that !

 

[Bluox]

Have you checked to see if that machine has brakes and if it does do it have brake seals?
Bad Bob