Disc break pulled lever when wheel was off

[Malcolm Poteat]

Hi guys
I’m need of some help by making a stupid mistake.

I setup up my wahoo KICKR and forgot to stick the spacer in the disc brake and I’ve pressed the rear lever and my pads are now in the closed position. How do I rectify this?

Thanks guys

[ReapThaWhirlwind]

There's a tool for this called a piston press.

Alternatively, you might be able to use a screwdriver (or the like) to push the pistons back in.

[enkei]

Things to note if you have to push the pistons back:

1. it's worth cleaning the area around the pads and pistons (compressed air, oil-free rag, brush and/or water) to stop contaminants getting into the bore when you push the pistons back

2. don't push the pads too far back into the bore, you only need enough space to fit the brake disk

3. if you use a screwdriver to do this, be careful not to damage the pads (BTW, the correct tool for this job shouldn't be too expensive), or try using a plastic tire lever

4. if the brake feel is spongy after you're all done, it's possible the pistons over-extended when you inadvertently pulled the lever, and you'll need to bleed the hydraulic system.

Other than that, you should find it's not a major project.