I’m having trouble

I don't have any 420s , pretty sure they are all made the same , on my 450s an 300s only one side has a retainer ring , so it only comes apart on one side ----- I don't know why you are taking it a apart , maybe change a boot , clean it out and regrease , but any ways , I have found it easier and better to just get a new axle , they are cheap enough now days , I have been using Sixity axles , they come in two qualities , I have been buying the better ones , have never broke one yet and have about 3 years on the first 450 axles I bought , and I ride a lot in nasty stuff