I believe I'm in the right category of Minis. Have a 2012 Mini Cooper Countryman (base model) and am replacing the Water Pump's Pulley. I'm at the point now where I just need to position the new wheel and tighten the bolts, but the center hole on the wheel is ever so slightly off from the spindle of the water pump. I can put some downward force on the wheel and it comes so close to lining up enough to pop the spindle into the wheel's center hole, but not quite enough to actually do it.

Seems like the idler pulley could potentially be moved down/out of the way though just to get the wheel into place, but I don't have enough room to just take the whole idler pulley assembly off. We have a cherry picker holding the engine up and have lowered it a couple inches just enough to be able to take off and put in the new Water Pump Pulley. So although I have some access to the idler pulley's lower part, I can't really get to the upper part.

I'm curious if anyone knows if there is a way to separate or adjust the length of the idler pulley. I notice that it has a joint that moves just a little, and thought it might actually extend just a little bit so I could get the water pump wheel back on, but I don't see any obvious adjustments. I did notice this little plug/tab on the idler pulley though (circled in red in my picture). Does anyone know what that piece does on the idler assembly? Or have any suggestions on how to get this new water pump pulley to line up properly? I imagine the idler wheel and the water pump pulley need to be pressed pretty tightly against each other since there isn't a belt involved, but I didn't expect it to be this difficult to get back in place!