Wheel Shimmy followed by Electrical Burning Smell

To start off, I bought my 4Runner about a month and a half ago. It is an 03 limited with the 4.7l V8 and roughly 138000 miles. I have had no real issues with the truck since I bought and I even had the dealer put a new timing belt on it included in the purchase price.

So yesterday I was driving down the road with my wife and our 8month old. Everything was fine driving 55-60, I hit a stop light and once I returned to 55-60 the wheel started to shake pretty violently. A moment later I started to smell burning. I know the smell of wires burning and that is what it smelled like. So I pulled off the side of the road and shut the truck off. The burning smell went away. I called a tow truck and had it towed to the repair shop my father-in-law works at. I looked around to try and find where it was coming from and found nothing.

I was thinking that maybe since the vehicle has electronic braking maybe that is where the problem is, since the shaking of the wheel and the smell happened at the same time? I may be wrong. I'm looking to see if anyone else has had this problem before or maybe someone could tell me what it could be.

Any help would be great!! Thanks!

 

Couple questions for you on your problem?


Weather conditions?


Maybe snow/ice build up on one wheel caused shake.


With shake, some wire/wires or pc of plastic touched exhaust.


Just throwing possibilities out there for you.

 

Well we jsut had a pretty nasty ice storm, but the truck was in the garage for most of it. I was maybe like 2-3 miles from my house.

I'll have to look at that stuff tomorrow morning when it get put on the lift.

Thanks for the ideas though!

 

Sounds like you may have had a caliper stick.
The scenario is a duplicate to my old truck. Long drive at highway speed. Stop sign. Shake in wheel after about 2 miles. Brake pull while stopping after shake. Smell.

It does happen.
The only way to really confirm is drive and use the brakes. Stay close to check area. If it starts go to the check area and jack up the front and spin tires. If there is an issue you will have a hard time turning one of the wheels.

 

Assuming it is the caliper sticking, what would need to be replaced? Caliper? or would it be in the master cylinder or lines?

 

Yes replaced. A master would be applying to both causing locked up brakes.
However with that milage if you find a sticking caliper IMO you should replace both. I have seen more than once replacing one caliper ended up being the other side also needing replacement soon after. You MAY be able to see signs of overheating or gazing between the two.

 

Like on the Rotor? Like the blue color when steel is heat treated? Dont mean to sound like a moron, But I'm a machinist not a mechanic. lol.

I can replace the calipers and get a pretty good price on them through my father in-law. so this would be good if that was the actual problem. would the burning smell just be from the pads rubbing continuously?

lastly, is there a way to definitively tell which calipers are suspect? like to tell if it is likely the front or the rear.

 

If you read my other post I gave you a way to start checking for a sticking caliper.

Yes the smell would be from the excessive pressure on the rotors from the pads.
In a severe situation blue could be seen. Just look for a difference between the left and right.
More off color...
Your not a moron.

 

Yeah, I read that in your other post. Just wondered if there was a more definitive way to say "yup, that's the one".

Thanks for the help! I really appreciate it!

 

The reason for doing it this way is you want to take the guess work out. Your trying to find an issue. A educated guess is just that. I don't want u replacing something you don't need. If you can nail down a stuck caliper then you know it will be repaired. If you can't find a stuck caliper, it could be another issue. Boy I wish things were more definitive. I would have a lot less white hair.. Hehe
Good luck.
Your welcome ....

 

In my professional opinion, IF the result is found to be a sticking caliper, with that kind of smell and vibration, I would replace the rotor as well.

 

yeah, and considering the dealer told me they just resurfaced them you can bet that they will most likely be warped.

We will see once I get the problem child isolated.