Line locks are not a good idea for parking brakes, especially on older vehicles with iffy wheel cylinders. Any loss of pressure will allow the vehicle to roll, usually at the worst time. E bay, earlycj5.com, or any of the other early cj sites usually has somebody with misc extra stock parts to reinstall the original driveline brake. While much better than hydraulic park brakes, these are still not the optimal option since a lost u joint or other drivetrain part will still keep the system from working. Personally, I would recomend a swap to early Waggy brakes. These 11" brakes are a virtual bolt in swap and will give you not only vastly improved braking, but a rear drum cable operated e brake system as well.