Thanks peeps for the input on this issue, I am aware of the issues with the plunger just the one i am using was changed not so long ago when i re-new'd the chain, just think its a waste to bin the plunger as it is not that old, just wanted to know if you can re-set the piston. IANSOUTHAM if you know how or point me in the direction of resetting the plunger please point me in the right direrection if you can, the car is in bits and cant get hold of a new plunger as on back order .