It its had dot4 or dot5 instead of the VG10 thats supposed to be used then yes, you could well have ruined seals in the master cylinder and also possibly the axle pistons. Common mistake for non-Crown techs to make or when 'the local mechanic does my servicing'...it usually ends in a costly bill with the latter. Oil cooled disc brakes are non-adjustable so you can rule that out.