Premature Injector D-Ring Failure

What causes premature D-ring failure on Ford diesel injectors, and what are recommendations to resolve the issue?

Premature D-ring failure of Ford diesel injectors is usually caused by either a leaking ball tube O-ring or leakage between the ball tube and injector D-ring. In the case of a leaking ball tube O-ring, ball tube O-rings flatten and harden with age, allowing pressurized oil to escape past the ball tube O-ring – blasting the top of the injector D-ring. Installation damage to the injector D-ring from the ball tubes being misaligned can cause leakage between the ball tube and the injector D-ring.

To resolve the issue, replace ball tubes and O-rings when installing injectors, ensure the ball tubes are properly aligned during injector installation, and use clean engine oil to lubricate the ball tubes prior to installation.