Results obtained by neutron diffraction indicate that the magnetic moment of the ferromagnetic sublattice in the Laves phase structures, C15 (ErCo2, ErAl2) and C14 (ErCoAl), varies with composition while the ordering temperatures stay approximately constant. Low values of the aligned moment, however, are accompanied by high values of the disorder scattering at low temperatures. Co carries no moment from 30 mole % ErAl2on. Results are discussed in terms of tendencies toward antiferromagnetism at certain values for the valence electron concentration.