Front Brake Seals
Seized brake calipers is  a common problem on FJ's.  The cause is down to corrosion behind the seals that cause the seals to push out of their groove and grip the brake piston so causing the seisure.
The pistons should be easily be pushed in with finger pressure, if you find this is not the case then the answer is to strip the caliper down. You must replace seals if the caliper is dismantled.
FRONT SEAL SETS ARE SUPPLIED TO FIT BOTH CALIPERS.
Each seal set consists of the required number of wiper and pressure seals, caliper seals (For when you split caliper) hose copper washers, bleed nipple/s and cover/s and a satchet of rubber grease.