If the arms lower by themselves, is the problem the kit or the hydraulics?
If the arms lower slowly under load, the cause is almost always hydraulic: an internal leak in the cylinder seal or the control valve. Remove the kit or cut its supply and move the lever to the transport position by hand; if the lowering continues, it has nothing to do with the kit. The kit only has an indirect effect if the cable tension is not holding the lever in place.
Do the following in order:
- Disconnect the kit's supply cable and release the mechanism.
- Move the lever to the transport position by hand, raise the implement and wait 10–15 minutes.
- If the arms still lower, the problem is entirely hydraulic.
Hydraulic causes: internal leak in the cylinder seal, control valve wear, low or contaminated oil, blocked filter.
Indirect cause on the kit side: If the cable length was set wrongly during installation, the lever may not seat fully in the transport position. If the cable is looser than required, the kit cannot pull the lever far enough; if it is attached tighter than required, the lever hangs at an unstable point. The cable is not detached from its original end on the tractor side; only its outer end is connected to the kit's cable entry socket, and the length is adjusted there.
Safety: Never go under a hitch that lowers by itself. Lower the implement to the ground or put mechanical support in place; hydraulic pressure alone is not considered a safety device.
The full topic: Converting a tractor hydraulic lever to electronic control