David brown 990 lift won't lower all the way down

[JacobJ]

Hello all
New to this forum and I seek advice from some db experts out there.

My db 990 won't lower the lift arms all the way down when in height mode. When it is as low as it goes it is 43cm above ground measured from ground to center of pin hole in the liftarm. If I then flick the mode to tcu it lowers all the way down (18cm above ground).

Does anyone have a clue to what could be wrong? One thing that I suspect could maybe cause the problem is, that the sensor cable from the top link is missing, but I was in the understanding, that that cable only does something when it is set to depth mode? But is that wrong?

 

[flywheel]

What is the tcu ?

 

[little blue]

Traction control unit

 

[JacobJ]

Okay guys. Ive was looking at it just a moment ago and I noticed that the control lever seems to be bend slidely (bought the tractor 2 weeks ago, so what has happened to it in the past I don't know). I took that piece of metal of the quadrant, that holds the lever sideways so that I could push it slidely out and past the stop in the quadrant and the lift arms dropped to 26cm above ground, so thats just awesome.

But I would like to get it all the way down, so I think I need to adjust the nuts inside the control lever housing. Does that sound right?

Can I take that cover off where the control for the lowering speed is positioned without having to put a new gasket on to it? I dont have a new one on hand and here in Denmark spare parts are hard to come by. Could I make a new gasket myself if needed or does it have to be original?

 

[Oliveau]

You could just try lifting the dump valve. It is the little round knob near the selector quadrant.
I’m struggling to remember now, but I think the quadrant has 3 positions: TCU, Height, Depth?
Height is basically position control for non draft implements, Depth is draft control for soil engaging implements, and it needs the sensor cable to make it work properly. So is there any difference in lowering if you change between Height and Depth?

 

[Exfarmer]

from memory they always went lower in draught than in height control modes

 

[JacobJ]

Okay so you say that this is normal?

 

[Exfarmer]

Okay so you say that this is normal?

I believe so

 

[Captain Sensible]

from memory they always went lower in draught than in height control modes

That's exactly what my DB Selectamatic tractors do ......... Surprised me as well when I first noticed it.

 

[JacobJ]

Okay just to give an update. I went ahead and took the quadrant apart and bend the lever straight again. I installed new gaskets and went through the proces of resetting the control push rod, that is connected to the lever. It all worked for me. Now the lower all the way down in height mode.

Thanks for your inputs.