If your Massey Ferguson 135 PTO roll pin is damaged, the best way to fix it is to replace it with a new part. There are several places online where you can purchase a new roll pin. Make sure to measure the diameter of the existing pin to ensure you purchase the correct size. Once you have the replacement pin, use a small hammer and punch to gently drive out the old pin and then gently drive in the new one. Make sure it is seated firmly before you use the PTO again.