A FORMER liberal leader has made a rare public appearance, fuelling speculation that a few of the associates of ousted party chief Zhao Ziyang might make a comeback. Zhu Houze, a former head of the party's Propaganda Department and the All-China Federation of Trade Unions, took part yesterday in a conference on the relationship between the market economy and youth crime. The state-run China News Service last night said Mr Zhu, a leader of the party's liberal wing, participated in the symposium, which was hosted by the China Contemporary Society Research Centre. Mr Zhu was disciplined and forced to retire after the June 4 crackdown for failure to prevent staff of the trade unions from playing an active role in the 1989 pro-democracy movement. Chinese sources said Mr Zhu, also a former party boss of Guizhou province, had last year turned down offers of a couple of ministerial-level positions because he refused to admit his ''errors''. Analysts said the eclipse of hard-line leaders like Prime Minister Li Peng might pave the way for the gradual comeback of liberal leaders associated with Mr Zhao.