Brake drums warped

I dont buy that.

How much more do you think changing from rear drums to rear discs would really add to the final cost?

Even the cheap $12k kias come with 4 wheel disc brakes, so they can't be cost prohibitive.

 

betting it has to do with retooling the two plants. as they are already setup for drums its just easier to keep going with it.

 

Toyota: we're going to make the tacoma a superior off-road machine by keeping drums.

Chevy:we're going to make the colorado a superior off-road machine by adding a front locker.

 

The drum rear brake is better for off road. The drum brake is a far superior emergency / parking brake which is often needed offroad. You can use a disc rear brake for superior rear braking but used as a parking brake they suck. If you want disc and a good parking brake you have to add a drum brake to a disc rotor to get the best of both worlds which doubles up in cost and will greatly complicate the addition of Crawl control. With front disc already doing most of the braking anyway and the offroad model using a superior braking booster the lost of adding disc to the rear brake function is minimal in respect to the strength of the drum powered emergency brake. The drum brake has more brake lining surface area and better self initiated mechanical leverage to add braking force when used as an emergency /parking brake. Tacoma is a truck not a performance car so the rear drum brake is good enough for its intended purpose. Why add another couple of grand to the truck to get better road braking which you don't need.

 

Preach.
Finally someone understand Toyota's decision from an engineering point of view.
Drum > Disk in slow speeds due to more surface area.
I am 99% sure that drum brakes do not get hot when off roading at low speeds, < 15mph.

I can almost guarantee that that drum brakes are actually more expensive than disk brakes.
There's more surface material to add to the shoes, all at an angle, compared to a slab of carbon on top of a slab of metal(brake pads).

 

On the picture above I most likely did

I'd agree that, in general, the drums shouldn't get to warm at low speeds. There's definitely some exceptions though. Going down a long steep hill, when you're heavily loaded, sometimes 4-low in 1st isn't slow enough to stay off of the brakes. Secondly, and I believe this is what happened to mine, is when the Crawl Control is running. The brakes are pulsing, and this will definitely get the drums warmed up. Toyota even addresses this in the owners manual.

 

So I took it in today and the dealer is going to fully replace the drums. They tried to tell me that there's nothing wrong with the braking system, but they will replace them as a courtesy. They said the way that I drive the truck is causing the problem. Well, this ticked me off, and I spoke to the service manager about it. He was courteous and said that he'd run this buy an engineer. We'll see where this goes.

As a side note, I asked them to give me the transmission temp. operating range. No one in that darn place, including the service manager could answer, what I thought would be a softball question. I don't think that I'll be taking my truck back after I get this brake problem resolved. Does anyone know what the normal operating temp is?

 

It is usually from people's driving habits, but if you have ever seen a warped rotor turned on a lathe, you can without a doubt see that they are indeed warped.

 

Op do you not have the tow package with transmission cooler?

 

I do have the tow package.

 

Drill some holes and slots in them. Drilled & slotted drums.

 

LOL

 

You must not have worked on very many cars. Warped rotors are very common. I can guarantee I remove cast iron and not pad material with the cutting bit

 

Worked on many, purchased high performance brake kits, done lots of proper bed ins, and fixed supposedly warped rotors that were vibrating just by sanding down the pad material and rebedding the pads.

Of course when you turn a rotor metal is being removed. I've only ever seen runout measuring one side so that's inconclusive for whether the rotor is truly warped or the pad material is just built up unevenly.

These guys are smart cookies and I agree with them based on my own experiences.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

 

Someone told me that warping is caused by too tight lug nut torque...j.a.t.

 

Lol wut

 

I've heard that too. Makes no sense.

Pretty easy to warp drums once they get hot. Especially if you hold your foot on the brake or set the parking brake

 

Searched and found this. Did you ever figure it out? I'm having a similar issue.

https://www.tacomaworld.com/threads/braking-vibration.541013/#post-17478478

 

Theres even a TSB on it...

"Some 2015 – 2018 model year Toyota vehicles may exhibit brake vibration due to improper lug nut torque. Brake vibration can occur at any time if improper torque is applied to lug nuts. Even one lug nut over or under torqued can cause vibration."

 

I had out of round drums at 400 miles - the dealer replaced them. Symptoms returned at 900 miles - then they determined the axle had excessive runout, so they replaced the axle. Haven't had a problem since and I'm now at 7,500 miles.