Hi, my wife's corsa'sheat sheild over the front silencer has fallen away. Held on with six nuts, but the thin metal has perished around them. Easy I thought, remove the nuts, stick some large washers in front of the nuts and put them back on again. Except they were so badly corroded that four of the studs sheared off, when i usd a socket to remove the nuts, even after I soaked them in WD 40 for an hour before trying to release them. I would prefer to put the shield back on. Any ideas how? Could I drill out the studs and put self tappers in place for exmple.