Braking Problems on Downshift (1 Viewer)

[pattay]

So I've posted a few times about the rough shifting on the 2016. It has 88k miles on it. However, I took it for a spin tonight on highway and city for over an hour and realized what my issue is. Whenever I'm braking and the car is downshifting between gears, it's lurching me front to back as it does so. Not a thunk/clunk or anything, just inconsistent braking.

I checked the CarFax report and it says the pads were replaced at 50k and the rotors were re-surfaced/replaced (not sure which).

I tried to re-bed the brakes tonight and when I hard braked from 60 down to 15, the wheel and car were pulsing, which might be a separate issue. But I noticed that I can't get smooth braking when coming to a stop to save my life. From 3rd gear down to 1st, it's just not smooth when the gears change. Could this be a pad/rotor issue? Stuck piston (I've had this before on a GX and 4Runner)? Or maybe it's normal and I'm not used to driving an SUV with this weight?

 

[CharlieS]

That isn't normal.

It is cheap enough to baseline with factory pads, rotors and hardware that I wouldn't hesitate to do that first. Toyota brand rotors are shockingly inexpensive for the quality, and factory pads are good quality, quiet and durable.

You will likely notice if you have a sticking piston since you will have unusualy uneven pad wear.

My 2016 that I bought used *from a Lexus dealer* had new pads all around, BUT they were some cheap auto parts store crap brand.

 

[rscoleman]

I have 2016 have not noticed issues you are speaking of out side of 1/2 shift of 2/1 shift prior to TSB. I had TSB done to my trans and that fixed the shifting. The front brakes got pads and surface at about 45k. Shudder in steering wheel when braking no odd feel in pedal. I was told that LC would need 40k to 60k brake work by dealer. You could just need pads and rotor/resurface. Really going to depend on how you drive. I did not own mine the first 14K miles. I think previous owner was ricky speed racer. I like to speed but around town I drive very normal almost boring I would say. If you can find local LC club get someone else with 2016 or newer to drive yours and let you know if they think it is normal. Good Luck

 

[TeCKis300]

Do you have any modification on your car? Tires, lift suspension work?

 

[pattay]

Do you have any modification on your car? Tires, lift suspension work?

None that I can tell. I was using the Pedal Commander but turned it off for now so I can diagnose the issue. Tires were replaced recently with same size stock Michelin Defenders, but I had the same issue with the last tires.

 

[pattay]

I feel more and more I just need to replace the rotors and pads. Last brake job was almost 40k miles ago and I don't know how the previous owner drove. Also, the pulsing when hard braking on the highway is suspect of bad rotors/pads.

I should add, I REALLY wish I knew if I had the TSB update for the transmission without having to beg a local dealer to check.

 

[TeCKis300]

I feel more and more I just need to replace the rotors and pads. Last brake job was almost 40k miles ago and I don't know how the previous owner drove. Also, the pulsing when hard braking on the highway is suspect of bad rotors/pads.

I should add, I REALLY wish I knew if I had the TSB update for the transmission without having to beg a local dealer to check.

Seems like the two things to attack first. Get a brake job and replace rotor and pads. Rear rotors are probably fine and its generally the fronts that get the bulk of the braking loads. And definitely confirm the TSB, even if you have to pay. Feedback from others suggest it is a night and day different with the update.

 

[CharlieS]

I feel more and more I just need to replace the rotors and pads. Last brake job was almost 40k miles ago and I don't know how the previous owner drove. Also, the pulsing when hard braking on the highway is suspect of bad rotors/pads.

I should add, I REALLY wish I knew if I had the TSB update for the transmission without having to beg a local dealer to check.

Yes, it would be nice to know without going to a dealer. TSB calls for applying Authorized Modifications Label under the hood indicating that the service has been done, but my dealer didn't do that, so it isn't a sure thing.

https://static.nhtsa.gov/odi/tsbs/2017/MC-10142499-9999.pdf

https://static.nhtsa.gov/odi/tsbs/2018/MC-10145752-9999.pdf

 

[pattay]

Yes, it would be nice to know without going to a dealer. TSB calls for applying Authorized Modifications Label under the hood indicating that the service has been done, but my dealer didn't do that, so it isn't a sure thing.

View attachment 3035454

https://static.nhtsa.gov/odi/tsbs/2017/MC-10142499-9999.pdf

https://static.nhtsa.gov/odi/tsbs/2018/MC-10145752-9999.pdf

Yeah, there isn't anything there. I'll try and push on the dealer to check the software.

 

[04UZJ100]

Aggressive braking on my 2020 will induce rather abrupt downshifts that are felt throughout the cabin. FWIW.

 

[pattay]

Update! Took it into the dealership. I was able to confirm I do have the TSB applied. When I discussed the braking with the tech, we checked a few areas. The brake pads are all OEM pads with 7mm of thickness left, so they should be fine. He took it for a test drive and noticed the slow pulsing/jogging on braking. They didn't have rotors in stock, so he suggested just turning the fronts and checking if the problem goes away. So we did that.

Luckily, it seemed to work. The braking is a lot smoother now. Only downside is that it seems to be a bit softer (takes a bit more pressure to stop the car), but it's a noticeable improvement over the issue I had.

In the future when the pads are worn, I'll probably end up replacing all pads and rotors together.

 

[Cincodemustache]

Turning removes metal, and mass, from the rotors providing you that softer feel when braking. Good you got your problem resolved. When you have new pads and rotors, any pulsing can usually be remedied by bedding the brakes.