So I was changing the brake pads on a friends 08 g37 coupe, and I assumed it was similar to my Toyota where you just pop off the caliper housing and replace the pads, so I took off the 4 bolts on the back of the housing, and half of the caliper, as seen in the picture came off, and brake fluid started coming out. Realized my mistake, put it back and tightened the bolts back on. Figured out how to replace the brake pads correctly, but now the brake pedal is soft and kinda unresponsive unless you really step on it. Is it air in the brake system and requires a brake flush?

 

You should be fine just bleeding the caliper. Remember, the sport brakes on THESE cars have two (2) bleeder valves: inner and outer. Bleed the inner one first, then the outer.

However, as you essentially partially disassembled the caliper, you will have to make sure there is no leakage where the two halves come together.

I would only flush the entire brake system if the existing fluid is old or of questionable quality. Only your friend knows his/her maintenance history.

Toyota... good grief man...

 

So I only partially disassembled one of the calipers, I did it correctly on the other one. I only have to bleed the one I partially disassembled and don’t gotta worry about the other one?

 

You should be able to just bleed the caliper you disassembled. Once bled, go from there.