How do you replace a leaking injector cup?
Replacement requires precision:

Disassemble: Remove injectors and clean the bore.

Extract old cup: Use a specialized puller tool.

Install new cup: Press-fit with sealant (e.g., Loctite 62, then machine or ream for perfect alignment.

Pressure-test for leaks before reassembly.
Tip: Always replace O-rings and inspect injectors for damage.
https://www.cq-longshine.com/cummins-injector-cup