I agree with Tom, try to stay with the original. Our lock cylinder is a little touchy, have to fiddle with the key some to get it locked. I found that to be able to use the inside lock button, the lock cylinder has to be centered, that is when you unlock the door by turning the key clockwise, then turn it back halfway. Some parts are available on eBay, and rebuild kits are available there. The whole assembly is easy to remove. I cleaned up mine and lubricated it with white grease. I bought a whole new in the box latch assembly on eBay for $60 (deal of the century) and a used one for about the same price.