We have recently seen two sets of Brock exhausts for Long-EZs with cracks around the flanges, in one case the flange itself was cracked in half. We have also received a written report from one other builder who had a similar problem. We do not understand why, suddenly, there are some failures of these exhaust systems. We ran two of these systems for over 1000 hours each here at RAF and Dick Rutan has almost 1700 hours on his Brock exhaust system to date.
The Long-EZ was introduced in 1980, the first homebuilts started hatching in 1981 or so. Not one report of a cracked exhaust system until recently. While we do not believe this to be a major problem, we do believe that your exhaust system should be very carefully inspected using a bright light. If any sign of exhaust gas leakage is found anywhere on the exhaust pipes, the entire exhaust system should be removed and thoroughly cleaned and then carefully inspected, paying particular attention to the welds and especially the welds holding the stainless steel flanges on to the tubes.
If any cracks are found, they may be TIG welded if they are not too bad. However, if the exhaust has very much time on it, even the TIG welding won't hold for long due to contamination. In this case, it may wise to simply install a new exhaust system. In any case, new exhaust gaskets must be used when installing any exhaust system unless you use approved re-usable gaskets. Keep in mind that if there is an exhaust system leak inside the cowling, it may be possible for some carbon monoxide to find its way into the cockpit. A carbon monoxide cockpit indicator is an excellent idea.