Front brake rotor too large?

[Boiler Ben]

I am installing the front brakes on my MK4 now. These are the standard FFR ones. First had to compress the pistons to get the pads to fit over the rotor. But now I can’t get the bolts lined up on the spindle. When it’s as close as I can get it to being lined up, the rotor is touching the caliper. I took the rotor off and confirmed the caliper does bolt up to the spindle when there is no rotor mounted. But it’s almost as if the rotor ID is too large. Just measured with a ruler and it’s 11 5/8”.

Am I missing something obvious?

[michael everson]

Are you using the back rotors instead of the fronts? If you have IRS the back rotors are the larger ones.
Mike

[Jeff Kleiner]

Are you using the back rotors instead of the fronts? If you have IRS the back rotors are the larger ones.
Mike

Mike is correct that the standard IRS rotors are 13” and the standard fronts are 12” however if you optioned the 11.65” rear brakes for the IRS those would measure approximately 11 5/8”.

Jeff

[michael everson]

Actually the standard fronts are 10.8 or 276 MM

Mike

[Boiler Ben]

Shoot, I need to check the rears. I ordered the 13” IRS rear brakes so I assumed they must be larger but I’ll check. If 10.8” is correct for the front that would make sense with what I am seeing but would mean I have either 2 or 4 wrong rotors.

[Boiler Ben]

OK, my rear rotors are 13” which makes sense based on what I ordered. So I think that means FFR sent 11.65” fronts when they should have sent 10.87” fronts. Does that sound right?

[michael everson]

They don't make any other size fronts so they probably sent rear 11.65 rotors instead of the fronts.
If you dont want to wait for FFR just go to the parts store and get some front rotors for a 99 Mustang
Mike