Quote Quoting California Civil Code, Sec. 841.
Coterminous owners are mutually bound equally to maintain:
1. The boundaries and monuments between them;

2. The fences between them, unless one of them chooses to let his land lie without fencing; in which case, if he afterwards incloses it, he must refund to the other a just proportion of the value, at that time, of any division fence made by the latter.
Is the issue that the fence can be repaired, but you want to incur the higher cost of replacement and cannot get your neighbor to agree? You can make a claim against your neighbor under Civil Code, Sec. 841, but if you choose to replace a fence that could be repaired or choose to replace a fence with one that's more expensive than a fence equivalent to the one that has historically been used, you run the risk that a court would make you responsible for the additional cost beyond what was necessary to maintain the existing or an equivalent replacement fence.