My old Toro gas string trimmer uses a very hard to find trimmer line with a diameter of around .130" and it comes in precut chunks that are about 12" long. I'd estimate the trimmer and line at about 15-20 years old. Lately it seems like I thread in a new chunk of line yet after very minimal trimmer use it breaks off near the head and causes out of balance trimming. Does this nylon line get brittle over time?? I hope not because it's 'pert near impossible to find since Toro must have used a very unique style head for this trimmer. Are trimmer heads real fussy about the exact diameter line? I see replacement spools of .105 but don't know if this would fit too loose.