David Brown 990 hydraulics

[Anonymous-0]

I recently plowed my vegetable garden and did some brush hogging with my DB 990 and noticed that the hydraulics were very weak. I could only lift the plow up on full throttle. The hydraulic pump is good and the oil did not look bad. It was 33 degrees C (90 F) so I don't know if the heat was a problem. I have the older red tractor without a filter for the hydraulic oil. Any ideas?

 

[JV3CII]

Choked or choking suction strainer. Common enough problem on the Implematics. It's a conical brass screen and is underneath the backend of the tractor, hidden behind a round plate with about 6 or so bolts in it. Remove it and wash it out in some clean fuel. Then put it back in, and give her a try...
Post again if the problem persists.
Cheers, JV.

 

[Anonymous-0]

Thanks! I'll wash the screen and see what happens.

 

[Anonymous-0]

I had a 990 at work. It had slow and weak hyd. at one time. We found that the o-ring for the pump was bad. You have to pull the pto assy off the tractor to get to it. Also, if you have external hyd, the o-rings for that could be bad. The Hyd for the 3 point run through the external block.
HTH.
John

 

[Anonymous-0]

Also, with the screen there may be a filter. We had a hard time finding one the last time I had it apart for service.

John

 

[JV3CII]

I've a funny feeling that the filter on the Implies and early selecta's is a Crosland 505. Same filter was used for the engine on a Ford 105E Anglia. Worth checking.
Cheers, JV.