mfwalker55,
The following is copied directly from the Mahindra manual Hydraulic section for the 30 series - 5530/6030/6530- this may be your issue. This knob is located directly below the front of the seat.
Isolating Valve
While carrying implement on a tractor for a longer distance
it is essential that the implement does not drop down
suddenly due to inadvertent movement of PC lever.
An Isolating Valve provided on the tractor serves this
purpose and can be used as follows,
1. Lift the implement to maximum height vide PC lever.
2. Loosen the locking bolt (E).
3. Turn the lockplate (F) outwards.
4. Turn the Knob (D) in clockwise direction fully.
5. Tighten the locking bolt (E).
The implement now cannot be lowered vide lowering the PC
Lever and hence can be transported safely for longer
distances.
For lowering the implement when desired,
1. Turn the Knob (D) in anticlockwise direction fully.
2. Turn the lockplate (F) inwards.
3. Tighten the Locking bolt (E).
4. Lower the implement vide PC lever.
Hope that helped.
idaho2