Since you've been driving. The grease (assume you greased the axle bearing and bushing) will be settled. So simple pull grease cap off while tire on ground or jack under lower control arm. This keeps FDS (AKA CV) axle from being pulled inward. Then thread a 8 x1.25mm bolt into end of axle and pull on it. This is all just to make sure axle is pulled out as far as possible, while checking gap. Then place a feeler gauge between hub flange and snap ring. Spec is less than 0.20mm gap. If at or over, go up to next thicker size snap ring that yeild less than 0.20mm gap.
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As you can see this gap is way over 0.20mm at 0.56mm. Here we'd go up 2 sizes adding 0.40mm to thickness of current snap ring. The end result would be a gap on 0.16mm. Which 0.16mm would be a gap wider than I like to see, but within spec. I would try to get 3rd size up into grove first, as I pulled out axle as hard as I reasonable can.
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I keep bags of new snap rings of various sizes. I start at 2.8mm thickness and work down until I get one that fits in the groove. I use the 2.4mm (90520-31007) the "D" most often and 2.6mm (90520-31006) the "C" second most.
Note: if you use the 2.0mm or 1.80mm snap ring, I'll bet your gap is to wide. I'll bet you've not pulled the axle hard enough or settled the grease. Never, not even when replacing bearings, races, brass bushing, FDS and hubs with all new OEM parts, do use those thin snap rings used.
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Most often I'm setting snap ring gap after a full wheel bearing and knuckle service. Where I have greased the axle bearing & bushing (PM is every 30K miles) and installed a new seal.
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Or I've used my Slee greasing tool to grease the axle needle bearing and brass bushing.
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In these it's important to settle the grease between the FDS outer axle on brass bushing in back of knuckle. Here's old video of tools found in the shop to make a puller. I and other have made various tools for pull axle to settle grease and set snap ring.