Drivetrain Axle movement after installing 5-lug conversion

A little in and out movement is normal. It should be about 1/16th of an inch or so. Maybe a hair more. C clips can wear over time and cause excessive play. You'll want to check and make sure the clips aren't close to falling out when you push the axle in. I've never seen that ever happen. Usually the axle is machined to hit the pin before the clips can pass the gear. The gears can also wear in the clip area but it would've been obvious by the condition of the clips. The axle would've worn an obvious wear spot.

Put the rum on with a lug nut to hold it on the axle. If it's not hitting the backing plate when pushed in you are ok. ( provided those c clips weren't worn to hell when you put them in ).

I wanted to add. The axle against the pins stops the inward movement. The c clips stop the outward movement. If you want to measure the shoe pad contact area you'll need a straight edge and measure from the face of the axle flange ( where lug studs are ) to the back edge of the shoe material. Now measure up from the mounting pad inside the drum and to the measurement you just got on the car. This will let you know where the shoe will ride inside the drum. It should stay inside the drum barrel. There's usually a small lip of drum that isn't contacted that would be closest to the backing plate when on the car. You want to take the on car measurement twice. One with the axle pulled out as far as it'll go....and one with the axle all the way in.

Hope this helps.