So if you come across the same problem with the fuel tank/pump metal locking ring not fitting flush or some metal slots are overlapping/misaligned then just use the original Green rubber O ring instead of the new one or get one similar in size to the OEM Green Rubber O ring. I came across the same problem with the new black Rubber O ring not fitting but used the original Green rubber O ring which is bigger than the new Black Rubber O ring in size and I was able to insert the metal locking ring back with no problems. (Took me 2 hours of struggling and finally comparing both Rubber O rings to release my mistake).
So if you come across the same problem with the fuel tank/pump metal locking ring not fitting flush or some metal slots are overlapping/misaligned then just use the original Green rubber O ring instead of the new one or get one similar in size to the OEM Green Rubber O ring. I came across the same problem with the new black Rubber O ring not fitting but used the original Green rubber O ring which is bigger than the new Black Rubber O ring in size and I was able to insert the metal locking ring back with no problems. (Took me 2 hours of struggling and finally comparing both Rubber O rings to release my mistake).
lovely stuff