Stiff break pedal

Does anyone else find that after being parked for more than a few hours, there is no break pedal assist before the engine starts? My break pedal feels like a rock until it starts then moves normally afterwards.

 

normal. you won't get assist when off, on any car....

just checked mine, if you pump the pedal after its off & sitting, you will get a few very minor pumps out of it & then it stiffens to a rock.
There's no assist when vehicle is off..

 

Yes!

On every vehicle I've driven for the last half dozen decades.

Well, except those with manual brakes. Off or on, those work the same.

 

I’ve always had a reserve vacuum that remained unless I pumped the breaks like slater described. I never had the break vacuum leak when just sitting.

 

drive it, put it in park, & let it sit overnight...
try again in the morning after it sits overnight, as mine sat overnight when I checked it.
not totally hard from the get go...
1 pump probably went to down 1.5"?
second pump 3/4?
third 1/4?
you get the point.
regardless doubtful that you have an issue im guessing...

 

Sounds like it might be part of the electronic brake system. When engaged, the system uses an electric motor to engage the rear brakes. It would make sense to me that this is putting back pressure on the hydraulics a bit thereby stiffening the pedal but I haven't tested this. Could easily try disabling the electronic parking brake and see if you get the same situation.

 

i dont know about the none hybrids but my iforce maxx does not have vacuum booster. its electro hydraulic master cylinder now. a lot of manufactures are using these, its easier for them to make the vehicle have automatic braking features with that style of brake master cylinder.
anyway so there is no residual vacuum to deplete anymore when bushing brake pedal with vehicle off. you just have manual brakes. Also with this style you will notice that the brake pedal is always very high and stiff since you are pressing on a sensor instead of directly to the mastercylinder.

 

^The electronic booster has been used on Off Road trims for the past 15 years (and past 23 years for 4Runners). There's still a direct mechanical connection between the pedal and the MC piston. The difference is the vacuum assist has been replaced by an electric pump. Toyota also uses this system on hybrids (since early Prius models) to keep pedal feel consistent with regen braking. With this system you can get full brake assist with engine off but power on, useful for brake fluid flushes.