[Excaliber]

It's not that the spacer flattens out, gets thinner, it's just normal wear and seating of the bearings and races in the hub. The spacer in question here is how the wheel bearings are adjusted. On the front you can turn the wheel bearing hub nut tighter or looser. No such nut on the back, so adjust bearing clearance by adding or subtracting the shim thickness.

.002 or "0" clearance is the spec. Very common on almost all Jaguars for the bearings to be a much looser fit than this. Think of it as having a loose front wheel bearing, not good if it's to loose but better loose than tight. With plenty grease it will run a long long time on the loose side. A somewhat "loose" bearing adjustment in the hub is not a big factor in the failure of the stub axle, hub assembly, etc., just my opinion. What IS "to loose" could be debated for some time.

Of course you can't go wrong saying a guy MUST be within specs, .002 or zero end play float. It's really not that big of a deal installing a new shim and they are readily available from Jaguar in various sizes.

I would be far more concerned with the possibilty that the race(s) don't fit "snugly" in the hub housing. If the races are "loose" they could "turn", this will ruin the housing in short order and could lead to big failure. If the races don't fit snugly (tight) the shim adjustment will not hold for long. If your having them proffessionally checked, check that race press fit first!

Former Jag mechanic.