Delta Single Bath Faucet leak

Hi, My Delta Single Bath Faucet is leaking under the handle. Here is a link that shows it: Troubleshooting a Leaking Faucet : Delta Faucet (http://www.deltafaucet.com/customersupport/troubleshoot/bath-single-handle.html) This seems easy as I have repaired it before. But this time it is not working. I replaced the ball and cam with known working ones but not brand new and it is still leaking. I have tightened the cap and it is still leaking.