I have got a BT reach truck with 8500mm mast with full free lift. The mast free lift doesn't work as it should before the carriage reaches it maximum the second stage starts to lift. The fault is worse with a load on. The carriage bearings have been changed and the carraige runs very smooth. The lift cylinder has been stripped checked and resealed and the flow control valve in the cylinder has also been changed. Any help would be appriciated.