IIRC, wheel mis-alignment generaly manifests itself as a pull to the left or right, and wheel un-balance is a rhythmic throb, like washboard road, which increases and decreases in intensity as you approach a certain speed/speeds.
My 95 Pathfinder isn’t conforming exactly to either behavior. Yes, it does have a slight pull to the right, so my alignment may be a little whacked, but here’s the problem:
Under 40 MPH, no problem. Ever. Nice ride except a little noisy due to some well-worn mud-tires I’ll be replacing at the close of winter (they’re still pretty handy in deep snow).
Over 40, usually between 50-65, everything is just fine as well, until I hit a bump/seam in the road/other surface irregularity. It is at this time that all hell breaks loose. The front end starts shaking. Violently. To the point where it’s hard to steer. I once had another driver cast a horrified look into my cockpit and point to my left front wheel–so I’m guessing that the problem is readily visible from the outside. It feels like the wheel is trying to come off. Easing off the gas to slow down doesn’t help until I drop below 40 mph, and even then there is a noticable wobble which will turn into the nasty shake as I increase my speed. However, if I apply my brake the wheel comes back under control, sometimes without having to decrease my speed significantly.
Almost never happens over 70mph, but I seldom have the open roadway for that kind of fun. Everything looks fine upon visual inspection. Lug nuts are tight, halfshafts look goodtie rods, etc look ok. Apart from this problem, it handles just fine with no clunks or squeaks.
Is it FWD or 4WD? In either case, my first thought is a worn CV joint, which could give rise to just these symptoms. If it’s RWD, then it’s probably worn wheel bearings. You really ought to take it in to a shop - it doesn’t sound like a safe condition by any means.
I don’t think so, but I’m not positive. There have been lot of refinements in 4WD technology over the years. Hopefully GaryT or Rick will stop by. Either of them would probably know better than I. Almost certainly it’s being caused by some kind of joint or bearing with too much play in it caused by wear, that I’m willing to bet on.
Every wheel has a wheel bearing, it’s what allows the wheel to rotate.
Shaking that severe can have unexpected consequences - I once had a bearing go so bad that it overstressed the lugs and in a slow-speed turn they all snapped, sending the wheel rolling down the street by itself.
Very unpleasant.
Then again, I also once had some intermittent shaking from a slightly warped brake rotor and a sticky caliper.
The symptoms don’t fit typical patterns that I’m aware of. Usually play that disappears when the brakes are applied is due to a wheel bearing. Usually vibration in the 60-65 mph range, but not at lower OR higher speed, is due to wheel balance. Its coming on with a bump suggests a loose steering linkage or suspension part (tie rod end, ball joint, etc.), and a problem with a strut/shock absorber is also possible. Tires can do some weird things. And it could be a combination of two or more things. I’ve never heard of a CV joint giving this kind of symptom, though.
It sounds quite dangerous. I suggest having it dealt with yesterday.
I have a toyota MR2 Spyder, 2001. When driving at appx 60-70 mph the car occasionally has a shudder…the rear axle just swerves a touch. Letting go of the accellerator immediately solves the probem.
I’ve had all the tires replaced, balance checked, and inspected the suspension for anything ovbiously broken, and no dice…I’m out of ideas.
I had this problem 2 years ago with my '98 Suburban…and it was solved by:
Check (and balance if necessary) and rotate tires. If tires have uneven wear (worn insides or ridging), replace them. Continue to rotate remaining and new tires every 5000 miles to wear remaining (and new) tires evenly.
If you have tires replaced with uneven wear (that can’t be rotated to solve your shaking problem), then consider a realignment.
Sometimes the last shop that installed tires for your vehicle could have used defective equipment (e.g. - balance machine) and even though it says your tires are balanced, they actually may be out of balance. This happened to my vehicle once at a Costco Tire Shop. On the next visit, they explained this to me and rebalanced my tires on a new machine.
For the bearing: with the wheel off the ground, grab the tire at top and bottom (12:00 & 6:00) and try to rock it. There should be zero play. If there is play, look carefully at everything inboard of the tire/wheel assembly while it’s being rocked (much easier with a helper). If the wheel is moving relative to the spindle, it’s bearing looseness. If the spindle is moving, it could be a ball joint or a control arm bushing.
For steering linkage: with the wheels off the ground, grab each tire in turn at left and right (9:00 & 3:00) and wiggle (somewhat vigorously). You can probably make them move, but with noticeable resistance. If either side moves easily before resistance is felt, something is loose. Again, observe things while wiggling. Play will be in the steering linkage (inner and outer tie rod ends, pitman arm, idler arm, drag link if it has one) or control arm bushings.
Tire balance could cause this problem but I have never seen a balance issue manifest itself with a bump like the OP says.
Is there any vibration in the brake pedal when applied?
My gut feeling is that I would check the tie rod ends (both inner and outer) as well as any bushing that mount the control arms (according to one website I checked your trucks has upper and lower control arms not a McPherson strut)
also check the ball joints.
I suspect that the bushing that mount the control arms are DOA and need replacement. I once worked on a car with similar symptoms that had bad upper control arm bushings.
I think Gary T was off on his time estimate. This needs to be fixed the day before yesterday. Inigo, QED yes CV joint axles still have wheel bearings. I suppose that a BAD outer CV could maybe exhibit these symptoms, but it would a world class, worst anyone has ever seen, going to go kerplow in another 10 feet condition, to do this.
Have I mentioned that you need to get it checked out?
Thanks all. If I make it home alive tonight I’ll get my front end off the ground and wiggle my stuff. Henceforth I’ll let my woman drive it because, you know, this could be dangerous!
Bushings, ball joints…all that stuff, are those connections likely be obviously bad? Or are these the kind of things that can act normally when manipulated by mortal hands yet still be defective enough to cause symptoms?
I’m dead certain it’s not a warped rotor because braking action, even when the car gets the shakes, is Smoove.
It’s not a rotor, of that I am sure.
All of the following assumes that the truck is jacked up and supported on jack stands of course. If you don’t have jack stands, take it to a shop. A truck falling off a jack can ruin your whole day
Checking tie rods ends can be done by grabbing the wheel at the front and back and wiggling it back and forth. There should be no play before the entire steering starts to turn.
To check the bushings on the control arms, first do a visual (Don’t climb under the truck unless it is secure on stands, I mean it!) then grab the wheel at the top and bottom and check for play up and down. you may need a long lever to do this.
From the OP, I am thinking that the problem should be severe and obvious.
Good Luck,
Oh yeah, don’t do any of this stuff unless the truck is on jack stands.
By the time you find out that a ball or roller bearing is “going bad” it has already gone.
Failure begins with a tiny almost invisible bit of bearing steel being displaced from a ball, roller, or race. From that point on it is all downhill.
I had on old Ford van that would do the exact same thing. It was caused by a worn out idler arm or a bad balljoint. One broke and caused the other to break. Smooth roads were fine but anything over 35 on a bumpy road and the whole front end would shake. When I finally fixed it I had to replace the steering box, pitman arm, idler arm, center link, all 4 tie rod ends and the upper and lower ball joints. $400 for everything and the engine spun a bearing 3 days later.
Since everything from wheel bearings and rotors to ball joints and tires have been mentioned, let me complete the circle and offer my take: it’s your stereo.
It’s always the thing you least suspect. Replace it today. Get XM radio while you’re at it.