  The $\eta \to 3\pi$ decays are a valuable source of information on low energy
QCD. Yet they were not used for an extraction of the three flavor chiral
symmetry breaking order parameters until now. We use a Bayesian approach in the
framework of resummed chiral perturbation theory to obtain constraints on the
quark condensate and pseudoscalar decay constant in the chiral limit. We
compare our results with recent CHPT and lattice QCD fits and find some
tension, as the $\eta \to 3\pi$ data seem to prefer a larger ratio of the
chiral order parameters. The results also disfavor a very large value of the
pseudoscalar decay constant in the chiral limit, which was found by some recent
works. In addition, we present results of a combined analysis including $\eta
\to 3\pi$ decays and $\pi\pi$ scattering and though the picture does not
changed appreciably, we find some tension between the data we use. We also try
to extract information on the mass difference of the light quarks, but the
uncertainties prove to be large.
