I haven't removed the cap and rotor yet to see what exactly is inside, but what actually goes wrong. I'm ready to install my new 355 and was wondering if just changing cap and rotor was sufficient.

thx,
jonesy

 

If there is high mileage on the opti, it's generally considered prudent to just replace the whole unit.

 

Probably would have been a good idea to convert to the vented unit when you built the 355.