Hi,
i have a 240SX used for drifting
i need a trong handbrake so i decided to remove the stock cable brake and install an hydraulic one, from D2 with a 3/4" pump

we changed oil and bleeded it correclty, in fact front brake work okm but handbrake doesn't lock unless i really pull it as if i would brake the lever off the chassis

at rear i have 250mm toros with the stock small 1 piston calipers and small pads

what do You suggest to have a really strong and locking handbrake?

If it were me I would upgrade brakes and rotor. Those tiny things can only hold so much force you need something a little bigger.