Ford 1920 3 point lift oscillating

[double hunter]

New to me Ford 1920 lift problems, when the lift is at any position it oscilates, it will go up to that point and drop back, go back up and drop back, about a quarter of the the way, doesn't matter if all the way up or half way up, check the fluid and changed the filter, no help, are the pumps hard to workon, any help appreciated.

 

[Soundguy]

sounds like leakdown and circuit regen. does speed change at different rpms and loads?

 

[double hunter]

The higher the rpm the faster the oscillations, the lift comes up slower than i think it should with no load.

 

[Laneman]

I have this problem on a Massey 40 I'm restoring, I have read that this is usually caused by worn or broken piston rings on the hydraulic pump. Not sure how similar the Massey pumps are to Ford, but I've seen rebuild kits that look identical for both makes.

 

[JC-jetro]

1920 has a gear driven hydraulic pump and has no reciprocating piston.

JC,

 

[double hunter]

do you think that I just need to replace the hydraulic pump or could something else be causing this.

 

[JC-jetro]

when you say oscillates it has to follow a frequency. does it happen at any given lift point? does it happen as max lift? if the pump was bad completely then lift arm would not come up. I'm thinking it might be max height lift adjustment, pressure relief mechanism failure or a check valve at the lift cylinder head causing it to burp( lose pressure and drop) and right away pump building pressure raising the lift arm. Need a more detailed description to may be pin point the problem better.

JC,

 

[Soundguy]

I have this problem on a Massey 40 I'm restoring, I have read that this is usually caused by worn or broken piston rings on the hydraulic pump. Not sure how similar the Massey pumps are to Ford, but I've seen rebuild kits that look identical for both makes.

a massey 40 and Nh 1920 are so different that virtually nothing will cross over...

 

[Soundguy]

do you think that I just need to replace the hydraulic pump or could something else be causing this.

i think you need to stop guessing and going off on tangents like repalcing the pump and focus on getting a service manual and trouble shooting the issue before you spend way too much time and money on this.

does the lift drop when you shut the machine off?

is there a point in the positiuon control travel that the oscilations stop?

we are looking for control valve and cyl / piston realative positions.. and condition of hte oring / cyl bore.

there are other possibilities like check and or safety /relief valves too.

 

[double hunter]

I'd be the first to admit I don't know jack about this, don't mind trying anything, the oscilations accur at any height, 1/2 way up, all the way, doesn;t matter, the lift arms come right up but wherever yu stop the lift the oscilations start, might ought to invest in a maint. manual
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