how can fix my 306 hdi meridan?

The diesel leak on your injector could lower the rail pressure to the point where the vehicle will not start., so the injector leak will need to be fixed/injector replaced as an initial repair. If you are able to read DTCs then this would confirm whether you have a code for low fuel pressure, I would recommend doing this as an initial diagnostic procedure, get your local dealer or specialist to do this before undertaking any repair yourself. I also believe that Peugeot recommend replacement of any pipework once it has been removed once, to prevent future leaks.
IMPORTANT- Under no circumstances should you slacken injector pipes or remove injectors and crank the engine, this common rail system can generate rail pressures in excess of 1000 bar, fuel at this pressure may cause serious injury if it makes contact with the skin.

Gary
March 2007