2006 Cooper S. I'm replacing all pads and rotors (first time brake replacement for me and the car). When re-installing the rear calipers, I've noticed a gap between the dogbone and the caliper. In other words, when you have the dogbone bolted onto the caliper, you can see the lower allen bolt thread where it passes through to screw into the caliper. This is noticeable on the rears.

I first noticed this on the driver side rear. It looked like something was amiss, so I disassembled and re-assembled and the gap remains. It also feels like the bolt is bottomed out. I'm not understanding this as the bolt thread did not appear to be exposed to any elements that would normally give it a rusty/corroded look after removal. It was as shiny as new.

Something doesn't look right. Now when I moved over to the passenger side to remove the caliper, I checked to see if that gap was present. It was, but I didn't see the threads. It almost looked like you could see the upper shaft of the bolt...not the threads. As I pulled the bolt out, I tried to pay attention to see if a spacer or something would fall out. Nothing did and when I pulled the bolt out, it had the same new shiny appearance. I'm guessing that the rubber boot inside the hole wiped it clean. I just can't understand why the drivers side is showing threads after re-installation and it feels bottomed out when tight.

I don't think the upper and lower are 2 different lengths are they?

 

Ok....I'm not seeing threads of the bolt. I'm seeing the bolt shaft. It looked like threads last night in poorly lit area. But the gap is still in question.

 

it is fine. i had the same question the first time i changed rear pads. i've now done it about 40 times and it still doesn't look quite right.