fiat allis fr15b wheel loader brakes

hey guys
i have a 1987 fiat allis fr15b wheel loader
the number on the plate that is rivited to the machine is
-chassis-R15BZTZ*590453
-motor-8365 25583


the brakes do not work, the pedal is hard and does not move.if i push the pedal really hard i hear some air but nothing happens.
i dont know much about these machines so any ideas can help me .

thanks

ps; if anyone has the brake and hydrolics service manual you want to sell let me know

:confused: