i busted a bolt holding my ca;iber on on my1993 dodge dakota i bought new bolts but cant find the right tap are they a special size i drilla it and taped it with a metric 10 mm1.50 but it stripped right out how can i fix it now maybe a helo coil but i need to know what size the thead is

 

I had the same thing happen to me on my 94. The size is a 9mm by 1.25 pitch. This is a rare size, and I had to do a bit of looking to find the Helicoil set. I finally found it at Oreilly auto parts for $42.00. Then I had to find a size D drill bit.Again, more searching and ordering. Whatever you do, don't use one of the HELP brand caliper studs. They will cut new threads in the spindle that will leave you with too large of hole if you ever wind up here again.