Hydraulic Safety Valve

[andy_jordan]

Does anyone know how the hydraulic safety valve works? I am having a problem with my 3pt hitch - it will lift fine, but will not remain in the raised position - it immediately drops until the mounted implement (skidding winch) is on the ground. The selector is in the P position, and everything else seems OK - flow rate can be adjusted without problems etc.

It is pretty cold right now and I am thinking that the safety valve might be kicking in because the oil is too cold, and therefore too thick. I only used the tractor to clear snow yesterday, so it was only running for 20 minutes or so, but I didn't notice any improvement - I had to hold the 3pt hitch in the raised position.

Does anyone know if these symptoms are likely caused by the safety valce, or is there likely to be another problem??

Thanks,

Andy

 

[ZETORMATIC!]

YOU NEED TO PUT THE SELECTOR IN (M) POSITION . (P) IS ONLY TO BE USED WHEN PLOUGHING IT IS VERY DANGEROUS TO USE HYDRAULICS IN (P) FOR NORMAL WORK THEY CAN LIFT AND DROP WITH OUT WARNING AND CRUSH YOUR LEGS ECT...!! THERE IS NO SUCH THING AS (SAFETY VALVE) IN ZETORS??? I DONT THINK?

 

[andy_jordan]

I don't think so Zetormatic. There are 3 positions - moving from front to back Draft, Mixture and Position. Draft is the ploughing setting that essentially moves the 3pt in relation to the tractor to try and keep the plough level. Position setting allows the height to be adjusted using the height lever - the outermost one - which is what I was doing yesterday, but having to hold in position. The M is a mixture of D & P.

There definitely is a safety valve in the hydraulic system - the manual even makes mention of it, I'm just not sure whether what I am seeing is the evidence of it working.

Andy

 

[Bjarne]

If the lever koms forvard,There is a nut under the kabfloar that neds tihtning. It can be aksest from the rear of tracktor.

 

[Renze]

i think your lift cylinder piston rings are shot.
The safety valve on the lifting circuit itself opens at over 200 bar so it rarely opens, only when you drive on a road and hit a pothole with a high load on the lift.. i dont think it's this one.

 

[lspringeradelphianet]

You can see the hydraulic relief valve in this picture. It is the black cylinder.

popeye

http://www.farmphoto.com/photography/LargePhoto.asp?u=http://www.agrisurfer.com/mirror.aspx?dt=/attachment/size_original/482FE5E7-5AD0-4414-8424-E77B6DBD10DE.jpg&w=800&h=600&s=Re%3A+6245+New+Hydaulic+Pump

 

[Renze]

Popeye, that is the main safety valve. It only blows off the excessive pressure of the pump pressure.
There is another safety valve (same valve but i shim added under the spring) mounted on the 3pt lift cylinder. When you dont operate the 3pt lift, the lifting circuit is not in connection with the safety valve at the pump. Therefor, there is another safety valve to save the lifting cylinder from excessive shockloads.

 

[bernard]

There is a spring that attaches to the lift lever inside the housing that covers the linkages if this breaks the lift lever will keep sliding forward ,the lift goes down.

bernard

 

[andy_jordan]

Well I have an update and am now even more confused. I haven't had a chance to investigate further as the tractor is outside and I haven't got to it until it has been dark the last few days, but last night I had to clear more snow, I lifted the 3pt and it just stayed exactly where it should - no problems at all. I'll check into a selector problem on the weekend and keep my fingers crossed that the cylinder is OK, but now I am really confused. The only noticeable difference was that it was a few degrees warmer yesterday.