42 Pa.C.S. § 8324: Right of contribution.

(a) General rule.--The right of contribution exists among joint tort-feasors.

(b) Payment required.--A joint tort-feasor is not entitled to a money judgment for contribution until he has by payment discharged the common liability or has paid more than his pro rata share thereof.

(c) Effect of settlement.--A joint tort-feasor who enters into a settlement with the injured person is not entitled to recover contribution from another joint tort-feasor whose liability to the injured person is not extinguished by the settlement.