Most likely a 15mm wrench. Unlikely to be Allen in that vehicle.
3/8 Allen wrench
It's 12 mm bolts, not Allen key.
That is a 3/8 Allen.
3/8 in.
You need a 3/8" Allen wrench to remove them.
Grab an adjustible wrench and turn it (Left). It should come right off.
Allen wrenches come in various sizes. There is no definitive information as to what size is needed to remove a brake caliber so you will need to match the wrench size to the best of your ability.
I believe that's a 5/16 or maybe 3/8 Allen.
Get an Allen wrench and take off the plastic cover on the top of the motor and they are all under there..
The part store that I went to did not have a specific tool to use so I purchased a 10 mm Allen wrench and had to go back to get an 8 mm wrench and it did not fit.
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