DB 990A Implematic Hydraulics Not Working

[LoneWolfMuskoka]

Hi

This is my first tractor and I've had it for a couple months now. I have the '65 model (Canadian if that makes a difference) David Brown 990A Implematic Livedrive with a loader. There is a 2 way diverter (not the 3 tap one that I see in all the documentation). The loader has been flaky and I haven't done anything with it yet, but it still doesn't work.

I'm having some trouble with my 3pt hitch. I've got a snow blower attachment on the hitch and was experimenting with it a couple days back to get the feel for it before I needed it (which I now do

However, the tractor stalled on me with the blower about 3 inches off the ground. It took a couple days to figure out that I needed to vent the fuel system and got it running again. However, the hydraulics won't move the blower up or down now.

My problem is that I need to get the blower down to use it properly. So I have some questions.

1) If the problem was the pump or clogged filter, wouldn't the return still work and allow the implement to be lowered?
2) Is there a way to bleed the pressure off of the ram to lower it?
3) If I run the blower lowered to the ground, with the ram allow it to raise and lower based on the ground pushing up on the blower? Or does the ram provide down force?

I have checked the fluid and it seems okay to me. Not that I have any idea what it should look like, but I can read the markings on the dipstick through the fluid. It doesn't seem milky to me.

I don't hear any difference in the noises from the pump/ram area when I attempt to raise the blower which I think I heard when it was working. But i don't know for sure what noises I should expect.

So, I need to know if I can get the implement lowered to the ground and run it that way without damaging the ram.

Thanks
Bill

 

[LAA]

How cold is it outside? Did you mean to say it is -8? If the tractor is sitting out in cold weather hydraulic system will get sluggish, if there is any water it
will be in the bottom of the reservoir and can freeze where the pump can't get prime or maybe block,a screen. If it is freezing or below you might try a
heater under the reservoir for a couple hours with a tarp to block the wind, least you will know one way or the other if that is the problem.

 

[LoneWolfMuskoka]

Thanks LAA

I will give that a try. The temps got down to about -15 C 2 days ago. It's been just below 0 C yesterday and today.

Thanks
Bill

 

[jean claude marleau]

I do have original manuals for 990 Implematic if interested. my e mail is [email protected]

 

[LoneWolfMuskoka]

Thanks Jean

I do have some PDFs of the driver's guide and an operational guide for the hydraulics. I also have a detailed repair manual that came with the tractor. If you have any manuals other than those it might be helpful.

Thanks
Bill

 

[joestewart]

Is this the repair manual you have?
Implematic Repair manual

 

[LoneWolfMuskoka]

These are much more detailed than the ones I have as PDFs, and much clearer than the book I was given with the tractor.

Thanks so much!

 

[willysz]

I had an old 990 that had moisture in the hydraulic res/tranny when it got cold the 3pt wouldn't work properly. What I did in desperation is add 911 diesel fuel treatment. Worked fine for years. Had over 20,000 hrs. on it when it started knocking and I parked it. Replaced it with another 990 of course.

 

[LoneWolfMuskoka]

As an update, I've got the tractor into my carport/tent to get it out of the rain and snow and put a propane heater to the rear end for a couple hours. The temps were above freezing for the past 2 days and nights which helped as well.

I took the oil pan off and the stuff that came out was surprisingly grungy looking. I guess the cleaner stuff rises to the top and that's what you see on the dipstick.

I'm having some trouble with the screen/filter unit. There is a single screw that holds it on, but if I turn it the entire filter spins with it. I'm not sure how to remove it without either damaging the filter or stripping the screw. I want to get it all cleaned up and put back together so it can sit for a day - new gasket material takes a day to cure properly before I fill it.

 

[LoneWolfMuskoka]

Turns out I don't need to undo the screw - the filter unit is friction fit. The screw just holds it all together.

One mystery solved!