Brakes really hard almost not happening

[desertchick]

Hi we have a 1990 e350 box truck (retired uhaul truck) yesterday the brakes were fine. Today hubby had a 100 mile drive to make and he just called and said that the brakes were very hard to push down and he can barely stop the truck. What should we check first.

Thanks,
Denis

[MJ CORMIER]

You need a new booster, that woul be the big round thing behind the master cylinder.
MJ