New Truck Hot Brakes

Joe-Runner

New member
My front brakes have been getting very hot. So hot that you can feel the heat radiating while standing next to them, and they smell.

This is my 3rd 4Runner. I have towed trailers with them, mild off roading, driven all over Alaska and a significant portion of the lower 48 with them, and NEVER smelled hot brakes. The strange thing is the two most notable times I have smelled hot brakes have been on pretty minor drives, one of which was going entirely uphill!

Its a 2021 TRD ORP with 7800 miles. Since purchasing it I have installed a transmission cooler, put airbags in the back, 1 Inch spacers in the back, and Bilstein 5100s up front set to 1.75. I have done all mods and maintenance myself. The brake reservoir has not been opened since I purchased the vehicle.

Today I took off the front wheels, calipers, and rotors for inspection. Absolutely nothing out of the ordinary to mention, other than the fact that the front right rotor required the old screw-through method to dislodge it from the hub. Surprised it was stuck considering low miles on a truck that has only been between Texas, Utah, Nevada, and California with no towing or anyting crazy. The heat must have fused it on there.

I did a tiny bleed of the brakes for fun. The fluid smells strange vs any brake fluid I've smelled before. It smells like DOT4 mixed with full power Windex - if that makes any sense.

I'm stumped and can't find any stories of other 5th gens with this issue, and Id rather not run to the dealer over this. It's also strange cause it's not every time I drive, regardless of distance. You guys have any idea what it could be? What am I missing? Did lifting the vehicle put extra pressure on the system somehow? Seems impossible to me. Did the manufacturer put some weird crap in the fluid? Any input is appreciated.
 
Register to hide this ad
I doubt that your lift and other mods did anything to affect the brakes. Since it is still under warranty, I would have the dealer look at it.

Since it is affecting both sides, it could be the master cylinder is sticking or something in the ABS system.

Do you use both feet when driving, i.e. left foot on the brake and right foot on the accelerator pedal? If so, you could be riding the brakes which will make them overheat.
 
i had some corrosion in my front brakes early on. but we get salt and snow over here. My fronts were getting sticky at less then 5000 miles i believe. I went with a bbk, and never looked back. The brakes are known issues for people that see a lot of salted roads.
 
If you touch the front wheels after driving, is there a perceived temperature difference between the left and right front? It's unlikely that both calipers are sticking (but I guess not impossible) and you should feel a difference in heat. I had a seized caliper on a different car once and also smelled brakes. The temp difference between the wheels was easily detectable.

Any rotor discoloration at all? Bluish or dark kind of tint? Perhaps pull the pads and see if they are wearing evenly between inner and outer. That might tell you if there's an issue as well.
 
I doubt that your lift and other mods did anything to affect the brakes. Since it is still under warranty, I would have the dealer look at it.

Since it is affecting both sides, it could be the master cylinder is sticking or something in the ABS system.

Do you use both feet when driving, i.e. left foot on the brake and right foot on the accelerator pedal? If so, you could be riding the brakes which will make them overheat.
Nope, I do not use both feet while driving. Again I have put many thousands of miles on various 5th gen 4Runners without ever having this issue.
 
i had some corrosion in my front brakes early on. but we get salt and snow over here. My fronts were getting sticky at less then 5000 miles i believe. I went with a bbk, and never looked back. The brakes are known issues for people that see a lot of salted roads.
Absolutely no salt encountered, but I did get into a little bit of red sand in Utah.
 
If you touch the front wheels after driving, is there a perceived temperature difference between the left and right front? It's unlikely that both calipers are sticking (but I guess not impossible) and you should feel a difference in heat. I had a seized caliper on a different car once and also smelled brakes. The temp difference between the wheels was easily detectable.



Any rotor discoloration at all? Bluish or dark kind of tint? Perhaps pull the pads and see if they are wearing evenly between inner and outer. That might tell you if there's an issue as well.

As I mentioned I pulled everything apart yesterday and inspected very thoroughly. Absolutely no unusual wear, no discoloration, nothing interesting or noteworthy at all.

And yeah, the really strange thing here is that both fronts are get equally hot! I haven't noticed anything from the rears, but honestly they do such a minimal amount of the work that maybe they just aren't heating up as much.....

I guess I should look into if the master cylinder is causing the issue [emoji848] I'll leave that to the dealership though.
 
As I mentioned I pulled everything apart yesterday and inspected very thoroughly. Absolutely no unusual wear, no discoloration, nothing interesting or noteworthy at all.

And yeah, the really strange thing here is that both fronts are get equally hot! I haven't noticed anything from the rears, but honestly they do such a minimal amount of the work that maybe they just aren't heating up as much.....

I guess I should look into if the master cylinder is causing the issue [emoji848] I'll leave that to the dealership though.

Have you noticed dips in gas mileage? If there are severe brake issues then you might notice increased fuel consumption.
 
You might also check the service history of the dealership that sold it new, just in case the previous owner had it serviced for a similar problem.
 
My 2021 ORP was like that also, front brakes smelled very hot and also dusting tremendously. After 700 miles I changed the front pads to NAPA adaptive one pads and smell and dust is gone, I'll probably change the rear pads to those also even though the rear pads never have smelled hot or dusted too much.
 
Calipers piston stuck, rust. If notice early no need to replace burned fluid.
Both front calipers stuck simultaneously?

I was in San Antonio during the ice storm this last winter where they used very mild amounts of saline solution on the roads but there is nothing more than light surface rust down there.
 
My 2021 ORP was like that also, front brakes smelled very hot and also dusting tremendously. After 700 miles I changed the front pads to NAPA adaptive one pads and smell and dust is gone, I'll probably change the rear pads to those also even though the rear pads never have smelled hot or dusted too much.

Man, I don't want to change the pads out on a brand new truck. Not to mention it would seem this is a caliper/system issue, as opposed to a pad issue. It's an easy enough job but damn.... how many miles you have now?
 
I bought it brand new. No service record to speak of.
Sorry, misunderstood you. Thought you had bought it lightly used.

Since this is still under warranty for a long time to come, you need to get the dealership involved. Even if it's intermittent, they need to build a service history on this in order to diagnose. Maybe it's something they've seen before. Optionally, you could jack up one wheel, turn it back and forth a little, depress and slowly release the brakes, rotate the wheel again, repeat, and see if it binds one time. As fkheath said, maybe the master cylinder is sticking now and then.
 
A little update to the story: I just drove 230 miles today throughout mountainous terrain and after stopping for the day my rotors were virtually cool to the touch. Maybe the removal and reinstallation fixed whatever issue I was having...... could not duplicate.... [emoji106]

I will definitely continue monitoring!
 
If you continue to have issues, I would not suggest replacing OEM pads, but as others stated, take it in.
Period.
The pads are not the issue IMHO !
 

Members online

Forum statistics

Threads
278,316
Messages
3,554,120
Members
248,016
Latest member
Advally Service

Trending content

Back
Top