1999 4Runner - front bushings replacement

Hey Jennifer, sounds like you may need some front suspension/steering components replaced..shaking, shimmying, ..is it getting harder to make it stay in a straight line?.. Find a QUALIFIED professional (OR TWO) and get a SECOND OPINION ALSO!!
Check the tires, wheels, front hubs, etc..the QUALIFIED Pro WILL do this!! Good luck..

Shakes? Not very specific. It could be a loose wheel, wheel out of balance, the balance weights may have come off one or more wheel rims (check for the marks on the rims inner and outer rim where they used to be).
As 1996 model, it could also be worn out suspension bushes.
If you drive on a straight road, and you change from accelerating, to decelerating, does the car skew (turn left or right slightly), this would indicate worn suspension bushes at the rear, acceleration pushes the rear axle forward, deceleration pulls it back, if there is wear (slop) in the rubber bushes, the changing alignment of the rear axle causes the car to "throttle steer". At cruise, this could potentially set up a sort of harmonic motion, and cause a form of "shaking".

like a bad tire or out of round tire..it will make a slight thumping sound while driving..and maybe shake the entire car at low speeds or shake the steering if in front..

you have a rotor that needs turned or replaced,it is out of true from heat,hopefully when pads were put on the caliper slides were cleaned and greased

Have the outer Constant velocity joints been replaced? Are the front control arm rubber bushings in good shape?

1) Take car to non dealer shops willing to give FREE opinion

2) Not likely you have a shock in Driver Front wheel, more likely a strut. Not likely strut needs to be replaced, but strut has a STRUT MOUNT (3 bolts of which can be seen when opening your hood) below this it is connected to STRUT BEARING which below it connects to UPPER SEAT OF STRUT or SPRING INSULATOR, that if loose will rattle. Usually, shops will not tighten, because to tighten is same labor as replace the parts. (Since you already dropped $1000 on ToyotaDealer, ask them to tighten FOR FREE since rattle is still there.)

3) There is a part called a "link," connects strut to stablizer bar, that if bushings are bad will rattle.
4) If stabilizer bar bushing(s) bad, will rattle early on but eventually clunking
5) Bad ball joint or tie rod can rattle as well

Never permit any shop to do expensive work on your car w/o first getting a second opinion somewhere else first. Do not tell second shop that you are there for a second opinion.

Shaking steering wheel at highway speed, no braking
1) Bad tire in front, bad tires in front, verify inflation of tires
2) Wheel alignment may be out
3) Front suspension parts (mentioned several above)

Highway speed to suddenly braking shakes steering wheel
1) Front brake rotors need to be inspected for warping
2) Test calipers on empty road at 40 mph, going straight on very LEVEL ROAD, hit brake pedal SOMEWHAT hard while barely touching steering wheel. If car jerks to one side, instead of braking straight on, you may have a caliper, ABS, or brake fluid pressure regulator off.
3) If brake rotors are warped, may as well replace front brake pads at same moment. Use ceramic.
4) When you drive on VERY LEVEL road on highway, steering wheel must be centered, let go lightly of steering wheel. Did car stay in middle of lane? No? Get a 4-wheel alignment.

Most likely the front tires need to balanced or are worn unevenly. Have all four tires rotated and balanced.

Hi vibration at 60 is normally wheel balance not the alaignment, get the 2 front wheels weighted and balanced, if they are wearing unevenly then it could be suspension bushes,track rod ends.

But most likely the wheels just need balancing only cost about $20 to 30 max

Hope this helps
Regards
Dan

Grab hold off the prop-shaft to see if it is quite solid, it could be a worn UJ. Check the balance weight on the same shaft to ensure it hasn't slipped forward or backwards on the shaft.
Then get wheels checked, they could need re-balancing.

Do a replacement. There is no way to adjust the bar.