Are you rebuilding the slave cyl? We use to rebuild them back in the day but have found installing a new assy is a lilttle bit more $$$ but saves you in the long run. Stupid question. I know you are putting the right brake fluid in ( DOT 3)
But I have seen drivers put anything ( Trans, engine oil......water ) they can find into the brake master cyl and spoil the brake fluid and screw up the rubber seals. you might have to flush the brake lines. Hope this helps.
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