You might want to check if your accumulator is rotted through and needs replacing. Stock they are wrapped in foam, which traps water and causes them to break down and parts enter the AC system, frequently causing leaks.
Here's a pic of a stock accumulator after about 3-4 years.
Common problem with Tours due to the foam.
The foam can be easily un-wrapped (so I've been told, not tried yet) by the clamp. The new one's come without the foam.
