TO30 Hydraulics Question

The system pressure should be 2050PSI.

To check the pressure properly you need a pressure gauge coupled to either a trailer pipe connection or into one of the tapping points on either the lift cover or Hydraulic Pump assy. The linkage arms need to be held from going to the top of the lift stroke, by either using a trailer Pick-up Tee bar (ideal) or some strong stay bars used with the drawbar (standard ones are NOT strong enough) and they should NOT be coupled to the top link connection on the tractor. When you have all this in place, move the fingertip control lever to the lift position and check the reading on the gauge, should the reading be low. (i.e. by more than 200psi) then you can assume that there is a leak in the system and that it isn’t just the relief valve (also called safety valve) blowing off or even leaking due to wear. At this point I will warn you DO NOT PUT YOUR HANDS INTO THE HOUSING WHEN THE ENGINE IS RUNNING
Check the main control spring, (under the seat) for end play, there should be no end play at all but you should be able to turn it with an implement mounted and in the raised position, if there is any end play this will have to be removed, as this alters the control valve linkage internally. The Hydraulic lever quadrant should also be checked that it is set correctly, again with the implement raised, move the lever slowly forward till the implement starts to drop, then move the lever slowly rearwards till the implement neither lifts nor lowers, at this point the front of the lever should be 2 ¼” on TE20 or 2 ½” on TO20/30, to adjust this setting, slacken the 4 bolts that secure the lever to the lift cover and move the quadrant slightly till you get it right. Make sure that the control spring is set correctly first though otherwise you will only make matters worse by trying to set the quadrant first.

Remove one or both of the round inspection covers on the centre axle housing which contains the hydraulic system, Run the engine with the PTO and Hydraulic Pump in gear, with either the rear linkage fastened down as previously or with an implement mounted in the normal way, lift the rear linkage and look inside the inspection cover using some light so you can see inside the top of the housing, you will see the hydraulic lift ram cylinder right above the inspection holes, there should be little or no leakage from the rear end of this. If leakage is occurring, it can be a damaged piston or worn piston rings, the leakage rate should not be a constant flow, but drips are ok. If there is no leakage from the rear of the ram cylinder, now check the front of the cylinder, if there is a leak here it can be either a cracked cylinder or possibly just the gaskets under the cylinder. If this is the case the Hydraulic lift cover will need to be removed to replace the gaskets (see separate sheet for instruction on this) If there are no leaks in the top around the ram cylinder then check the front right hand corner of the lift cover inside the housing to see if there are any leaks in this area (this is where the pressure from the pump is fed into the lift cover) it is possible that it could have blown the main gasket under the lift cover due to the bolts being incorrectly tightened or not being checked for tightness occasionally. (From TE20 serial number 330,043 (1953) the hydraulic relief valve was moved to this position, you can check this externally by looking if it has a large square bolt head at this point or the original small plug with the recessed hole for an Allen key). If there are no leaks in the top at all then the leak must be in the bottom of the housing in the area of the Hydraulic pump

With the linkage still in the raised position and with the engine running, check in the bottom. Of the housing for the oil swirling around (there will be movement of the oil because the pump is running but that will only be slight) check for the swirling of the oil and that is where the leak is occurring. If it is at the front right hand side it could be simply be that the gasket under the pump has blow at the point where the pressure leaves the pump to go to the lift cover, again this is usually due to the bolts not being sufficiently tight.
(To remove the hydraulic pump, see the separate sheet)
If the swirling is towards the rear of the housing and maybe only on one side then it could be a side chamber gasket leaking, but usually you will find that the hydraulics lift in a jerking fashion (due to pressure from one or more cylinders not being available due to the leak) If this is the case, you will have to remove the hydraulic pump to effect a repair.