# David Brown 990 Hydraulics Problem...



## depot (Feb 25, 2016)

Greetings All!
I recently acquired a 1965 David Brown 990 with an Allied 660 front end loader. Tractor had not been operated for about two years. After some work and fuel filters changed, it starts and runs smoothly. Once started, I tried the front end loader and it would barely lift up and then would drop and not raise again. Checked the hydraulic oil and found it had massive amounts of water in it. I drained all the fluid out and replaced with the proper fluid. I then tried operating it again. The rear hydraulics work fine but I get nothing out of the front end. Might there be air in the lines? If so, how can I bleed them? I'm not familiar yet with the David Brown Implematic hydraulics and wonder if anyone may have an idea what I might check first. My next move is to get a manual for this machine. Thanks!

Tim


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## RC Wells (Dec 26, 2008)

The presumption is you cleaned and changer all the hydraulic filters.

I suspect hydro locked cylinders. Massive water usually means the machine went through a flood.

Crack one of the lines from the loader valve and see if it will blow oil when the valve is activated. If so, then you will need to bleed off every hydraulic cylinder to clear them of oil/water.


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## depot (Feb 25, 2016)

Update: Thanks for the info. We were able to get the lines clear of all air and ended up adding about two gallon more fluid. Loader now works perfectly.


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