The bolts holding the wheel cylinder on should be bigger than 1/4". I believe they are 10mm. Try that size. On the other hand, if you are referring to the bleeder, it may be the 1/4".
Do me a favor. I attached the directions below specific to this vehicle for the replacement of the wheel cylinder. The number 1 bolt is the bleeder and number 2 is the mounting bolts. Let me know if that is what you are referring to.
Take care and let me know if you have questions or what I can do to help.
See pics below.
Images (Click to enlarge)
Sunday, September 25th, 2022 AT 8:14 PM