Brakes lock up ?

2018 4Runner OF
Anyone have the problem of your new 4R brakes locking up when pressing firmly like when needing to slow way down like if your on the free way and all of a sudden traffic is backed up? I wouldn’t expect pressing the brakes firmly then all of a sudden it catching and locking up the tires.

The damn thing locks up and starts swaying and scares the hell out me me... and almost, if not dangerous. Like a new rental car, how the brakes are very touchy but worse. Do you think the brakes need adjustment ?

 

Sounds scary as hell and I hope I never have that problem.
If it happens often and you can easily replicate it I’d suggest taking a service tech for a spin.. make sure to for warn the tech of what’s about to take place unless you wanna really piss em off

If, by chance you don’t tell the technahead of time- please set up a GoPro and record for us to see later haha

 

Hmmm a braking assist feature not working properly!!!

 

i know when you really lean on that pedal its like throwing out an anchor. the day i picked mine up i almost put my wife through the windshield!! they have mellowed a bit since then luckily

 

Disc brakes are non-adjustable. You will get used to your brakes soon.

 

OP- did you ever get this figured out? i would think the anti-lock brakes would kick in before locking up. which makes me think this might be and anti-lock brake issue?

mine don't lock, but they squeak very often. didn't do it at all the first couple of months of ownership. but now they're squeaking a lot. weird. and its multiple wheels, not just one.

 

My 2017 does the same thing. Unexpectedly, at fast road/highway speeds, I press firmly and they lock up and send you into a skid until you take your foot off completely. It's happened to me around 5 times in the 16 months that I've had it but I can't reproduce it because the vast majority of the time the ABS works as expected.

 

I have a 2016 Limited, and I can vouch for this too. It's happened to me 5 times in the 5 months I've owned it.

 

This happened to me on my 2019 many times, it is scary, but the worst was I had to brake hard and pull to the side of the road due to a car cut in front of me, the bakes did lock but when it hit dirt it was like slipping thru ice.

 

I would contact Toyota, and i’m not talking about the dealership. Trying to replicate this for them is dangerous to say the least. Let them know you are afraid to take your family in it, and would not like to endanger other people on the road.

 

My 2019 has locked up several times... mostly while it was raining.

 

Yeah for the first month or so.....I attributed it to being a learning curve and getting comfortable with the new ride and having way better breaks. It doesn't happen any more.

 

I've also had this a couple of times. Both have happened in dry conditions and were the result of being cut off / people not signaling (we have the world's best drivers in Florida). Called the dealership, but we couldn't replicate it. Definitely unnerving.

 

Its the nanny brake assist feature toyota added, to put a bandaid on the "runaway" issue awhile back. If you take your foot off the gas and press on the brake " to fast" it multiplies the braking force and would lock up the brakes if not for the abs. Still sends anything not tied down flying into the dashboard.

"Brake Assist (BA) is a supplementary braking technology that Toyota has used since 1997 and works in conjunction with ABS. Research conducted by Toyota shows that nearly half of all drivers do not step on the brake quickly and strongly enough to stop the vehicle in the case of an emergency, so Brake Assist was developed to help with that situation.

Brake Assist detects an attempted emergency stop based on the level of force and the speed with which the driver steps on the brake pedal. The BA system then adds additional braking pressure, helping to bring the vehicle safely to a stop in the shortest distance possible. " https://blog.toyota.co.uk/toyota-car-safety-braking-technologies

 

Digging up an old one here. Did anyone ever figure this out? I have a 2011 I just picked up. Every single time I slam the brakes, the rears lock. The ABS unit doesn't fire any bypass valves at all. It's like the ABS has failed. I have a pretty advanced autell scanner. No codes, and the wheel speed sensors are good, I've seen the live data. Speed is accurate, goes to zero on lock.