You'll have to disconnect the return lines from each injector when you replace it. When you re-use the return lines there is every possibility that there will be a leak. If the lines are old they will have hardened a bit, and be more difficult to reseal. OTOH, they are easy enough to replace if they do leak. It's just time and effort and frustration. If/when you do replace the return lines be sure to cut them to the proper length. There should be NO curve between injectors down either side. A curve in those short spaces puts undue lateral pressure on the injector nipples where the lines connect, making them harder to seal. They seal much better if the line goes on absolutely straight. The longer lines will have curve by definition.
Before you pull an injector you might want to vacuum around the area, and wipe it down, and vacuum again. I suggest you do the vacuuming when your wife isn't home. She may object to your using her vacuum of your greasy engine.
Yeah I know what you mean by the curve in the hose.
I replaced mine several years ago, and bought rubber hose from O`Reilly`s, and it does have a curve when you cut the short pieces, and it s stiffer. trick is to alternate the curves, and it will go on straight. it never caused any leaks. The cloth hose doesn`t seem to have the problem.
Another trick is to connect all 4 cap together, then drop the assembly on and click the caps down. Be sure to grease them up good.
When you put the "O" Rings on, use some grease and slide the first one on the top groove. Then slide the second one over the top one to the lower groove.
If for some reason several months down the road you mess around and move one of the caps and it starts to leak. Changing the "O" Ring on the leaker, you will move the next one and so on, and more leakers. Just pull the whole side off, and replace the whole row of rings.
Not a big deal, just a P I T A thing that happens.
You can buy the rings off Amazon or McMaster-Carr. 50 for around $10 a bag, size 111.
Goat