The copper washer is the sealing sealing surface between the pintle (tip) end of the injector and the head. The return components are 2 O-Rings on the injector, the plastic cap and the rubber hoses.....
To replace the return lines:
1. Loosen injector hard line nuts and gently move the lines.
2. Remove the plastic caps and rubber lines. These can be used as a template for the new ones.
3. Remove old O-Rings from the injectors, remember there are two.
4. Replace the O-Rings, put the first one on, and roll it into the top O-Ring groove and leave it. Then roll the second one over the top of the first one. It will stretch and then roll to the second groove. This makes damaging the O-Rings less likely.
5. Generously lube the O-Rings.... many have used different things, I would recommend proper O-Ring lube.
6. Inspect the inside of the replacement caps for casting flash. A burr of plastic inside the cap is one of the biggest causes of cut O-Rings
6. I would cut and install the rubber lines onto the caps, make sure the length is just right. You don't want the hose to pull or push on the caps, this can cause a leak.
7. Install caps on the injectors. There should be a definite pop as they seat. An aid in getting them to seat, use a deep socket that is about the same size as the top of the cap, and give them a thump with the heel of your hand.......
8. HAND THREAD AND TIGHTEN the nut as much as possible. They will easily cross thread, and the line nuts are harder than the injectors and will damage the thread on the injector.
Once everything is done, fire it up and check for leaks...... enjoy your easy starts......