Hi. Tried fitting new discs to the front this afternoon,I was there for a good hour trying to get it to fit bat it kept jamming on the calliper. Screwed the wheel locator right in and the disc had considerable movement. took it off and put the old one backfirst time nice and snug with no movement.Callipers are bosch.and discs are Bendix 257mm.Are they compatible? Have tried repeatedly but they will not go on, they seem too big? they are 257mm and the old ones seem to be 255mm. Regards Alan.