Vermeer TM700 Trailed disc mower - hydraulic question

[oldnslo]

Lewis,
If I am viewing your circuit correctly it appears that this is a master slave lift system. Fluid from the right cylinder is used to lift the left cylinder. If you get air in in that line between the two cylinders it will not work properly. What I don't know is if Vermeer did incorporate some rephasing feature to purge this air. This system works well to lift a cutter head evenly.

Suspect valve in that body is a relief valve to protect system from bouncing down the road. Any part numbers on that valve?

 

[lews]

Found part no. RV10-22H with and arrow pointing to the outer end. Below that 06/03, and below that 06/05. The outer end has an allen wrench fitting so it looks like it could be dissassembled (it's very tight so not an adjustment). I took apart and it's just a chamber with fluid that drips down thru the valve - not sure if it supposed to or not. I don't see how it could bleed air, but maybe you could loosen this end. I'll also try bleeding air between the master and slave. However, remember I'm able to fully retract it only on removing the valve, releasing pressure from the top of the master (left side). Maybe the valve is somehow supposed to relieve that pressure. I did find a Vermeer valve that looked just like it on Ebay for 20 bucks, so I bought it - just in case.

 

[oldnslo]

Rv10-22H is a Hydraforce factory set relief valve so do not recommend taking it apart since you have no idea on setting.

Do you have the owner - operators manual for this machine? If not I would suggest getting a copy since it would explain the rephasing if it has that feature. I believe you can register your machine on Vermeer website and then get this manual.

If my thoughts are correct on this being master - slave system both cylinders should move at the same time and same speed.

 

[lews]

I have a manual but it doesn't say anything.

 

[lews]

I have a manual but it doesn't say anything.

Oldnslo, I'm at a loss and the dealer can't help. You're right that the cylinders seem out of phase. Their "throw" seems exactly the same length. It's just one side starts at fully retract and the other starts 2" or so out from fully retracted. Except for that valve, it seems so simple, which leads me to think it is the valve (and I don't know what else to do). If the valve is allowing fluid to leak to the other side, the top side of the left cyl when fluid is sent for lifting, couldn't that prevent the cylinder from fully retracting?

Can you think of some other resource I could got to if you can't figure it out? I'm really in a jam.

 

[oldnslo]

Lewis,
Just to confirm that I am looking at your drawing and interpreting it correctly.

On the cylinders is the bottom port the rod end and top port the cap end?
One hose connects from tractor to valve block and then on to bottom rod end of right cylinder.
Top cap end hose of right cylinder connects to bottom rod end of left cylinder.
top cap end of left cylinder connects to top port of valve block and on to tractor.

Theory of operation based on above interpretation of your circuit.

To retract or lower the cutter head shift tractor valve to supply oil to the bottom or rod end of the right cylinder. Right cylinder parts to retract forcing oil from cap end of right cylinder to rod end of the left cylinder. Oil exits cap end of left cylinder back to the tractor.

Key to this working is that cap end volume of right cylinder must be the same as rod end volume of the left cylinder and this entire area must be full of oil.

If some one changed one of the cylinders to a different size the system will not work.

The relief valve limits pressure in the raise circuit.



Is any of this information helpful?