SMTA hydraulic setup

Brady Miller · Apr 29, 2014

Gents,

I am reconfiguring my SMTA with a 2 spool 2 position hydraulic valve system. The factory setting on the bypass is set at 2000 psi. What is a good rule of thumb to set the pressure at for my SMTA with a live hydraulic pump?

I have a Farmall M and I put a live hydraulic pump and a similar new valve system on it and I did not adjust the pressure. One day I ran it and held down on the lever too long and I figured I broke the moon key in the cam gear or the cam itself and I have not had time to repair it. I would like to get this one right.

Any suggestions would be appreciated.

Janicholson · Apr 29, 2014

The setting from Farmall was never 2000.
1200psi was normal, 1400 might be OK, but they were not made to be twisted quite that hard. Jim

the tractor vet · Apr 29, 2014

1250 is what a good system will do and trying to push more you will most likely lean all about cam gear failure . You will be like the one guy around here that did away with the Hyd. unit under the fuel tank and made up a tank for the oil and ran everything from the pump to his valve set up . First time he use it when he went to lift the disc at the head land to turn he did not let off the handle of the valve fast enough and deadheaded the cylinder and before the relief valve opened to dump the pressure off his tractor just stopped dead. It would not restart and i get this call about his tractor died . So road call and start looking at his reenginering and had to look no further then the rotor , when you tried starting the tractor the rotor did not turn anymore . So a new set of cam gears and it was back running and i reset the regulator to 1250 and it was fine . On the OLD systems if what your trying to lift won't lift get a bigger cylinder or get a newer tractor with higher pressure hyd.

sflem849 · Apr 30, 2014

Where is the factory pressure relief valve?

I do believe that is a 3 position valve. :wink:

D Slater · Apr 30, 2014

SMTA pressure relief is in the reservoir housing. Maximum pressure supposed to not exceed 1200 PSI on those.
That's why when IH added a remote control valve without a built in relief they teed the pressure line from the pump into the valve and on into the hydraulic unit. Also why the lever has a little latch on the side of the reservoir. Lever was latched back to keep the oil from circulating through the unit and back to the pump so pump pressure went to the remote control valve. Set up like that the factory relief valve worked for the control valve also.
Original poster could plumb the valve to use the same pressure relief if needed.

SMTA hydraulic setup

Brady Miller

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Janicholson

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the tractor vet

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sflem849

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D Slater

Well-known Member

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