shimmy in the steering upon hard rapid braking...

[JayQQ97]

Gen2 single cab
4speed auto
80.7k miles ... now at 87,7k miles on 10-Marz-2o24

coming on off the freeway or rapidly slowing down from freeway speeds 70+ mph
there is a noticeable shimmy vibe in the steering wheel with both hands on

brake pads replaced 25k miles ago ... now over 33k miles ago
rotors are original

could this shimmy be anything else besides the rotors being worn and/or warped?

 

[tacojoel]

It's either warped rotors when hitting the brakes, or a tire balance issue.

 

[JayQQ97]

tires were just rotated and balanced 1k miles ago

as long as its not a bearing going bad or something in the rack and end links

 

[tacojoel]

Those are the most likely cause I listed. It's still remotely possible you can have worn front end parts.

 

[JayQQ97]

13 years and 80k miles of wear, mostly city stop and go on this rig

 

[Rock62]

It could be any of the front end suspension components. The mileage you have and your maintenance routine suggests anything up front could be worn. Bearings, UBJ, LBJ, bushings, rotors, brake pistons, wheel bearings, tie rods, calipers.

I would think a tire balance issue would cause vibrations under all driving conditions, not just braking.

 

[tacojoel]

I once had a bad set of new tires. The tire shop tried multiple times to balance them. I had vibrations at 40 mph, and 70 mph...The vibration would move around whenever a new balance job was done.

 

[JayQQ97]

81k miles is not a whole lot of mileage i would not think

 

[Rock62]

81k miles is not a whole lot of mileage i would not think

Depends on the maintenance and driving conditions and usage.

 

[JayQQ97]

good lord to the heavens if this is something now in the steering components

so i was exiting the freeway on a cloverleaf exit



tight AF turn
got on the pedal to get to that red light and the steering wheel started a more nasty wobble vibe-in-hand than the usual

wheel bearing is roasted?? or whut is it now

 

[Rock62]

Well.....you could continue to guess at the problem
or
keep driving it to a complete failure
or
stop driving it and start to diagnose the problem, then repair it.

You have choices.

 

[tacojoel]

It sounds like a classic condition of needing new rotors. I'd have the rotors checked with a dial indicator...I bet they're out of spec.

 

[JayQQ97]

Could be the wheels out of balance if the rotor swap is a no go?

 

[tacojoel]

You claimed this under braking did you not?

 

[Rock62]

ROFLMAO.................

Shotgun guessing diagnosis. Always successful, if you have enough parts to load the parts cannon.

 

[JayQQ97]

Whut do all I need to buy for it if parts are removed

 

[Rock62]

Perhaps @tacojoel can provide a suggestion. Me, I'm stumped to make a proper answer...........

 

[tacojoel]

Jay...did you not read post #12. Start there.

 

[JayQQ97]

rotors

 

[Rock62]

Yes, rotors.

To check you'll need a couple of measuring devices.

1. Micrometer or Vernier Caliper to measure the rotor thickness. Rotor has a minimum thickness, if less than minimum, then replace.

2. A dial indicator on a magnetic base. Place the base on the upper or lower control arm. Set the tip of the dial indicator against the side of the rotor parallel to the hub axis. Set the Zero ring. Slowly rotate the rotor making note of the total indicator movement. This will show the magnitude of any warp (ie runout). Here again, there is an acceptable tolerance. Outside of the tolerance range is replacement.

Be aware. The runout measurement will be dependent on the condition of the wheel bearings. In other words, bad wheel bearings can affect the measurement.

If these checks are within acceptable limits, then the problem lies elsewhere.