i think its the pins siezing rather than the pistons,when car was mot'd it was picked up on uneven pressures,20% less pressure on the affected caliper at rear,front calipers dont seem to be affected.the difference is noticible as the car rolls on after breaking heavily now its been fixed. the car isa 2007,is220d se,[steve] you should be ok, i got leaking rear shocker to deal with now,which was not picked up on service but spotted when caliper changed yesterday, the dogs may bark but caravan rolls on eh!!!! lex loofah!