Jeep JK Wrangler Front End Alignment

Jeep JK Wrangler Front End Alignment

A common symptom of installing a lift kit on a Jeep JK Wrangler is misalignment of the wheels and axles.  Increasing the gap between the axle and the chassis (the goal of a lift kit) has a lot of effects on how the Jeep handles, steers, and rides.  Common lift kits are simply new shocks, coils, and maybe sway bar links – they leave the drag link, control arms, and track bars completely unchanged.  Since those three components connect the axle to the chassis and the gap between the axle and chassis increases, obviously something has to give.  So here is some information that will help you to even out your axle and wheel alignments after installing a lift kit.

Alignment Definitions

Straight from the JK service manual are these definitions.  See the diagram below the text definitions for a visual on each type:

CASTER is the forward or rearward tilt of the steering knuckle from vertical. Tilting the top of the knuckle rearward provides positive caster. Tilting the top of the knuckle forward provides negative caster. Caster is a directional stability angle. This angle enables the front wheels to return to a straight ahead position after turns.

CAMBER is the inward or outward tilt of the wheel relative to the center of the vehicle. Tilting the top of the wheel inward provides negative camber. Tilting the top of the wheel outward provides positive camber. Incorrect camber will cause wear on the inside or outside edge of the tire. The angle is not adjustable, damaged component(s) must be replaced to correct the camber angle.

WHEEL TOE POSITION is the difference between the leading inside edges and trailing inside edges of the front tires. Incorrect wheel toe position is the most common cause of unstable steering and uneven tire wear. The wheel toe position is the final front wheel alignment adjustment.

STEERING AXIS INCLINATION ANGLE is measured in degrees and is the angle that the steering knuckles are tilted. The inclination angle has a fixed relationship with the camber angle. It will not change except when a spindle or ball stud is damaged or bent. The angle is not adjustable, damaged component(s) must be replaced to correct the steering axis inclination angle.

THRUST ANGLE is the angle of the rear axle relative to the centerline of the vehicle. Incorrect thrust angle can cause off-center steering and excessive tire wear. This angle is not adjustable, damaged component(s) must be replaced to correct the thrust angle.

Jeep JK Wrangler Front End Alignment

Recentering The Steering Wheel

An uncentered steering wheel is caused by changing the distance between the axle and the body of the vehicle.  This happens, obviously, when a lift is installed.  The drag link which connects the pitman arm to the steering knuckle on the axle stays the same length while the distance it is required to span increases so something has to give.  The pitman arm swinging to the right and taking the steering wheel with it is the common cause of the steering wheel not being centered after a lift.  Adjusting the drag link to recenter the steering wheel is the best option to correct the steering wheel alignment.  While this may seem like a difficult job, it’s actually something very easy to do.

You will need a 15 mm socket and ratchet to match or equivalent.

  1. Park your Jeep on a flat surface, engage the parking brake and/or chock the wheels, and attempt to center the wheels as best you can.  You can use a long and straight piece of wood or other straight material such as metal pipe, and run it along the side walls of the front and rear tires on one side of the Jeep to check the centering on the front tires:  If the sidewalls make contact with the piece of wood in 4 places, the front tires are as straight as they can be.
  2. Loosen the two 15 mm nuts that secure the turnbuckle on the drag link.
  3. Once loose enough to turn by hand, rotate the turnbuckle to expand or retract the drag link.  Turning it up (towards the front of the Jeep) will turn the steering wheel to the left and doing the opposite will turn the steering wheel to the right.
  4. Once the steering wheel is as close to center as you can adjust, tighten both 15 mm nuts on the turnbuckle.
  5. Take the Jeep out for a spin around the block to test the steering wheel alignment and make adjustments as necessary.  This may take you a few rounds to get it just perfect.

Align the front tires by setting the Toe In

This is the actual alignment that most people think about when they hear front end alignment.  On the JK, Toe In is not affected by installing lift kits.  Toe In, however, can be affected by installing a new tie rod or damaging a tie rod by bending it.  It doesn’t take much of a bend to drastically affect the toe in.  Having an improper toe in can cause major tire wear problems, greatly reducing the life of your tires.  See this great video that explains Toe In by Engineering Explained:

You will need the following items to adjust your Toe In:

  • Measuring tape
  • 15mm socket and ratchet to match, or equivalent
  • Chalk (optional)
  • Assistant (optional)
  1. Park your Jeep on a flat surface, engage the parking brake and/or chock the wheels, and attempt to center the wheels as best you can.
  2. Measure to the center of the tread of the front tires, front and back of the front tire.  You are trying to find the center line of the tread.  Mark this spots with chalk.  These spots will be your points of measurement.
  3. With your optional assistant helping, use the measuring tape to measure the distance between the left and right front spots and the left and right rear spots.  The difference is your toe in distance (if the front distance is longer than the rear, this would be “toe out”).
  4. Start your motor and turn your steering wheel all the way to the right and then left and then center the steering wheel as close to center as you can so that when you release the steering wheel it is resting in the center.
  5. Using the 15 mm socket or equivalent, loosen the 15 mm nut on the clamp that secures the adjuster on the tie rod found on the driver’s side (stock tie rod).
  6. Turn the adjuster by hand to make your toe in measure 1/16th of an inch.  That is, the measurement of the distance between the front spots is 1/16th of an inch shorter than the distance between the two rear spots.  You will need to measure both as you make adjustments as the measurements of both will change as you make the adjustments:  Retracting the tie rod will reduce the measurement between the front spots and increase the measurement between the rear spots.
  7. Once your Jeep is sitting at 1/16th of an inch of toe in, carefully tighten the 15 mm nut on the adjuster clamp to 45 ft/lbs of torque while ensuring the tie rod doesn’t move while doing so.

Re-centering The Front Axle

Sometimes known as centering the thrust angle.

Installing a lift on a Jeep Wrangler JK will shift the axles off the center line of the entire vehicle.  The track bars are the primary culprit for this.  The track bar connects the frame of the jeep to the axle and is designed to keep the axles from floating left or right under the jeep.  The front track bar swings down and to the driver’s side and the rear track bar swings down and to the passenger’s side.  Lifting the vehicle will cause the track bar to swing down and to its swing direction, taking the axle with it.

You can install a track bar relocation bracket that matches the amount of the lift you installed.  You’ll need a bracket in the front and rear to align your thrust angle properly.  Typical front track bar relocation brackets attach to the axle and raise the axle-side mount of the track bar and typical rear track bar relocation brackets are drop brackets that mount to the chassis-side mount of the track bar.

The other alternative is installing adjustable track bars.  This is preferred as you can really dial in and precisely adjust them whereas the relocation brackets are hard set at a certain drop amount.  Over time, the coils in your lift may start to sag causing a set of relocation brackets that were perfect to be not-so-perfect.

This guide assumes you have adjustable track bars.  You will need the following tools to recenter your front axle:

  • Measuring Tape
  • Carpenter’s Level
  • 21 mm socket and ratchet or equivalent (You may need a 2 or 4 inch extension)
  • Crescent wrench
  • Small Ruler (optional – you can use a measuring tape instead)
  • Assistant (optional)
  1. Measure the amount of axle offset you have.  Do this by placing the carpenter’s level vertical against the side wall of your front axle aligned with the center of the wheel.  Once you are certain that the carpenter’s level is level, use your tape measure to measure the distance between a predetermined point on the chassis/body of the jeep, such as your fender flare, and the inside edge of the carpenter’s level.  Measure like this again on the other tire.  Then calculate the offset.  If your passenger side tire sticks out 2 inches and the driver’s side sticks out 4 inches, then you have a driver side offset of 1 inch.  You would need to extend your front track bar by roughly 1 inch.  To calculate, subtract the two measurements and divide by 2.  Your offset direction is the direction the axle sits further out on.
  2. Remove the bolt that secures the front track bar to the axle mount using a 21 mm socket.  There is a flag nut on the far side so you won’t need a second tool.
  3. Break the tension on the jam nut on the track bar so that you can turn it by hand.  Continue turning it by hand until it touches the track bar end.
  4. Measure the gap between the inside of the jam nut and the track bar edge.  This is your baseline measurement.
  5. Rotate the track bar end in or out, depending on the offset you need to adjust for calculated in step #1.  If your baseline measurement was 1.5 inches and you need to extend your trackbar 1 inch to make up for a driver’s side offset you would need to extend the track bar until the new measurement is roughly 2.5 inches.
  6. Once satisfied with the adjustment, tighten the jam nut back against the track bar edge using a crescent wrench.
  7. You will need to turn the steering wheel slightly to get the track bar to line up with its axle mount.  It is advised to do this with the engine off.
  8. Once the track bar lines up with its axle mount, use the 21 mm socket to tighten the bolt to 125 ft/lbs of torque.
  9. Take your jeep around the block to settle the adjustments out.  Remeasure the offsets and readjust as necessary until the offset is 0 inches!

Setting Caster

Another symptom of a lift kit install is a wandering sensation, especially at highway speeds.  The Jeep won’t feel like it wants to stay on a straight path.  The stock Jeep caster is positive 4.2 degrees.  Installing a lift kit will reduce the caster angle and will make the steering feel neutral – in that when you release the steering wheel it doesn’t want to straighten out as much as it used to.  Too much positive caster will cause the joints in the drive shaft to bind up and cause vibrations in the drive line.  The video below by Engineering Explained does a great job explaining the effect of caster.

This guide assumes that you have adjustable control arms.  Adjustable upper and lower control arms are preferred for maximum configuration but you can get away with either a set of adjustable upper or a set of adjustable lower control arms.  Adjustable lower control arms are more expensive but easier to adjust due to their accessibility from where they are installed on the Jeep.  To set caster, you will need the following tools:

  • Jack Stands  (Safety first.  Seriously, buy a set.  You don’t need anything insane… the average 2 door JK weighs roughly 4,600 pounds.)
  • Chock Blocks
  • Floor Jack, scissor jack, bottle jack, or a jack of some sort that can lift from under the axle.
  • Crescent Wrench
  • Angle Finder
  • 18 mm socket with ratchet or equivalent
  • Assistant (optional)
  1. Park your jeep on a level spot, as level as possible and chock the rear tires.  Put the angle finder on the ground in the same orientation that you intend to make measurements off of your Jeep. that you have parked at and note any measurement that is not 0 degrees.  This will be your baseline angle offset.
  2. Place the angle finder on your driver’s side top ball joint in the same orientation that you measured the ground off of. and measure the angle.  This is your Jeep’s current caster angle relative to your baseline angle offset that you measured off the ground in step #1.  Subtract your baseline angle offset from the measurement from your ball joint to get the true caster angle.
  3. If your measurement is not 4.2 degrees positive (leaning towards the back of the Jeep) then use a crescent wrench to loosen the jam nuts on your adjustable control arms.
  4. Remove the bolt and nut securing the passenger side adjustable control arm to the axle mount using the 18 mm socket and ratchet or equivalent.  Pull the control arm out of the mount.
  5. Turn the control arm end to adjust the length.  If it is an upper control arm you will need to shorten it to increase the amount of caster and lengthen it to decrease the amount of caster.  If it is a lower control arm you will need to lengthen it to increase the amount of caster and shorten it to decrease the amount of caster.  COUNT HOW MANY ROTATIONS YOU MAKE because you will need to apply exactly that many rotations to the other side!
  6. Place the end of the control arm in the axle mount as best you can.  It will likely not line up at this point.  If your axle needs to rotate counter-clockwise from the perspective of the passenger side, place your floor jack or equivalent under the pinion base for the lower control arm and gently raise the axle until the holes line up.  If your axle needs to rotate clockwise, place your floor jack as close to the passenger side tie rod end/joint as possible and gently lift until the control arm end lines up with the axle mount.
  7. Loosely secure the control arm end with the bolt and nut.  DO NOT TIGHTEN yet.  Leave it loose.
  8. Repeat steps 4, 5, 6, and 7 with the driver side control arm.  For the sake of clarity, if you adjusted the length of the passenger side upper control arm, you must adjust the driver side upper control arm!
  9. Recheck your caster angle once you have adjusted both sides of the upper/lower control arms.  If satisfied, tighten the nuts and bolts on the control arm mounts to 75 ft/lbs of torque.
  10. Tighten the jam nuts on the adjustable control arms.