Trim height is a pre-determined measurement relating to vehicle ride height. Incorrect trim heights can cause bottoming out over bumps, damage to the suspension components and symptoms similar to wheel alignment problems. Check the trim heights when diagnosing suspension concerns and before checking the wheel alignment.
Perform the following before measuring the trim heights:
The C height dimension measurement determines the proper ride height for the front end of the vehicle. Vehicles without torsion bars have no adjustment and could require replacement of suspension components.
The B height dimension measurement determines if the front axle is bent.
Check the suspension and steering components for any binding conditions.
Measure from the axle center line of each front wheel to the bottom of the axle beam to obtain the B height measurement for the front axle.
The C height dimension measurement determines the proper rear end ride height. There is no adjustment procedure. Repair may require replacement of suspension components.
• | Sagging front suspension--Refer to Leaf Springs Replacement . |
• | Sagging rear springs--Refer to Leaf Spring Replacement or Diagnostic Starting Point - Air Suspension . |
• | Improper tire inflation |
• | Improper weight distribution |
• | Collision damage |
The tandem axle must be measured in three locations to be sure of proper ride height. B, C, E height dimension measurements determine the proper rear end ride height. There is no adjustment procedure. Repair may require replacement of suspension components.
Measure the E height by measuring the distance between the center line of front axle of the tandem to bottom inside of frame rail.
Measure the B height by measuring the distance between the center line of rear axle of the tandem to bottom inside of frame rail.
• | Sagging front suspension--Refer to Leaf Springs Replacement . |
• | Sagging rear springs--Refer to Leaf Spring Replacement or Diagnostic Starting Point - Air Suspension . |
• | Improper tire inflation--Refer to Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label . |
• | Improper weight distribution |
• | Collision damage |