A wire tieing system for wrapping and tieing a bale of material with wire comprises a wire guide for guiding a wire around a bale of material and a tieing head configured for receiving portions of a wire in the guide and securing the portions together to thereby tie the wire and therefore tie a bale of material. The tieing head is pivotable with respect to the wire guide and is operable for being pivoted between an operating position proximate the guide and a maintenance position away form the guide. A head pivot assembly maintains the tieing head in the maintenance position. The head pivot assembly comprises a support block and a locating pin which are operably movable to engage a portion of the tieing head when the tieing head is pivoted to the maintenance position to prevent the head from pivoting back to the operating position.