Hydraulic Lift 4911

[quinny]

I done seals and oil ring in lift ram and replaced the two o rings on the main supply pipe. When i lift arms, they raise but start jerking up and down an inch or two very fast and wont stop. Any ideas as to the problem, thanks

 

[ixer0]

Hi

When they are jerking do you have the top link connected to a machine ? When you stop the engine do the arms drop ?
It could be the "diff valve" is broken or the 'o' ring on the diff valve. This is the valve which runs across the main control chest held in by a snap ring each side. You have to lift the top cover and remove the black box to strip it out.

Mike

 

[quinny]

Hi Ixer,

Thanks for your post. thats exactly what is happpening, not too sure on how to fix it though. Do i take complete cylinder/ram out first to get at the box, would you have any photos or instructions on how its done ?, Do i take the complete box out or can it be done without removing it ?, thks again for your help

 

[ixer0]

Hi Quinny

No pictures i'm afraid.
Top cover off first, then lift cyl out, 2 'c' clips to take off linkage, undo pipe from black box to top cover, 2 large unions out from the outside of top cover where spool valve pipes attach, 13mm headed bolt near unions and wriggle the box out - as easy as that !!!! Diff valve has a snap ring either side on its end caps. Make sure you take note of which way it comes apart.

Mike

 

[quinny]

Hi Ixer,

Got the box out no problem thks. The snap rings now, how do i remove them ?. Can you buy a complete differential valve assembly, where ?. Should i replace other parts while i am in this deep, what do you think ?.Thanks again for your assistance

 

[ixer0]

Hi

Thread a small bolt into the end cap and push it in a little. The clips will flick out with a screwdriver. I have direct access to Zetor UK for spares. Where are you ? Email me if I can help .

Mike

 

[sih]

Hi,
Sorry to barge in,but I have a similar problem on my 5711-the arms will lift,and pulse with an implement lifted(sometimes slow to lift at all when tractor is facing down hill) but when the engine is turned off the arms drop? The ram seals you sent mike made it better,but its still iffy.Any ideas?

 

[sih]

Meant to say-would the proceedure be the same for a 5711?

 

[ixer0]

Hi

You have the same setup on your 5711 so it could well be the diff valve or 'o' rings.

Mike

 

[sih]

Great! - at least I know what to do now then-thanks again Mike.

 

[sih]

Hi again,
Did all you said,put a new O ring on the diff valve(is there meant to be just one on it? looks like a smaller one could be fitted too?) and on the end cap (did it all with the block attached to the top cover still,which was foolish probably as I only got out the valve,spring and cylindrical solid lump of steel).Put it all back together with new washers.Works better,jolting has stopped,but the arms drop under load still after 15 mins.
Have I just wasted my time!?