Most brake fluids, typically used in older vehicles, are hygroscopic (absorbs moisture).
Rust can develop in the master cylinder and migrate through the brake system.
At minimum, I would flush the whole system of old brake fluid.
A thorough brake job would include a cleaning or replacement of the wheel cylinders.


"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."