D8H46a blade won't lift

If the tank is running very hot, you have probably got a seal blown between the spool valve and tank, maybe the main feed in, could also be the main relief valve is jammed open?

Hi, Au7edd.
I had that happen to me once - a VERY long time ago - with one of the early side tank 270 HP D8Hs, just suddenly would not lift the blade off the ground. Being a contrary sort of individual, I thought to myself, "Self, if this thing won't lift the blade up, will it still push it down?" So I pushed the lever forward to force the blade down and, lo and behold, it did push down. Then I tried to lift it again and , wonder of wonders, up it came. And it never, ever did it again, at least not to me.

All I can think of in my case is that one of the quick drop valves in the tops of the rams was stuck open and letting oil pass through until I pressurised it the other way and it came unstuck.

Dunno if it'll work for you. That hot hydraulic tank could well indicate something a little more serious, like a blown seal or a worn spool valve bypassing. A worn pump would likely make the oil hot too.

Just my 0.02.

Need more info, lots of possible sources.
How hot is hot?? there is no oil cooler.
Blade and ripper pump circuit relief is 2500 psi, tilt 2400 psi.
What have you got for leaks?
Is the pump making noise?

Hi au7edd,

What is the serial number of the tractor, as there are many changes from the start number to the last, it will help others identify possible solutions to your problems.

No hydraulics, maybe a stripped spline in the pumps if it is the later tractor with the Vickers cartridges.

The Mad mouth From The South

It tries to lift the ripper, it tries to lift the blade, the tank is getting hot, so oil is being moved, if the rams are not getting as hot as the tank, the oil is not reaching them====so the problem is in the tank. I have walked up to many D8H and D9G tractors with a 'lift' problem and soon got to know that checking for any heat source soon showed the location of the problem.

Need more info, lots of possible sources.
How hot is hot?? there is no oil cooler.
Blade and ripper pump circuit relief is 2500 psi, tilt 2400 psi.
What have you got for leaks?
Is the pump making noise?

Hi au7edd,

What is the serial number of the tractor, as there are many changes from the start number to the last, it will help others identify possible solutions to your problems.

No hydraulics, maybe a stripped spline in the pumps if it is the later tractor with the Vickers cartridges.

The Mad mouth From The South

[quote="Wombat"]Hi au7edd,

What is the serial number of the tractor, as there are many changes from the start number to the last, it will help others identify possible solutions to your problems.

No hydraulics, maybe a stripped spline in the pumps if it is the later tractor with the Vickers cartridges.

The Mad mouth From The South[/quote]

the rippers will lift slowly cold, very slowly when hot. the blade rams will move slightly up and down but will not lift the tractor up nor will the blade leave the ground. I'm not to sure what the serial number is

There is a leak inside the tank most likely the main supply into the valve from the pump, or possibly MRV failed.