Stiff pedal when applying brake

2000 TOYOTA REVO
80,000 MILES • 2.4L • 4 CYL • RWD • MANUAL
Avatar
JHONG VALERA
  • MEMBER
  • 1 POST
It has been a while since I have this hard pedal brake problem but I just let it stay as it is. Maybe I used to it already. I know it is dangerous but I know how to handle it already. Went to check with the mechanic about this and it was diagnosed to be a broken brake master. So we changed the it but the problem still exist. Unsatisfied, went to another car shop and they changed the hydro-vac. Still, nothing happened. As far as I could remember, I changed the brake master and hydro-vac twice but the problem remains. I have heard from my friend that the vacuum/air from the alternator is not working properly? I checked it myself, and found out that there's a small hose from the back of the alternator connected to the hydro-vac. This must be the thing that my friend was referring to. Does it contribute to the hardening of pedal break if the vacuum from that hose is weak? I planned to have the whole braking system checked first before replacing another. By the way I am only using a Japan made replacement. What is really the cause for this?
May 9, 2017 at 12:44 AM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
Hello,

It sounds like the vacuum is low to the booster. With the engine running please plug in a vacuum gauge to see what the vacuum reading is at the booster. Please take pictures of all components you are taking about so I can see the system.

Please run this test and get back to us so we can continue helping you.

Cheers, Ken
May 9, 2017 at 2:37 PM
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,113 POSTS
Your friend is correct. The vane type vacuum pump attached to the alternator is not working. As such you have no vacuum to the booster and a hard pedal. The common cause for this is that moisture has caused corrosion on the rotor which caused the vanes in the pump to stick or they are very worn. The pump is re-buildable if the interior isn't badly scored.
May 12, 2017 at 7:19 AM
Advertisement