Dorman 929-110 Leaf Spring Instruction Manual

1. Product Overview

The Dorman 929-110 Leaf Spring is a direct replacement component designed to restore proper suspension performance and vehicle stability. Leaf springs are crucial for supporting the weight and payload of a vehicle or trailer, contributing significantly to ride comfort and handling.

Key Features:

• Direct Replacement: Engineered to match the fit and function of original leaf springs on specified vehicles.
• Reliable Solution: Effectively replaces leaf springs that are damaged due to overloading, collision, cracking, or corrosion.
• Durable Construction: Manufactured from quality materials to meet strict specifications, ensuring reliable performance and extended service life.

Image 1: Dorman 929-110 Leaf Spring, a multi-leaf spring assembly with eyelets at each end.

2. Vehicle Compatibility

This Dorman 929-110 Leaf Spring is compatible with the following vehicle models and years:

• Chevrolet Express 1500: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014
• GMC Savana 1500: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014

To ensure precise fitment for your specific vehicle, it is recommended to verify compatibility using a vehicle fitment tool or by cross-referencing OEM part numbers.

3. Installation Preparation & Measurement

Accurate measurement of your existing leaf spring is critical for selecting the correct replacement, especially if the original equipment (OE) number is unavailable or if you cannot use vehicle application data. Measurements should be taken from a relaxed spring that has been removed from the vehicle.

How to Measure Leaf Springs:

1. Length Axis 1 (A) - Short Side: Measure along the leaf surface from the center of the front eyelet to the center of the spring arch.
2. Length Axis 2 (B) - Long Side: Measure along the leaf surface from the center of the rear eyelet to the center of the spring arch.
3. Arch Length (C): Measure the vertical distance from the top of the spring arch to a straight line connecting the centers of both eyelets.
4. Pack Thickness (D): Measure the total thickness of the leaf spring pack at its thickest point, typically near the center.
5. Width (E): Measure the width of the leaf spring pack.

Image 2: Detailed diagram for measuring leaf springs, including key dimensions.

Image 3: Close-up view of a leaf spring eyelet, showing the integrated bushing.

4. Installation Guidelines

Installation of leaf springs typically requires specialized tools and mechanical knowledge. It is recommended that installation be performed by a qualified automotive technician.

General Steps (Consult a service manual for your specific vehicle):

1. Safety First: Ensure the vehicle is securely lifted and supported on jack stands. Disconnect the battery if necessary.
2. Remove Wheels: Remove the rear wheels to access the suspension components.
3. Support Axle: Use a floor jack to support the rear axle assembly.
4. Disconnect Components: Carefully disconnect shock absorbers, U-bolts, and any other components attached to the leaf spring.
5. Remove Old Spring: Unbolt the leaf spring from its front and rear hangers.
6. Install New Spring: Position the new Dorman 929-110 Leaf Spring and secure it to the hangers. Do not fully tighten bolts until the vehicle is at ride height.
7. Reassemble: Reattach U-bolts, shock absorbers, and other components.
8. Lower Vehicle: Carefully lower the vehicle to the ground.
9. Final Tightening: With the vehicle at normal ride height, fully tighten all leaf spring bolts to the manufacturer's specified torque.
10. Test Drive: Perform a short test drive to ensure proper function and check for any unusual noises or handling characteristics.

5. Operation

Leaf springs are a fundamental component of a vehicle's suspension system, designed to support the vehicle's weight, absorb road shocks, and maintain tire contact with the road surface. They work by flexing and returning to their original shape, distributing loads and providing a stable ride. Proper operation ensures vehicle control, passenger comfort, and the ability to carry intended loads.

6. Maintenance

Regular inspection and maintenance can extend the life of your leaf springs and ensure continued safe operation.

Maintenance Tips:

• Visual Inspection: Periodically inspect leaf springs for signs of damage such as cracks, rust, broken leaves, or worn bushings.
• Check U-Bolts: Ensure U-bolts are tight and free from corrosion. Loose U-bolts can lead to premature spring failure.
• Lubrication: Some leaf springs may benefit from lubrication between leaves, depending on their design. Consult your vehicle's service manual.
• Avoid Overloading: Do not exceed the vehicle's Gross Vehicle Weight Rating (GVWR) or Gross Axle Weight Rating (GAWR), as overloading can severely damage leaf springs.
• Cleanliness: Keep springs free from excessive dirt, salt, and debris, which can accelerate corrosion.

7. Troubleshooting

If you experience issues with your vehicle's suspension after leaf spring replacement or during normal operation, consider the following common problems and potential solutions:

Common Issues:

• Sagging Suspension: This can indicate worn or fatigued leaf springs, or consistent overloading. Inspect for broken leaves or permanent deformation.
• Excessive Bouncing/Rough Ride: While often related to shock absorbers, worn leaf springs can also contribute to poor ride quality.
• Squeaking/Creaking Noises: May indicate dry or worn bushings, or friction between leaves. Lubrication or bushing replacement may be necessary.
• Uneven Ride Height: Could be due to a damaged spring on one side or improper installation.

For persistent or severe issues, consult a professional automotive technician.

8. Specifications

9. Important Safety Information

Working with vehicle suspension components can be hazardous. Always follow proper safety procedures to prevent injury or damage to the vehicle.

• Always wear appropriate personal protective equipment (PPE), including safety glasses and gloves.
• Ensure the vehicle is properly supported on a level surface using sturdy jack stands before beginning any work. Never rely solely on a jack.
• Be aware of stored energy in suspension components. Use spring compressors or other specialized tools as required and exercise extreme caution.
• Refer to your vehicle's specific service manual for detailed instructions and torque specifications.

10. Warranty and Support

For information regarding the warranty coverage for your Dorman 929-110 Leaf Spring, please refer to the documentation provided with your purchase or visit the official Dorman website. For technical support or further assistance, contact Dorman customer service or your product retailer.