Rolling while brakes applied

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Several times after stopping at traffic light I notice my Trail slowly rolling forward. I give brake pedal more pressure and it stops. Is this almost undetectable if you are not looking out. Is this creeping due to brake assist? Does assist decrease during full stop thus causing 4R to roll? Any one else having this? Any thoughts and ideas?

 

[honcho44]

Mine does it because the idle bumps up because of air conditioning kick on.

 

[Acronym]

What honcho said, the idle kicks up for the A/C compressor kicking on, or any other reason. That and the brake pedal vibrate/hum feeling took me a little to get used to.

 

[KidVermicious]

Several times after stopping at traffic light I notice my Trail slowly rolling forward. I give brake pedal more pressure and it stops. Is this almost undetectable if you are not looking out. Is this creeping due to brake assist? Does assist decrease during full stop thus causing 4R to roll? Any one else having this? Any thoughts and ideas?

So, not a 5th gen, but I just played this game with my F150. If you have a spongy pedal that slowly sinks as the truck starts to creep but gets firm when you pump it, it could be a bad master cylinder.

 

[wfo9]

Mine does it because the idle bumps up because of air conditioning kick on.

^^this

 

[1engineer]

Mine does it because the idle bumps up because of air conditioning kick on.

Yep.

 

[marshal]

Don't forget that when the torque converter is unlocked like when you're sitting still, there is no mechanical link between the engine and the transmission. You literally have a giant hydraulic pump.

So, any change in engine RPM is exponentially applied to the driveline. A small uptick to compensate for the AC compressor would cause significant increase in hydraulic pressure.

 

[jbstrd]

Yep, same reason it sucks to wheel going downhill when your AC is on. Idle keeps fighting your brakes.

 

[Tstoutlv]

Mine did that really bad when I first got it. (Used) I changed pads cause they were getting low and haven't had a problem since. Using a/c and everything.

 

[BlackWorksInc]

This happens on the 4th gens as well, the issue is a disconnect in pedal feedback due to the hydraulically assisted braking system. Since pedal effort does not exponentially increase with pedal travel as is usual with "standard" assisted braking systems, it's very easy for the owner to have the brakes "lightly" engaged at a stop and when the A/C Compressor cycles the kick up in RPM is enough to nudge the vehicle forward.

I notice I do this in my 4th gen at times and just lightly pressing down on the pedal fixes the issue.

 

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Found myself few feet across crosswalk few times while changing stations on radio. LOL

 

[1000MPH]

I tend to use neutral a lot when I'm stopped at one of those LA type two minute red lights. But you got to be on your toes or you'll get rear ended when you lag after shifting back into drive.

 

[cbreze]

Never noticed it, just apply enough pedal. If someone is creeping a few feet across a crosswalk waiting for a light and not noticing, then someone is not paying enough attention to their surroundings or their 2 ton machine.
Had a cop tap my bumper once when I had a Tacoma, dude seriously wasn't paying attention. No damage, but was he red faced.

 

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That's nothing in 2 ton vehicle. You should of seen A1M1 driving. There is no worry about rolling. Don't even stop. Who needs to pay attention? But seriously, you never look away or down at your radio or phone while waiting in traffic. What are you a cop or some law enforcement?

 

[3William56]

My '09 Tacoma used to do it, and my new '15 4Runner does it. Kind of a mystery because it does when the AC is off and its not the rad fan either. I never liked that my Tacoma did it, and I always thought that it shouldn't. Now that I have a brand new 4Runner and it does it too, I'm less worried about it as they share nearly identical drivetrains. I still don't like it and find it pretty annoying sometimes.