T6020 hydraulic issue

Have a T6020 that sounds like the hydraulics is under pressure all the time. Was spreading slurry recently and when I pull the lever to open the outlet it almost stalls the tractor. Also, when it's cold the tractor has no guts whatsoever.

Any ideas what this might be.

patsy_mccabe

It has closed centre hydraulics. You could connect up a hose to both sides of one of the service valves at the back. That would direct the oil pressure directly back to tank. Work the service valve then and if that takes pressure of the tractor, you know there is something wrong with the hydraulic control system.

Will make up a hose and try that, thanks.

patsy_mccabe

https://www.boards.ie/discussion/comment/120316541#Comment_120316541

You could take 2 small hoses and use a straight male to male connector to join them. No need to go crimping a new hose then.

Male to male hyd conn.jpg

Tonynewholland

https://www.boards.ie/discussion/2058286957/t6020-hydraulic-issue

The pump can stay on sometimes on them. Pulling another spool and releasing again usually works.

I've tried engaging all 3 spools, in all positions several times each thinking it might be a stuck relief valve or something, no joy there. Read online about a compensation valve or something like that.

patsy_mccabe

Video on a John Deere pump but very similar in principle to yours.

https://www.youtube.com/watch?v=N1zW16VkRMo

FintanMcluskey

Those T series were available on either closed or open centre hydraulics AFAIK.

If its load sensing (closed centre) then the problem could well be the compensator valve on the pump.

Not so easy to diagnose

patsy_mccabe

I worked with those type of hydraulic circuits for years in industrial applications. We used closed centre type pumps (variable displacement piston). Basically how they work is, the end of the pump internal pistons is mounted on a swashplate. As the angle of the swashplate increases, the pistons move in and out more and so the pump pumps more. The angle of the swashplate is controlled by the pressure that the pump sees at it's outlet. When you open a service valve for example, the pump will try and maintain constant pressure by pumping more and more oil. This is all controlled on the pump via the compensator.

In your case, the pump may be pumping at it's maximum (swashplate at a big angle) and relieving tru an internal relief valve. It's taking a lot of power from the engine to do this and so the tractor feels sluggish.

We were always told to never touch the compensator as it requires expertise and the right equipment to set.

A diagram showing the principle of how it works.

It doesn't labour the tractor when I operate the loader, steering or lift though, it's only when I use the remotes.