A simple product in the sharpetooling range is this Load proportion Valve Spacer to suit 75/76/78/79 series Landcruisers
This spacer is to be fitted when your landcruiser has a 2 inch lift kit installed. When your rig has a lift, the rear brakes are not balanced properly due to the Brake Load Proportion Valve sensing the car is sittiing 2 inches higher than normal.
Essentially the car thinks that you are empty and that less brakes are required on the rear.
To get your brakes working effectively again, simply fit this spacer.