Curb Height Measurement

STANDARD PROCEDURE - CURB HEIGHT MEASUREMENT
On this vehicle, the alignment specifications must be checked and all alignment adjustments made with the vehicle at its required curb height specification.
1. Position the vehicle on a flat, level surface preferably a wheel alignment rack.

NOTE: Inflation pressure of the tires will adversely affect the curb height measurement of the vehicle. Over inflated tires will raise the curb height and under inflated tires will lower the curb height. Be sure the tires are inflated to the correct pressure. Refer to the tire placard on the drivers door of the vehicle.

2. Check all tires for proper inflation. The tires are to be inflated to the recommended pressure. All tires are to be the same size as original equipment.
3. Verify the fuel tank is full and that there is no passenger or luggage compartment load.
4. Follow the procedures below to measure and if necessary, correct curb height.

FRONT CURB HEIGHT MEASUREMENT





NOTE: The bar being used to measure the front curb height must be sitting on the same surface as the front tires such as the alignment rack turntables. If the bar is not placed on the same surface as the tires it will affect the accuracy of the curb height measurement. Also, the bar must be stiff enough so it will not bend when spanning the alignment rack.

1. Place the metal bar across the alignment rack. The metal bar must be placed on the same surface of the alignment rack as the tires are sitting on such as the turn tables for the front tires.
2. Using a ruler, measure the curb height of the vehicle. The curb height measurement is taken from the bottom surface of the frame crossmember to the bottom edge of the metal bar. The curb height measurement must be taken on both the left and the right side of the vehicle. The location on the vehicle to measure front curb height is opposite each steering gear mounting bracket on the front crossmember of the frame. Refer to curb height specifications.

REAR CURB HEIGHT MEASUREMENT





NOTE: The bar being used to measure the vehicle curb height must be sitting on the same surface as the rear tires such as the rear skid plates on the alignment rack. If the bar is not placed on the same surface as the tires it will affect the accuracy of the curb height measurement. Also, the bar must be stiff enough so it will not bend when spanning the alignment rack.

1. Place the metal bar across the alignment rack. The metal bar must to be placed on the same surface of the alignment rack as the tires are sitting on such as the skid plates for the rear tires.
2. Using a ruler, measure the rear curb height of the vehicle. The curb height measurement is taken from the bottom surface of the frame rail to the bottom edge of the metal bar. The curb height measurement must be taken next to the Principal Locating Point (PLP) hole on both the left and right side of the vehicle. Refer to curb height specifications.

CURB HEIGHT CORRECTION
If the front and or rear curb height measurements do not meet the dimensions listed in Curb Height Specifications, it may be due to improperly tightened suspension fasteners. If certain suspension component fasteners are tightened when the vehicle is not positioned at curb height, it can result in the curb height of the vehicle being too high or too low. In this case, a suspension bushing may be holding the vehicle up or down. Use the following procedure to verify this possibility.
1. Loosen the attaching bolts for the suspension components listed below:
Front:
- Front lower control arm pivot bolts
- Push rod to front lower control arm bolt
- Front upper control arm cam bolt nuts Do not move adjustment cams.
- Front shock absorber to frame attaching bolts
Rear:
- Rear lower control arm pivot bolts
- Rear shock absorber to lower control arm bushing bolt
- Rear shock absorber to frame bolt
- Rear trailing link to frame and knuckle attaching bolt
- Rear lateral links to frame and knuckle attaching bolts
2. Jounce the front and rear of the vehicle with the attaching bolts loosened to allow the bushings to relieve any torque remaining in the rubber and let the springs adjust the height of the vehicle. When jouncing the vehicle, the vehicle must be released at the bottom of the jounce cycle. This will ensure the vehicle's suspension will raise the vehicle to the correct curb height at the top of the jounce cycle.
3. Tighten all of the attaching bolts listed above that were loosened to the specified tightening torque.
4. Jounce the front and rear of the vehicle with the attaching bolts tightened to the specified torques. When jouncing the vehicle, the vehicle must be released at the bottom of the jounce cycle. This will ensure the vehicle's suspension will raise the vehicle to the correct curb height at the top of the jounce cycle.
5. Measure the curb height of the vehicle again to see if it is at the required curb height.
6. If the vehicle still does not meet the curb height specifications, inspect the following suspension components for conditions which may cause the vehicle to not meet the curb height specifications.
- Shock absorber assembly mounting bushings.
- Upper and lower control arm mounting bushings.
- Shock absorber springs.
- Frame damage to vehicle which affects mounting location of a suspension component.
- Front and rear sway bar.
- Inspect all suspension components for signs of damage which may have been a component.
7. If the inspection does not determine why the vehicle is not meeting the front or rear curb height specification, the shock absorber springs should be replaced to correct the curb height of the vehicle. After replacing the springs on the shock absorbers, the vehicle must be at the correct curb height before tightening and torquing the shock absorber mounting bolts.





CURB HEIGHT SPECIFICATIONS