gerrythom

I have just replaced my rear brake pads and cleaned the corrosion from the back of the caliper and the suspension arm. The caliper split into the two halves. I have put everything together again and when trying to bleed the system the brake fluid is escaping from the top end of the caliper. Should there be a rubber ring seal between the small holes on the top part of the caliper where the two halves meet? I think I may have lost it when dismantling the caliper.