Brake drums warped

Has anyone had problems with warped brake drums? Round 1: my drums warped back in January, after I used my crawl control. The dealer turned them and problem fixed. Round 2: it's had a slight shake when I brake. The shake isn't quite as bad as last time, so I took it in to see what they felt. The dealer said that they think it's the drums as well, but they wanted to look at it some more. I have been using the crawl control again too. I'm 99% sure that this is the cause of it. I don't tow, and both instances have happened after I used the CC. does anyone have any similar experience?

 

Can you describe the situation you were in. Crawl control controls the speed so if you needed braking that bad I can only assume you were going steeply downhill and for a long time.

I've only used crawl control once so far and no issues.

 

Warped rotors is a myth in my experience. the vibrations are caused but uneven pad material distributed across the face of the rotor. Those hard stops where you lay on the brake and come to a complete stop? where your pad sits at the stop it's baking on a nice thick layer of pad material right in that spot on the rotor.

Most folks that complain about Warped rotors keep seeming to have them because they are ultimately causing them with their braking habits.

 

This. You'd be pretty hard pressed to warp your rotors. It's uneven pad material distribution

 

The first time that I used CC I was stuck in a ditch.

After running the system for 2-3 minutes the tranny overheated and I shut it down. After letting it cool back down, I tried CC one more time and popped it out of the hole. I liked how it got me un-stuck without so much as me shoveling one grain of dirt. Later, when I got back to pavement though, I could tell right away that the drums were warped and knew that it had to be from the above incident. This is when the dealership turned the rotors for me. I've used CC a few times since then, once to get up a 100' steep, sandy hill. I only used it this time for 20-30 seconds top. There were no issues after this use. Most recently I've used it to go down some moderately steep inclines that were a little to steep for 4-low 1st gear with a distance of, I'd guess, no more than 300'-400'. The CC wasn't working very hard either. Since then though, I've noticed a more subtle shake when braking. I'd thought that maybe it was the rough streets that I drive on. When I looked it up in the owners manual, it doesn't specify a specific length of time, but is very vague and says "If CC is used continuously for a long time". I'd like to know what Toyota considers a long time. So far I'm partially impressed with the system. It's gotten through a couple tough obstacles, but it's also causing some reliability issues. I really wanted a standard transmission, but went with the auto because of the CC. Now I wonder if I didn't make a mistake. What do you guys think?

 

This is interesting, I am not sure.

I think CC shuts down on its own after 12 minutes but don't quote me. I read that somewhere.

 

It has some sort of built in failsafe to keep the system from overheating

 

I've never heard that before. It was the drums that were warped, not the rotors. I'm a little worried about the design of the system because I don't believe that drums dissipate heat as well as rotors. I don't know of another vehicle in Toyotas lineup that uses drums with the CC system. I hope that this isn't an inherent flaw in the system.

I'm definitely no expert, but unless I'm wrong, you need to check the runout of the drums with a micrometer. If they are out of spec, then they get turned to bring them back into spec. I'd bet that the mechanic at Toyota did that after the first incident, because it worked fine for quite some time. They never said a thing about changing the shoes out.

 

I've read or heard that somewhere as well, but in the Tacoma owners manual it doesn't say that. I don't think that Toyota can really specify a certain length of time because sometimes the CC is working hard, like when I dropped it into the ditch and other times not so hard, like when I used it to cruise down that hill.

I left it at the dealer tonight, as it was getting to late to get it resolved today. I'll let you know what they say tomorrow.

 

Drums are TERRIBLE with heat which is the primary reason why drums were replaced. Your post was a bit confusing because you reference both the rotors and drums. I've had drums wear differently before and the shoes should adjust after some time. I would just have the drums remachined.

 

I see what you're saying about being confusing. I meant to say drums in the OP. I'm going to go and edit that. Thanks for the catch.

 

Sorry guys, I meant to say drums, not rotors.

 

I'm a little worried about them being re-surfaced again. If, in fact, they are getting to hot, then re-surfacing them will only make things worse, I'd think.

 

Drums and rotors can only be resurfaced to a specific depth. After that, you need to get new ones. As long as they can be resurfaced, there are no issues.
Still not sure why Toyota continues to use drums in the rear...can't be to save money when they cost a good penny. There has to be another reason.

 

I watched an interview with a Toyota engineer specifically addressing this. He said that the drums perform better off-road. If this is the case, why didn't they put drums on the FJ or the 4 Runner?

 

Did you park the truck with the parking brake while the brakes were still hot from using the crawl control? That could cause uneven deposits as described above.

 

Exactly. Why aren't they on Toyota's off-road flagship in the Land Cruiser?

Sweers saying drums are better for off-road is just an excuse for Toyota getting cheap.

 

I haven't replaced drums in a while but they are in general less complicated and less expensive. shoes, springs drums, etc are cheaper than calipers and rotors.

 

You know they actually measure runnout of the rotors with a dial indicator which will measure how warped the rotor is..... to the thousandth of an inch.


Not saying this is the case with the op. Warped rotors isn't a myth.

 

My drums were out of round from day one. The dealership tested them with a micrometer to confirm they were not round and turned them. Smooth braking ever since.