David Brown Case Hydraulics

PaoniaFarmer · May 12, 2016

We have a David Brown 990 that the three point gets tired after running the tractor for a few minutes. On one of the last forums it was recommended to rebuild the pump by Elmer. Its an older 990. Could anyone help with finding hydraulic pump rebuild parts? Are there changes to the pump over the different years 990's were manufactured? If so, I can send a few pictures of the pump. Is there anything else I can check before rebuilding the pump? We bought the tractor at an auction and have changed the fluid twice in the last year we have owned it.

Thank you.

Bret4207 · May 13, 2016

If you've changed the fluid and filter and the problem persists, it may be the pump. The body is aluminum, gears steel. Those I've seen that were worn the body was chewed up, no rebuild to it.

RGMartin · May 13, 2016

You changed the fluid, but did you drop the sump and clean or change the strainer and or filter?

Do you have good pressure when first started up? Check at remotes with a gauge.

Once it quits, how long do you have to wait for function to come back? Just few minutes, or once the oil cools? Is the oil hot when it quits?

PaoniaFarmer · May 13, 2016

Bret4207 - Is it possible to take the pump apart without specialized tools to see if the aluminum body is damaged? Are all of the pumps standard for the 990? Its a 990U serial number 470186. Do you have any recommendations on where to get a pump? Thanks for the reply.

PaoniaFarmer · May 13, 2016

RGMartin- I did clean the sump and filter screen out both times the fluid was changed. I've never tried to read the operating pressure at the remotes. I'll check around with some mechanic friends before I buy a rebuilt pump.

When the three point gets soft and wont lift all the way up, the tractor has to set for quite a while for the fluid to cool before it will lift again. Any other ideas before I locate a gauge?

Thanks.

RGMartin · May 13, 2016

When it does work, does it lift at low RPMs or only if you rev it up?

You can probably pick up a 3000# gauge on ebay for not much money, then just plumb it into a pioneer male tip.

Bret4207 · May 16, 2016

(quoted from post at 21:05:49 05/13/16)
Bret4207 - Is it possible to take the pump apart without specialized tools to see if the aluminum body is damaged? Are all of the pumps standard for the 990? Its a 990U serial number 470186. Do you have any recommendations on where to get a pump? Thanks for the reply.

Pulling the pump isn't a bad job. Drain the rear end, pull it off, the pump is right there, bolted together, easy to take apart. You can still get the pump, DB parts are easier to get now than ever IME.

David Brown Case Hydraulics

PaoniaFarmer

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Bret4207

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RGMartin

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PaoniaFarmer

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PaoniaFarmer

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RGMartin

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Bret4207

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