Unfortunately, there is no "fix" for a leaky brake line other than completely replacing it. Brake lines are under extreme pressure and NOTHING will stop the leak. Attempts at patching a brake line only endanger the occupants in the vehicle when it busts free (and it will)posing a crash hazard. If you have very thick soled shoes, and a very strong left leg, you might try opening the drivers door and dragging your foot. Otherwise, PLEASE have a qualified technician replace that brake line!
Try Nissanparts.com. I just bought one for my 1981 280zx.
look at the under hood diagram
The 1981 Chevy Cheyenne brake fluid tank can be found attached to the firewall in the engine compartment. The brake fluid tank will be on the drivers side of the firewall.
A 1983... what?
Any DOT 3 fluid. Brand makes no difference.
Try using the external handles for starters...
ngk plugs are .31 to .35
You can find parts for your 1981 Datsun 720 King cab at most auto-parts salvage stores. Many of the parts are still available from your local Nissan dealer.
Brake Tests - 1981 is rated/received certificates of: Australia:G