Piston upside down?

[SpookDog]

I always thought that the piston was supposed to have the flat ‘head’ inside the calliper, so as to have the least amount of fluid in the calliper?

The person who had the bike before me had it so the face was pressing against the pad. Is this the right way round?

[markus.w]

I think it is the right way. The recessed part is inside the calipper.

[SpookDog]

Do you mean ] ]
Or [ ]
If that makes any sense?...

[markus.w]

Sorry yes I think it is right as it was. I just looked at the Haynes manual, the caliper exploded view and it shows the recess inside to sort of cup the fluid if you get me.

[Calum]

Pretty sure I have seen both types of piston used on different vehicles. Aprilia brakes the piston is inverted compared to my MX5 brakes.

[SpookDog]

It’s cool. I just took the front calliper apart and the ‘base of the cup’ goes into the calliper. It has a dust boot groove around the ‘lip of the cup’ so it can only fit one way up...
The back will be the same...

I thought it was wrong. Haynes manual doesn’t really help either, the line drawings are ambiguous, they should have a proper photo really...

[declan]

@SpookDog the cup should be facing the brake pad I've never seen flat side facing the pad although I don't doubt it exists the cup keeps little contact area so it's less likely for corrosion to glue the pad to the piston EDIT- emphasis on the "should"