I've just changed the silencer box on my 1.8 8V Renault Laguna. While I was under there I renewed the front pipe to intermediate pipe clamping ring, which is a U-shaped ring with a bar that compresses the front pipe onto the intermediate pipe inside it. A liquid more viscous than water(sulphuric acid?) used to drip from this joint after short runs. Is it possible that by 'fixing' this joint I may be retaining water, or worse, in the exhaust, thereby accelerating corrosion? Should I drill a small hole to allow it to drain away?
Also, I noticed that the box won't hang in the correct position by itself, and I needed to get someone to hold it while I tightened the joint with the intermediate pipe (two C-shaped half-rings that hold a flange to a ridge). Thus, once assembled there is a torsional load on the joint keeping the box in place. In fact, the corrosion failure happened near this joint, on the silencer side, meaning the box rotated on its hangers when the old box failed here. Is it normal for the box to be supported in this way, or have I put the rubber hangers on incorrectly? Could the corrosion be a form of stress-corrosion-cracking, where the exhaust pipe is under torsional load?
Joe