Liebherr 731C won't move - diagnosing or loading it on a trailer while dead

[jezow2010]

Somehow I keep finding myself with dead dozers. I am thinking about buying a D600D Terex and a Liebherr 731C. Both nice looking machines with near new undercarriages and the price is basically scrap so I will not get burned too much. Basically, the owner sadly passed and no one around knows anything about the machines.

The Terex moves and starts, the Liebherr does not and the blade does not move either. I would like to spend a few minutes diagnosing the Liebherr because if it is a simple leak I might be able to fix it and drive it on the trailer vs using the Terex to push it on.

1. Where is the hydro oil for this machine to drive it? The tank on the side with the sight glasses is completely empty. There are two dipsticks under the hood - engine oil and something else. They are both ok. How do I add hydro oil to the tank on the side with the sight glasses? All I really saw was a plate on top that had a 6 bolt pattern or something in it.

2. in the event the machine is dead, what is the best way going about getting it to roll freely?

3. Are the blade hydro system and the drive hydro system the same systems? Do they use the same reservoir?

Rumor has it a hose blew or it had a large leak and that was it. The blade is chained up where it is sitting but again, the engine runs it just doesn't do ANYTHING.

Thanks!

 

[aongheas.macask]

Somehow I keep finding myself with dead dozers. I am thinking about buying a D600D Terex and a Liebherr 731C. Both nice looking machines with near new undercarriages and the price is basically scrap so I will not get burned too much. Basically, the owner sadly passed and no one around knows anything about the machines.

The Terex moves and starts, the Liebherr does not and the blade does not move either. I would like to spend a few minutes diagnosing the Liebherr because if it is a simple leak I might be able to fix it and drive it on the trailer vs using the Terex to push it on.

1. Where is the hydro oil for this machine to drive it? The tank on the side with the sight glasses is completely empty. There are two dipsticks under the hood - engine oil and something else. They are both ok. How do I add hydro oil to the tank on the side with the sight glasses? All I really saw was a plate on top that had a 6 bolt pattern or something in it.

2. in the event the machine is dead, what is the best way going about getting it to roll freely?

3. Are the blade hydro system and the drive hydro system the same systems? Do they use the same reservoir?

Rumor has it a hose blew or it had a large leak and that was it. The blade is chained up where it is sitting but again, the engine runs it just doesn't do ANYTHING.

Thanks!

1' the other dipstick is for the splitter box ( two drive pumps and one pump for blade).,Remove plate on top of tank and fill with oil thru the filter..
2' You need to remove both drive motors from final drives to tow machine.
3' they are separate systems. Drive system is closed loop and blade is open loop but both use the same resevoir.
A word of warning. The drive system is very expensive to repair ,it consists of two hydraulic pumps and two hydraulic motors and any failure of any one of these usually contaminates the system, when you remove the plate on top of the tank there will be a magnet attached to it ,some small furry type contaminates is normal but heavy contaminates signify major surgery. Is usually called for.
Good luck.

 

[jezow2010]

1' the other dipstick is for the splitter box ( two drive pumps and one pump for blade).,Remove plate on top of tank and fill with oil thru the filter..
2' You need to remove both drive motors from final drives to tow machine.
3' they are separate systems. Drive system is closed loop and blade is open loop but both use the same resevoir.
A word of warning. The drive system is very expensive to repair ,it consists of two hydraulic pumps and two hydraulic motors and any failure of any one of these usually contaminates the system, when you remove the plate on top of the tank there will be a magnet attached to it ,some small furry type contaminates is normal but heavy contaminates signify major surgery. Is usually called for.
Good luck.

Are the drive motors easy to remove? Just like a regular hydraulic motor on the inside of the cavity?

 

[aongheas.macask]

Are the drive motors easy to remove? Just like a regular hydraulic motor on the inside of the cavity?

Not easy but doable, you need to tilt the cab for access, Remove bolts on front of cab at steps on either side ,there is a hydraulic handpump on left hand side to jack up the cab

 

[jezow2010]

Not easy but doable, you need to tilt the cab for access, Remove bolts on front of cab at steps on either side ,there is a hydraulic handpump on left hand side to jack up the cab

oh boy, this will be fun getting this machine out of there

 

[jezow2010]

Not easy but doable, you need to tilt the cab for access, Remove bolts on front of cab at steps on either side ,there is a hydraulic handpump on left hand side to jack up the cab

Right now with the blade straight the width is 12 feet 8 inches. I need to get it to 12 feet or under to be legal for transport. Do you know what the width is if it is angled and how to angle the blade? It is just a manual blade angle.

 

[skyking1]

Right now with the blade straight the width is 12 feet 8 inches. I need to get it to 12 feet or under to be legal for transport. Do you know what the width is if it is angled and how to angle the blade? It is just a manual blade angle.

If it is manual then it is also self-explanatory. The push bars will have some holes so you can pull pins and swing it one way or another. If this does not help you, snap some pictures for us. Take some measurements from the hole that it is pinned in, to the furthest hole back.
Measure across that frame where the holes are located. With the width plus the offset, you can figure the angle in degrees.
Apply that angle to the 12'8" width to determine the angled width.
Do be very careful with the blade up and drive motors removed. It is free to roll over or through anything and they move surprisingly easily.

 

[jezow2010]

If it is manual then it is also self-explanatory. The push bars will have some holes so you can pull pins and swing it one way or another. If this does not help you, snap some pictures for us. Take some measurements from the hole that it is pinned in, to the furthest hole back.
Measure across that frame where the holes are located. With the width plus the offset, you can figure the angle in degrees.
Apply that angle to the 12'8" width to determine the angled width.

yeah I did the math... I need it to swing 25" on each side. I am assuming there is at least that between the holes. But I will measure when I go out there.

When I pull the pins and take the swing arms out of the holes I am pretty sure the blade is going to want to full on swing down or backwards. Any suggestions to stop this? It is a little harder with a dead machine.

 

[jezow2010]

 

[skyking1]

You can also extrapolate the angle as a ratio of the half width.

 

[skyking1]

two guys and something to hold one arm up. I suggest a cherry picker or something similar, the free end is heavy and will need to be lifted to get it apart.
When you get those arms free it will flop all over. If you were doing the blade swing as a normal operation, you have it down on the ground or some dunnage to control that part of the motion.
One solution is to hire a wrecker to come help swing the arms, and also load it. A good tow company will be able to help with all of it.
Jack the cab and remove the drive motors first. Spray down the fasteners with penetrant oil, and also give them a shock from the big hammer.

 

[jezow2010]

Well I had to leave the blade there. Pins for the angle were seized so even though I got everything loose it wouldn’t angle enough to get it in the angled position. Not a big issue though… dozers are home safe and I’ll get the blade soon on my trailer.

The Liebherr actually drove on the trailer and after about 25 gallons of oil seems to drive ok. The blade has zero function so I’ll start another thread on that. I’m guessing that’s why it was parked.