We may have found other answers which could help you.
Click here for Flush Wall CisternGrohedal flushing?
Toilet Push Button not flushing properly?
GroheEAU2 Dual flush cistern. The large flush button keeps breaking off?
Grohe push button toilet attached to saniflow ?
How do I remove the fitting for the flush on my hidden cistern toilet?
how do I change the bellows in the push button unit for the grohe cistern?