Shaky when brakes applied...

[shantelleclarke]

I'm not too sure if someone has already posted this or not... I'm new to the whole forum thingy.

I have a 2000 4Runner - Limited. I've noticed that whenever I apply the brake at highway speeds the steering wheel 'shimmies'. The harder I apply the brake, the more the steering wheel moves. Not too sure what is causing this. I have had my brakes looked at and they are fine.

HELP!

 

[alaskaman]

when you say you have had the brakes looked at what have they done? do you have an ABS system on your 4Runner? or some some of electronic brake force application?

 

[shantelleclarke]

Ya... there is ABS.
The pads, rotors, shoes and drums were all looked at...

 

[alaskaman]

I would suggest draining and filling the brake fluid by an experienced dealer and check for leaks.

 

[drmorbius]

Ya... there is ABS.
The pads, rotors, shoes and drums were all looked at...

I would look for loose steering parts like the rack mounts and linkage ends

 

[nc211]

This sounds like the classic warped rotor syndrome. Just because they were looked at, doesn't mean they aren't warped. I had mine "looked at" by the dealership, was told everything was fine. I then took it to my indi shop and had them turn the rotors, at which point he told me they were warped quite badly. The shimmy I had, which was exactly like yours, is gone. I don't think a person can tell if a rotor is warped by visual inspection alone, and chances are they didn't drive your truck. If it was a dealership that did your inspection, I wouldn't be one bit suprised if they just didn't want to turn the rotors, period. I've run into that a few times. I'd spend the $50 bucks at your local brake shop and have them turned. I would also make sure the lug nuts are all evenly tightened to the prescribed torque settings "83 lb's on my 05". I recently had a vibration at highway speeds from the back. I also had the wheels rotated and balanced a few weeks prior. I checked the lug nuts, only to find a variance between 75 and 105 lbs torque. After resetting all at 83 lbs, no more shimmy/vibration.

front to back pulsations can be warped rotor related, or low pad depth "typically". But side to side shakes are almost always rotor related.

 

[clem18]

This sounds like the classic warped rotor syndrome. Just because they were looked at, doesn't mean they aren't warped. I had mine "looked at" by the dealership, was told everything was fine. I then took it to my indi shop and had them turn the rotors, at which point he told me they were warped quite badly. The shimmy I had, which was exactly like yours, is gone. I don't think a person can tell if a rotor is warped by visual inspection alone, and chances are they didn't drive your truck. If it was a dealership that did your inspection, I wouldn't be one bit suprised if they just didn't want to turn the rotors, period. I've run into that a few times. I'd spend the $50 bucks at your local brake shop and have them turned. I would also make sure the lug nuts are all evenly tightened to the prescribed torque settings "83 lb's on my 05". I recently had a vibration at highway speeds from the back. I also had the wheels rotated and balanced a few weeks prior. I checked the lug nuts, only to find a variance between 75 and 105 lbs torque. After resetting all at 83 lbs, no more shimmy/vibration.

front to back pulsations can be warped rotor related, or low pad depth "typically". But side to side shakes are almost always rotor related.

I believe in setting the the correct torque in tightening the lug nuts. I had the shimmy at 45k a few months after I had the tires replaced. The rotors were not smooth but does not require replacement or turn. Only when I tried removing the lug nuts to rotate the tires that I notice how tight it was on . Re-torque with 83lbs all around and It was gone for a good 15k until I needed a replacement, never bother with turning the rotors.

 

[Finger]

I took my 2005 4Runner for 50,000 mile service. Just oil change and tire rotation requested. They said the shimmy they detected in the road test was due to my brake rotors and they should be replaced. My battery was going bad also and the computer recommended replacement. Is it normal to replace rotors and battery after 50,000 miles?

 

[nc211]

This past Saturday, going 75 mph on the freeway, hit the brakes to slow for the exit...steering wheel shakes back and forth at rapid speed. I just had my front rotors turned not 2 weeks ago, and it doesn't do this at city speeds. So, I don't think my previous comment really applys anymore. I'm not really sure what would cause this. My rotors have PLENTLY of depth left. When they were turned, they were still at the very upper end of depth spec. Almost 90% of the miles on my runner are straigh highway.

 

[riverwolf]

OP has a 2000 while it looks like the rest of us are talking 4th Gen. Not sure how similar/different they are.

I definitely think there's something going on with the design or tolerances some where. I saw another thread where someone described what sounded like his rotors actually had a bit of "play" around the lug bolts.

On my own 2003 Limited, I get a shimmy right around 65 that disappears completely below 60. It's also less at 70 than 65, but not sure if it disappears north of 70...very little time spent there and most braking at that point is just cancelling cruise control and letting aerodynamics do their thing. Really peculiar thing is sometimes the shimmy isn't there at all, other times it's light enough that you think it might just be road imperfections. And then, every once in a while, it tries to rip the steering wheel out of my hands.

I'm with nc211 and ready to rule out warped rotors as the explanation for the frequent 4Runner brake shimmy postings. I'm beginning to wonder if the the lug nut torque spec isn't tight enough, possibly in combination with too much slop in the rotors and/or some extreme sensitivy to minor wheel balance issues.

For instance my shimmy seemed to be significantly reduced for a few days after I rotated tires last month. I'm pretty sure I'd been running a patched tire on the front up to that point, moving it to the rear axle with the rotation. Also balanced all air pressures while I was rotating. Tires show no signs of uneven wear nor do the still original brake pads (51k). After a few days to possibly a week, the shimmy seemed to return to its usual force. But, as I said, I have some days, like this morning, where it's virtually nonexistent.

-Brent

 

[pconner748]

Dude just have them Turn the Rotors, you should not need new ones.

Pat

 

[Mr. Leary]

This is a tricky issue with 3rd gen 4runners. You could have warped rotors, or you could be experiencing heat fade. The rotors are very thin. When they get heated up... like braking from highway speed, they develop an imbablance that is not present / hard to detect when the rotors are cool. This is why so many folks do the Tundra brake upgrade. Not sure this is a problem you can fix short of upgrading the brakes. At one point I replaced my rotors, and less than six months later I was right back where I started.