Here's the OEM bleed procedure for the 96-00 4Runners:
Take careful note of the procedure to 'bench bleed' the master cylinder before doing the rears, then the fronts. This would be necessary if the master reservoir ever got at all low (it is internally split, so you can get an air pocket even if the fluid looks about half full).
Also possible that you just hammered the seal in the master cylinder and you are loosing pressure internally there.
-Charlie
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'99 4Runner SR5 Auto -
4WD swapped
'89 Camry Alltrac LE 3S-GTE 5spd
'17 Chevy Volt Premier
'16 Honda Odyssey Elite
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