Hi there, peugeot expert 2004 1.9 D van problem. Changing clutch master cylinder (which only seem to last a couple of years). Am getting a leak with the new master cylinder at the coupling between the base of the master cylinder and the plastic hydraulic coupling coming through the firewall. All parts present and sparkly clean, including the little rubber grommet the fits over the end of hydraulic line. Have noticed however that the plastic coupler mounted on the clutch hydraulic line can be rotated.... Is it meant to be able to do this and could this be the cause of the leak? would have expected the plastic coupler to be heat sealed or similar on to the hydraulic line itself. Any ideas on the simplest fix for this please?