What would cause a 2000 f-150 to have vibration at 60 to 68 MPH the tires are new and have been balanced 3 times by two different shops?

Answer 1

A simple wheel balance will cure most vibrations. But if that doesn't cure the problem your problems may go deeper.

Inspect the rim--inside and outside--for any damage. Also look at the tires--if you see any bulges or uneven wear of the tires, consider them in the "probable cause" category.

Nothing obvious? Take the car for a test drive. When the vibration occurs, is it while you're accelerating through a bend? That means it's both torque and speed sensitive. When you pull back to your garage, inspect the axle shafts, looking for damage to the boots. Constant velocity joints can wear out. But if the boots are intact, the clamps are holding them at each end, and there's been no loss of lubricant and no intrusion of road film, then they're probably in good condition.

If the vibration is not related to torque, shift into Neutral and let the vehicle coast at the problem speed. Still have the vibration? It's speed sensitive pure and simple. This could be the source of your troubles, even if the wheels are balanced and the tires are good. It's not a powertrain or driveline issue.

Jack up the front wheels by the control arms, so they're off the ground, and support them with safety stands. Grasp each wheel, holding it first at the sides, then at the top and bottom. See if you can rock the wheel in and out and if you can feel any looseness, which indicates a loose wheel or worn wheel hub bearings. Wheel bearings (and the front bearings on many rear-drive cars) are well-sealed and often are life-of-the-car without lubrication. However, if you've been on a lot of secondary roads, or glanced off a curb hard enough to bend a rim, they could be worn or damaged.

Your Ford has adjustable front wheel bearings, and finding a lot of free play in these is not surprising. To adjust, remove the cotter pin, tighten the wheel bearing nut to about 20 ft.-lb. to seat the bearings, and back off so they're just free but have so little play that you really can't feel it. Then line up the slot in the spindle with the nut and insert a new cotter pin.

You may not feel free play in a front wheel but try rocking it in and out with a bit more effort, but not enough to move the steering linkage. That could demonstrate free play from wear in the tie-rod ends or ball joints. If you're not sure where the free play is, pry up on the bottom of the tire and watch the ball joint to see if it has free play1/4 in. is a lot.

To check a tie-rod end joint for looseness, try to flex it by hand. A good tie-rod end should feel snug, but not immobile or stiff.

On rack-and-pinion steering, it's a good idea to check the tie rods' inner sockets. They're covered by the steering rack boots, but you can squeeze the boots to hold the inner joint. Jack up the front end to take the weight off the front wheels. Have a friend slowly turn the steering wheel a partial turn to each side, while you feel for looseness.

Just because you can't feel a lot of free play or "wobble" in a wheel doesn't mean there isn't enough to cause vibration. It doesn't take a lot to be responsible for objectionable vibration at speeds of 60 to 70 mph and above any deviation from a truly circular spin is called runout. It can be vertical (up-down) or horizontal (in-out).

The only practical way to check for runoutfront or rearis with a dial indicator, another tool you can rent at many parts stores. There are several different checks to make to pinpoint the source of the runout.

Mount the indicator on something heavy that won't move, such as an anchor plate or wheel hub/knuckle. Position the plunger for the specific runout check. Example: For a radial runout test, rest it against a good tire tread groove. Slowly turn the tire and measure the amount of runout, ignoring jumps in the plunger that result from the shape of the tread or minor imperfections in it. If there are factory specifications for runout, use those.

If you don't have specs, see if the runout is about .050 to .060 in. this measurement is considered rule of thumb. The tire almost surely isn't the issue, although there is precision equipment that can check a tire for heavy spots.

To isolate the source of the runout, check it at the wheel with the plunger on an underside horizontal surface. Ignore minor imperfections in the wheel finish (paint, weld, tiny dings) that cause the plunger to jump instantaneously. If the runout is over .045 in., the wheel should be replaced.

If radial runout isn't bad, check lateral runout with the plunger against the sidewall, even if the in-out rocking didn't show anything. Obviously, ignore any plunger movement from raised lettering, etc. If the runout is over .045 in., it's too much. Here again, isolate the runout by checking at the wheel with the plunger against a vertical surface. The rule-of-thumb specs are the same as for radial runout.

When the runout at the wheel is excessive, a new wheel normally is the answer, but not always. Remove the wheel and check runout on the wheel hub. Making a lateral runout check is an obvious procedure because there's a hub face against which you can rest the plunger.

For a radial check, it may be more difficult if the top surface of the hub isn't reasonably smooth because you have to use the threaded edges of the studs, and, typically, there are only four or five of those studs. So it does take some careful measuring to see if there's a significant amount. You have to look for the peak reading at each stud to be sure you're measuring at the outermost point. Unless almost all the radial runout is in the bolt circle, and that amount is at least .030 in., go for a new wheel. Replacing the hub and bearing on a front-drive is not a quick and easy job.

It can take a couple of hours to check out the possible causes of high-speed vibration, and you may be tempted to take the car in for wheel alignment to see if that helps before you spend time on all these other things. Sorry. Unless there's some evidence of wheel misalignment (such as irregular tire wear), a wheel alignment is not going to help at all. In fact, until you first isolate and correct the cause of the vibration, alignment would be a waste of time and money.

Additional Info.

I have found several cases of front end vibration due to worn shocks and/or struts. These two items soak up vibrations caused by oscillation in tires. No tire/wheel combination is perfectly balanced. If he shock/strut is not optimal in it's functions, these vibrations are transmitted to the steering wheel. Also when wheels and tires are balanced, they are only balanced to themselves. Out of round brake rotors and even slight loose ball joints may cause the oroblem. If you front tires are the same as your rear tire (which they should be) swap them and see if the problem still exists. If it does, it is not a problem with the tire/wheel combination. If it does remedy the problem, have the tires balanced at a different shop first (worth the few bucks).

Additional Info:

It also matters whether the balance done was single-plane or dual-plane (whether the balance technician eliminated only the 'up and down' element of the tire/wheel imbalance, or the 'side to side' element as well. It is common for many shops to use single-plane balancing on alloy and custom rims so there are no 'unsightly' wheel weights on the outer side of the wheel.

A good balancing technician can use a computerized balancer to minimize the amount of weight needed to balance a wheel. However, many shops do not do this because it requires extra work (tire/wheel must be broken down and shifted to accomplish this), and often the technicians at big-box stores and similar venues do not even know how.

There is a lot of very good, very detailed information in the responses above. Just be assertive while checking the tire/wheel balance element of your problem - you are the customer and any shop that won't take the time to address your questions is not a shop to which you want to take your business. ASK them to do a dual-plane balance on your wheels, and if the amount of required weight is excessive, to use their balancer's program to minimize the weight.