hi my y reg nissan has a front driver side brake problem when applying the brake there is a knocking sound,when wheel is removed the disc is free from the hub,the piston in the caliper is realy hard to force back have removed caliper and drained old fluid but still have same prob could it have anything to do with abs not working propley?
if your piston dust cover is split letting in dirt etc, may be starting to seize up,pull back cover and check there is no rust or pitting on the piston and check pads are nice and free in the bridge,if not get some copaslip and lube them up and make sure everything is nice and free,if no better maybe worthwhile going to a scrappy for a good 2nd hand caliper
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