[MatthewH]

Hi,

I'm currently in the middle of changing the rear discs and pads on my A8. Passenger side has been completed successfully.

Unfortunately, the driver side has a seized piston (the piston boot was torn) and won't wind back. The pads were also stuck in the shims and caused the disc to wear down. I'm hoping this is the cause of my low MPG issues as I've mentioned in my other thread. I have purchased a new (used) caliper and will replace it when it arrives in a couple of days.

One thing I noticed when doing this job was the offside and nearside pistons seem to be different designs. One side has 3 "cut-outs" for a piston rewind tool, but the other side doesn't. See the photos attached.

Is this normal or has someone replaced one of my calipers with the wrong part at some point? Do the pistons need turning or should they just push back? I know VCDS unwinds the electronic handbrake but they still need pushing back a little bit to give room for the new pads. As one caliper has the "cut-outs" it suggests they need turning, but there is nothing to grip on the other side.

The side I have already completed has the cut-outs and I wound it back using a rewind tool, but this may not have been necessary if they just push back.

Thanks