JOHN DEERE 4020 HYDRAULIC ISSUES

TEXASJD4020 · Sep 5, 2017

i have a 1966 John Deere 4020 PS diesel the tractro starts easy and runs well. the hydraulics work in D only. if i select L or LD no hydraulics at all but in D the 3 point raises and lowers quickly. the FEL works if i manipulate the levers in a specific sequence (eg scv lever forward + loader lever back = loader raises , scv lever back + loader lever forward = loader lowers). Power steering and brakes perform flawless no trouble whatsoever. trans temp rises after 3 hours or so of brushhogging what could cause this

chuck from neb · Sep 5, 2017

The load and depth control lever only affects the three point
but you might have a plug screen or filter that's causing your
other hydraulic pump problems which would affect your three
point also

Tx Jim · Sep 6, 2017

L/D mechanism needs to be adjusted following the steps outlined in JD tech manual. It also sounds as if SCV needs attention & it's valves set to spec's as FEL should operate correctly with scv lever in either forward or rearward position but not both positions. I will suggest to attach loader hyd's directly to tractor hyd's freeing scv's for other purposes.

Ragnarok · Sep 6, 2017

The rockshaft housings have a square 4 bolt plate on the bottom that is commonly broken. Can remove the load control arm adjustment plug and see it spraying oil internaly using a small flash light.

Tx Jim · Sep 6, 2017

(quoted from post at 08:12:10 09/06/17)
The rockshaft housings have a square 4 bolt plate on the bottom that is commonly broken. Can remove the load control arm adjustment plug and see it spraying oil internaly using a small flash light.

I doubt if the plate you refer to is leaking 3 pt would operate correctly in "D".

Ragnarok · Sep 6, 2017

(quoted from post at 06:23:31 09/06/17)

(quoted from post at 08:12:10 09/06/17)
The rockshaft housings have a square 4 bolt plate on the bottom that is commonly broken. Can remove the load control arm adjustment plug and see it spraying oil internaly using a small flash light.

Click to expand...

I doubt if the plate you refer to is leaking 3 pt would operate correctly in "D".

Yeh...you are right I re-read the original post and paid attention. It would seem the selective control valve is leaking internally(or three-point valve)....

TEXASJD4020 · Sep 6, 2017

(quoted from post at 22:33:33 09/05/17) The load and depth control lever only affects the three point
but you might have a plug screen or filter that's causing your
other hydraulic pump problems which would affect your three
point also

i thought the depth control lever controlled just the 3 point.
i changed the fluids and filters and cleaned the sump screen a few months ago
thank you

TEXASJD4020 · Sep 6, 2017

i plan to plumb the fel in as well ive read it helps improve performance regardless
thank you
Andy

JOHN DEERE 4020 HYDRAULIC ISSUES

TEXASJD4020

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chuck from neb

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Tx Jim

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Ragnarok

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