706 Hydraulic Problems

I just had the reverse drive gear replaced on my 706 Farmall and I bled the system got the steering to work and torque but after it worms up the TA quits and tractor acts like its not going very fast. I added more hydraulic fluid and now it's coming out under my steering wheel did I add to much or is my seals in it bad?

Seal on steering 'motor' is out.As for loss of pressure when hot,I'll bet the MCV pump is shot.You really cant add "too much" oil to those.

Sidenote...TheMCV pump/valve serves 4 funtions.3 gpm each to steeing,brakes,TA lockup,the remaindre going as lubrication of rearend gears.Low pressure lets the TA slip,thus ruining the TA.Do NOT run tractor till pump is replaced.You can run some pressure tests to comfinm.Hook a 500(?) lbb gauge to the 'bleed' port and observe

(quoted from post at 10:52:26 04/01/14) Sidenote...TheMCV pump/valve serves 4 funtions.3 gpm each to steeing,brakes,TA lockup,the remaindre going as lubrication of rearend gears.Low pressure lets the TA slip,thus ruining the TA.Do NOT run tractor till pump is replaced.You can run some pressure tests to comfinm.Hook a 500(?) lbb gauge to the 'bleed' port and observe

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The 9 gpm (at rated engine speed) MCV pump flow goes first to a priority flow valve with a 3 gpm orifice. The 3 gpm flow that passes through the orifice goes to the steering. The rest of the flow goes to the oil cooler in front of the radiator and then back to the MCV where it is sent to the rear frame to lube the reverse idler shaft assembly and then on to lube the ring and pinion gear and the range transmission main shaft.

The 3 gpm flow that goes to the steering returns to the MCV where the pressure regulator valve maintains the pressure at about 240 - 270 psi for the brakes and TA. If the steering is put on high pressure from load there is a steering relief valve that limits the pressure to 1600 - 2100 psi depending upon the tractor model. Oil that bypasses the relief valve is ported to the steering return flow in the MCV.

Once the oil passes the pressure regulator valve on a 706 or 806 1gpm flows to the brakes through an orifice in the brake control valve (open center) inlet fitting leaving 2 gpm for TA control. On tractors newer than the 706 and 806 the brake control valve is a closed center valve so there is 3 gpm flow available to the TA except when the brakes are being applied. The oil flow remains after leakage from the brakes and TA goes to lube the TA where it is limited to about 18 - 20 psi.