Design Height Measurement
DESIGN HEIGHT MEASUREMENT
NOTE: This procedure is designed to be performed with original factory wheels installed. Non-OEM wheels may cause inaccurate measurement.
1. Verify vehicle fuel tank is full of fuel. If tank is not full of fuel, reduction in weight will affect height of vehicle and design height measurement.
2. Remove any load within passenger and luggage compartments that is not factory equipment.
3. Place vehicle on wheel alignment rack or drive-on lift per equipment manufacturer's recommendations.
4. Check all tires for proper inflation pressure and adjust as necessary.
NOTE: In order to get an accurate rear height measurement it is necessary to remove the belly pan.
5. Remove belly pan from frame. Belly Pan - Removal
6. Place Height Gage Extension (3), Special Tool 8997, over smaller end of one of two Suspension Height Gages (1), Special Tool 6914, aligning adapter locating pin with notch in gage end.
7. Tighten adapter thumb screw (2).
NOTE: The height gage with the adapter attached to it is now the height gage to be used on the front suspension.
NOTE: In order to achieve an accurate vehicle height measurement, it is absolutely necessary to position the height gages on the inner rim flange at the very bottom of the wheel. That way the top surface of each gage is parallel front-to-rear with bottom surface of the frame rails.
8. Install front Suspension Height Gage (1) with Extension on vehicle. Ensure that gage is correctly attached to inner rim flange at very base of each wheel.
9. Install rear Suspension Height Gage (1) on vehicle. Ensure that gage is correctly attached to inner rim flange at very base of each wheel.
CAUTION: Only apply weight to seat cushions as described in STEP 10. Do not over-ballast the vehicle. If vehicle is over-ballasted, the design height will be incorrect.
10. Add 150 pounds ballast weight (2, 3) to each seat cushion (1, 4) of vehicle (300 pounds total) to lower vehicle to specified design height.
11. Jounce vehicle several times, each time paying special attention to release vehicle at very bottom of jounce cycle. This is very important in allowing suspension to settle to correct height.
12. Measure and record vehicle's front design height. Measure distance (2) between top of Suspension Height Gage (4) and each frame rail at forward edge of Gage. This is the nearest point to the Principle Locating Point (PLP) hole (1).
13. Measure and record vehicle's rear design height. Measure distance (1) between top of Suspension Height Gage (4) and each frame rail at forward edge of Gage. This is the nearest point to the PLP hole (2).
14. Compare recorded measurements to specifications. Specifications
15. If recorded height is higher than specifications, jounce vehicle and remeasure. Before remeasuring design height, be sure to jounce the vehicle as described in STEP 11. If still above specifications, one or more of following rubber bushing mounted suspension components may not be properly positioned and tightened. Loosen either front, rear or all components as necessary at the following locations allowing suspension to enter specified design height.
- Front and rear lower control arm to frame bracket cam adjustment bolts.
- Front and rear upper control arm to frame bracket mounting bolts.
- Front and rear shock assembly to frame bracket mounting bolts.
- Front and rear shock assembly to lower control arm mounting bolts.
NOTE: When loosening the lower control arm mounting bolts, be sure the alignment adjustment cams do not turn. The cams must stay in their original position so the alignment of the vehicle is not affected.
NOTE: The mounting bolts must be loosened enough to allow the suspension of the vehicle to move without loading (twisting) the rubber insert of the isolator bushings.
16. Tighten previously loosened mounting bolts to specified torque values. Front Suspension Rear Suspension
- Front and rear lower control arm to frame bracket cam adjustment bolts and nuts.
- Front upper control arm to frame bracket mounting bolts.
- Rear upper control arm to frame bracket mounting bolts.
- Front and rear shock assembly to frame bracket mounting bolts.
- Front shock assembly to lower control arm mounting bolts.
- Rear shock assembly to lower control arm mounting bolts.
17. Remove Suspension Height Gages from vehicle.
18. If wheel alignment is to be performed, proceed at this point. Service and Repair
19. Install belly pan. Belly Pan - Installation
20. Remove ballast weight from vehicle, allowing vehicle to return to curb height.