Case/DB 990 3pt hydraulics won't lift

wbj · Apr 17, 2016

Hi all -

I have a 1979 Case/DB 990. My hydraulics (loader and 3pt) were working doing strange things, like the loader would only go up, no matter which way you moved the control lever.

I ended up change the hydraulic filter and oil, and while I was at it, I replaced several hydraulic hoses that weren't in great condition.

I got everything put back together, and the loader works as it should just fine now. The 3pt was moving up and down as expected for a few minutes, but now it's down and it won't go back up. It just spontaneously stopped.

There are two hydraulic hoses that run from the hydraulic unit under the seat up to the sides of the loader control levers. It's possible (50/50 chance I guess) that I got these hoses reversed. I don't know if that would account for what I'm seeing or not.

If having the hoses switched is not the problem, I have no idea what to look at - any suggestions?

Bret4207 · Apr 18, 2016

Between the seat base and 3 pt control there is a sort of diamond shaped cover help on by 2 screws. Under that are 2 valve bodies. CAREFFULLY, CAREFULLY, CAREFULLY pull them out. and clean them. Make sure they move up and down freely. IIRC the one to the rear is likely the problem, there's a screen in the body that can get clogged. Carb cleaner will do the job, but you have to disassemble it. After pulling the cap screw cover under that diamond cover, the vavle bidy can be pulled by inserting something like a pencil into the treaded opening or a proper sized bolt.

The bypass valve is probably your issue-

http://www.dbtc.co.uk/index.php?module=Content&func=view&pid=320

If i screwed this up, my remember-er being iffy these days, RG Martin will be along to correct it!

wbj · Apr 24, 2016

(quoted from post at 05:32:18 04/18/16)
Between the seat base and 3 pt control there is a sort of diamond shaped cover help on by 2 screws. Under that are 2 valve bodies. CAREFFULLY, CAREFULLY, CAREFULLY pull them out. and clean them. Make sure they move up and down freely. IIRC the one to the rear is likely the problem, there's a screen in the body that can get clogged. Carb cleaner will do the job, but you have to disassemble it. After pulling the cap screw cover under that diamond cover, the vavle bidy can be pulled by inserting something like a pencil into the treaded opening or a proper sized bolt.

The bypass valve is probably your issue-

http://www.dbtc.co.uk/index.php?module=Content&func=view&pid=320

If i screwed this up, my remember-er being iffy these days, RG Martin will be along to correct it!

Thanks for your help - I found the cover and removed it - the valves have cap screws that I can't get off! I need to find a screwdriver that's about 3/4" wide I guess. I'll let you know how it goes once I get them out.

RGMartin · Apr 24, 2016

Get a hexagonal shaped cold chisel, and grind it to fit. That way you can put a wrench on it for extra torque.

Bret4207 · Apr 26, 2016

A hammer type impact driver will work too. Just go easy, I think they're aluminum.

Case/DB 990 3pt hydraulics won't lift

wbj

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Bret4207

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wbj

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RGMartin

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Bret4207

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