Lancaster used several ejector systoms ,if it is the one I am thinking of then it is not an easy one to repair . The spring serves a mulitple function and it is a case of being absolutly right .Almost will not work .I had one in some time back ,it was beyond me and I had great dificulty in getting some one to take on the job .Hope you have better luck ,But as said it wont come cheap and it wont be quick