[A8] Bolt size holding on front (Lucas) calipers?

[Rich, Jack]

I went to replace my front rotors and found that the bolt holding on the caliper was larger than my largest size of 19mm. I've never encountered this problem doing brakes before. Does anyone know what size bolt this is? This is a 2001 A8L with the Lucas calipers (with the dual piston, 4 pads per caliper.) 

Thanks,

Jack Rich
Senior Member of Technical Staff
Kronos
www.kronos.com
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