Remember the GM "Torx" fasteners that started in the early 80s?
I was stumped the 1st time I did brakes on my 1st Dakota an 98 R/T 2wd hot rod
couldn't figure out what size (I thought) the allene head bolt was on calipers
to change the pads when doing an upgrade,
my 1997-99 Haynes service manual was of no help on size or style (bolt head)
I tried every allene wrench & socket, up-to 3/8" allene & metric up-to 10mm, that I had
I thought it must be a huge one, none would grab at all, even remotely
So I too a break, went to Harbor Freight & I bought some cheap sets of bigger
allene wrenches & male sockets
No 6pt or 12 pt sockets would fit either, & the access how thru the rubber deal
was sort of small to be of any real size 6pt/12pt bolt head
In my defense of stupidity, it is/was under a rubber seal deal, to keep grime out
can't/couldn't easily see where I was working, to see in it
by chance I tried a Torx socket & turns out it has a Torx head, like 3/8",
I had in my box already...
I'll never use any of them bigger ones, 'ever', so I took them back not trouble
not just GM BS, ma MoPar too