Hello looking for this Allen head bolt seems to be M18. Anyone know if this bolt is available or similar Toyota or lexus model share same part. Sorry I don't know the name of the part.

 

From my searching through lexus parts catalogs', It doesn't appear they sell this bolt separately at least in this application. I would pull one out and go to the hardware store to replicate it. Also OEM lexus appears to be using a torx bolt; whereas yours are allen so it looks like they've already been replaced before.

 

Yes that seems to be the case. I did see that mine are allen heads. managed to find them there called a socket cap screw high tensile. M12 X 400mm. May be should of got the the torx.