It is stamped on the edge, but good luck finding it now!

Actual spec is, I think, 0.42". this is AFTER they are turned, if you were thinking of doing so, and minumum thickness at any point, not average or largest.

Two quick and dirty ways to tell -- How many sets of pads on this set of rotors? MB recommends new rotors every third pad change.

Is there a visible/palpable lip at the outer edge, and is the inner edge worn down to the level of the hub? If so, replace, they are too thin. Not much meat on these things, keeps unsprung weight down.

Also, how close were the backing plates on the old pads to the anti-rattle spring? If it looks as though they would touch the spring before the lining was gone (especially if they would touch before the slot was worn off), or they DID touch, get new rotors, the old ones are too thin.

Don't take a chance on underthickness rotors -- they will cause the pistons to lock up in the bores after the new pads wear down, hit the spring and cock. Doesn't stop worth diddly then, either (and it's costing me $250 in parts on the 280 right now!)

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!