When I bought my 1993 LX I received an LMR 5 lug conversion kit with it. It was the 31 spline version (LRS-4234B-K) using Yukon axles. My car has 28 spline spider gears still so I bought the 28 spline Yukon axles (YA-F750004K). I used the stock c-clip that were already on the car when installing the new axles. With everything installed, there is a small amount of play. I used the drums from the 31 spline kit so I'm not sure if they are different than what is offered with the 28 spline kit but I cannot imagine this is the case. Are there other c-clips that need to be used? I cannot tell what is causing this movement. Possible that drums are not fitting correctly but I cannot tell. Please help! I can provide more info/part numbers if that helps.
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.