turbo bob1.8

Hi folks, I'm new here, hope you can help with this little problem.I've got 1.8 tdci focus euro 4 (electronic type) egr setup. I was going to blank this off after reading about the benefits, so started job by unbolting the small bent corrigated elbow pipe from exhaust manifold then undid the clamp that joins this pipe to the egr cooler, however at this point I lost all confidence in what I was doing and decided to just put it back together and go and watch tv instead
After putting small pipe back into position and putting clamp back over the join and re tightening and re bolting to manifold,I'm now getting fumes in the car that must be leaking from the clamp.( soot around clamp and on pipe). Its tighter than it was before I removed it as more thread is showing,but its still blowing. When i removed it I simply bent it open and when I replaced it I just pinched it together and tightened the bolt, could I have damaged clip? Also was there some kind of sealing ring/ washer between the flange where the pipe joins the cooler that I may have dropped from the assembly when I dismantled it ? ...couldn't see anything after I re assembled. Anyone with any answers ,experience or solutions please re-ply,cheers