John Deere 4020 hydraulic pump leaking.

Deere19712020 · Jun 11, 2020

I have a 1972 4020 and I was cutting hay and hydraulic oil started pouring out around the shaft of the hydraulic pump. I shut it off and restarted the tractor and it stopped leaking. I used it again to bale and it did the same thing. I didnt loose any hydraulic functions. I restarted the tractor and there is a sort of knocking in the dash and the hydraulics are chattering and oil is still pouring out. I guess Im just wondering if I need a new pump or is something possibly stuck or plugged ? I dont want to replace the pump and have it blow out the seal again. Greatly appreciate any feedback!

Tx Jim · Jun 11, 2020

Welcome to YT
It's possible quad inside of dust shield on shaft failed from old age. Unfortunately the pump needs to be disassembled to replace the quad ring. I'll suggest to check hyd fluid level before operating any more.

Deere19712020 · Jun 11, 2020

(quoted from post at 05:37:32 06/11/20)
Welcome to YT
It's possible quad inside of dust shield on shaft failed from old age. Unfortunately the pump needs to be disassembled to replace the quad ring. I'll suggest to check hyd fluid level before operating any more.

Thank you for your time. Ill start pricing new pumps.

Tx Jim · Jun 11, 2020

You're welcome.
How many hours are showing on your tractors speed-hour meter? It's possible your tractors has low hrs the hyd pump could be disassembled/resealed for a lot less than $900+ that a hyd pump will cost.

Deere19712020 · Jun 11, 2020

It has 10,084 hours.

Tx Jim · Jun 11, 2020

(quoted from post at 10:28:22 06/11/20)
It has 10,084 hours.

Then a new after market hyd pump is probably a good solution.

matthies · Jun 11, 2020

Maybe take off the small black plastic line by the brake valve or behind it and see if you have go flow through the line. Just in case it is plugged or got kinked from pump.

caterpillar guy · Jun 12, 2020

While you're in there look at the drive coupling bushings and the drive shaft. They are known for wear. The knocking may be the shot bushings. If you can turn the pump with a noticeable slop the bushings are gone. The metal on metal is the knocking sound you hear. Usually most noticeable at start up or shut down.

Deere19712020 · Jun 12, 2020

(quoted from post at 02:19:18 06/12/20) While you're in there look at the drive coupling bushings and the drive shaft. They are known for wear. The knocking may be the shot bushings. If you can turn the pump with a noticeable slop the bushings are gone. The metal on metal is the knocking sound you hear. Usually most noticeable at start up or shut down.

Ok thank you for the tip.

John Deere 4020 hydraulic pump leaking.

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Tx Jim

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