Q7 rear caliper pistons

[theonlyhamish]

Hi folks I’ve never changed brake pads and discs on an Audi.  My brake pad light came on and after a quick look I could see the drivers rear pad was worn.

wheel off etc to realise there was some binding happening by as the outer pad was down to nothing.

I can see now the pads are remove that all 4 pistons, the dust boot appears to have become unseated from the caliper which leads to this stupid question because I’ve never seen it in my life where all 4 pistons would suffer the same fate.

is there meant to be a bare metal piston between the dust boot and caliper seal?

Edited February 21, 2023 by theonlyhamish
Added image

[Stevey Y]

2 hours ago, theonlyhamish said:

Hi folks I’ve never changed brake pads and discs on an Audi.  My brake pad light came on and after a quick look I could see the drivers rear pad was worn.

wheel off etc to realise there was some binding happening by as the outer pad was down to nothing.

I can see now the pads are remove that all 4 pistons, the dust boot appears to have become unseated from the caliper which leads to this stupid question because I’ve never seen it in my life where all 4 pistons would suffer the same fate.

is there meant to be a bare metal piston between the dust boot and caliper seal?

Hi no, this is what happens when the pads are allowed to go to the bottom limit the rubber boot won't stretch any further and the piston pops out, in the picture it does look very corroded so I would suggest buying new callipers as your ones are most likely seized and won't do the seals inside the calliper any favours, exchange units are fairly cheap.

Steve.

[Stevey Y]

Just now, Stevey Y said:

Hi no, this is what happens when the pads are allowed to go to the bottom limit the rubber boot won't stretch any further and the piston pops out, in the picture it does look very corroded so I would suggest buying new callipers as your ones are most likely seized and won't do the seals inside the calliper any favours, exchange units are fairly cheap.

Steve.

PS when you took the pads out was the rear braking system in service mode?

[jdragon]

Big red are awesome for piston kits and exchange callipers.

[theonlyhamish]

Not sure about the system being in service mode, wasn’t aware of that, the cars air suspension system was in wheel change mode but I never changed any other settings.

just find it really strange that all 4 pistons are like this, only the outer pad was worn to nothing, the inner pad was fine.

 

[theonlyhamish]

14 hours ago, Stevey Y said:

PS when you took the pads out was the rear braking system in service mode?

I’m assuming this is for the electronic parking brake?  My model has the manual parking brake.

[Stevey Y]

9 hours ago, theonlyhamish said:

I’m assuming this is for the electronic parking brake?  My model has the manual parking brake.

Hi happy days the callipers are even cheaper for the manual hand brake.

Steve.