Frage 7211 Hydraulics

[smystaki]

Trying to maintain a 7211 tractor that was out of action for more than 7 years I am facing a strange issue.

The hydraulic lift can not keep upper possition all the times.

When the operator moves his hand from the lever then hudraulic cylinder retracts.
This could be 2 things.
1st Piston seals damaged and/or
2nd main Valve piston under heavy wear or a safety valve is leaking.

I have made a proper repair to the lifting cylinder but the system behaves the same way. In the operators manual there are not enough information for a manifold inspection.

Are there any documents for the 7211 hydraulic system available to any forum member?

 

[jandabua]

Englisch

When you let go of the lever of the lever slides back 0 direction setting?

untem go right where the hydraulic lever version is a fixed adjustment screw try this time! Fals I understand your problem!

German/Deutsch

Wenn man den hebel loslässt rutscht der hebel wieder richtung null stellung?

rechts untem wo die Hydraulikhebelraus gehen ist eine feststellschraube probier das mal! Fals ich dein Problem verstanden habe!

 

[smystaki]

This is exactly my problem.
The lever is moving by it self 5-6 cm and cylinder retracts.
But this way the hudraulic cylinder is continuesly under pressure and connected to the pump. Is this normal?
According my experiance, in industrial hydraulics, pump flow is returning to the tank when a movement is completed in order to avoid oil heating.

 

[Joachim]

Hello,

and sorry - i dont have the workshop manual in english. But i have it in german and ceski ... will this help?

When you repair the lifting cylinder, repair you also the safety valve and test the distributor with air pressur?

 

[smystaki]

No I havent repair the safety valve nor check the distributor. I 've just renew piston and head sealing elements of the cylinder.
A manual is always a manual and always helps.

 

[Joachim]

Ok, i can scan the hydraulik part of the german workshop manual. It has also a diagnostic part that can helps you.

Please give me a day to do that...

 

[smystaki]

thanks a lot.

 

[Joachim]

... stop!

I have found it in the "Bibliothek" here on zetor-forum.de ...

[DLMURL="http://www.zetor- forum.de/forum/downloads.php?view=detail&df_id=10"]Zetor 5211 bis 7245[/DLMURL]

66MB PDF german workshop manual for zetor 5211-7245

So i dont have to scan ...

 

[Joachim]

Hello,

after reading your posts by zetorworld - i can say, you have repaired the extern cylinder, but not the intern cylinder. See the Zetor parts manual for detailed hydraulik part pictures and infos.

 

[smystaki]

Now its more clear. Zetormatic functional descreption found here describes the operating conditions I met. I believe that the system needs only proper operation!!!!
And probably some "light" repair.
Two days ago I ploughed 20.000 sqm using position control and weel for depth control. My problem was that after lifting the equipment I had to hold the lever all the time during the turns.
I am going to check the springs as initialy sugested that hold the control lever in position.

Previous owner operated this mashine for more than 15 years using one hand to hold the lever during suspended equipment transportation! :

*For the parts manual seems that I have to wait next month to download.

Thanks again for your valuable help.

 

[Joachim]

why?

No more traffic? I can also increase the traffic here - no problem. Just say it.

 

[smystaki]

Seems that I run out of traffic.Can it be arranged to increase?

 

[Joachim]

... yes i can - there's a reason traffic from around 200 MB and each post or topic which you are writing again to new traffic.

I give you 200 MB extra.

 

[Joachim]

Short info: Zetorworld is back.
Zetorworld - from and for Zetor fans (https://zetorworld.com) (without www)
All old postings are back, same forum software like here.
Also Renze, the founder of Zetorworld is involved.