Leaf Spring Replacement Tandem Axle RT-400 Type

1. The RT-400 suspensions use through bolts instead of U-bolts in order to secure the spring to the spring seat.
2. Set the parking brake.
3. Block the front wheels.
4. Raise the vehicle frame using a suitable lifting device.
5. Support the frame forward of the rear axle.
6. Remove the wheel assemblies from both rear axles. Refer to Tire and Wheel Removal and Installation in Tire and Wheels.
7. If you removed the wheel assemblies, support the axles high enough in order to take the weight off of the spring assembly.
8. Remove the following components:

•	The saddle cap nuts

•	The washers

•	The saddle caps

9. Remove the following components:

•	The saddle bolt nuts

•	The washers

•	The saddle bolts

10. Loosen the jam nuts on the top pad set screw.
11. Remove the top pad.

11.1.

Loosen the set screw.

11.2.

Lift the pad and slide the pad out from the top of the spring assembly.

12. Remove the following components:

•	The rebound bolt nut

•	The washer

•

The bolt

13. Remove the following components:

•	The eye pin clamp bolt nut

•	The washer

•

The bolt

14. Remove the lubrication fitting from the inner end of the spring eye pin.
15. Remove the spring eye pin.
16. Remove the spring assembly using a suitable hoist.
17. Raise the vehicle frame until the shock brackets clear the spring.
18. Clean the following components:

•	The spring eye bushing

•	The spring eye pin

•	The spring leaves

19. Inspect the lubricant passages in the spring eye pin.
20. Inspect the spring eye pin for looseness.
21. Inspect the spring and spring bracket for looseness. Insert a clean eye bushing into the spring and into the spring bracket. If excessive looseness occurs, replace the eye bolt, the bushings or the spring bracket.
22. Inspect the spring leaves for cracks or breaks.
23. Replace the first or second main leaves.
24. If other leaves are broken, replace the complete spring assembly.
25. Inspect the rebound clips for cracks or breaks.

1. Install the spring assembly on the spring saddle using a suitable device.

•	Ensure that the head of the center bolt is in the saddle clearance hole.

•	Ensure that the spring ends are in position in the brackets.

2. Install the top pad (6).
3. Install the spring eye pin.



4. Lower the frame. Align the spring eye and the brackets.
5. Apply a thin coat of chassis lubricant to the eye pin and the spring eye bushing.
6. Insert the eye pin through the bracket and the spring eye bushing. Align the milled flat with the eye bolt in the bracket.
7. Use a hammer in order to drive the eye pin from the other side.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

8. Install the following components:

•	The clamp bolt

•	The washer

•

The nut

Tighten
Tighten the eye pin clamp nut to 75 N·m (55 lb ft).

9. Install the lubrication fitting in the inner end of the eye pin.
10. Install the following components:

•	The rebound bolt

•	The washer

•

The nut

Tighten
Tighten the rebound nut to 75 N·m (55 lb ft).

Important : Do not tighten the fasteners yet.

11. Install the following components:

•	The saddle top pad bolts

•	The washers

•

The nuts

Important: Assemble all components and remove all jack stands and lifting devices before the final tightening of the suspension components.

12. Install the setscrews and jam nuts.

Tighten

•	Tighten the jam nuts until the spring washers are flat.

•	Tighten the setscrews to 170 N·m (125 lb ft).

Important: In order to properly tighten the saddle top pad bolts, torque the bolts progressively using the following steps.

13. Tighten the saddle top pad bolts.

Tighten

1. Tighten the saddle top pad bolts to 130 N·m (95 lb ft) in sequence.
2. Tighten the saddle top pad bolts to 260 N·m (190 lb ft) in sequence.
3. Tighten the saddle top pad bolts to 385 N·m (285 lb ft) in sequence.
14. Install the saddle cap studs.

Tighten
Tighten the saddle cap stud to 81 N·m (60 lb ft). Use the two nut method.

15. Install the following components:

•	The saddle caps

•	The washers

•

The nuts

Tighten
Tighten the saddle cap nut to 340 N·m (250 lb ft) after the axle is in normal operating position.

•	Install the wheel assemblies from both rear axles. Refer to Tire and Wheel Removal and Installation in Tire and Wheels.

Leaf Spring Replacement Single Axle

1. Set the parking brake.
2. Block the front wheels.
3. Raise the vehicle frame using a suitable lifting device in order to remove the weight of the vehicle from the spring assembly.

Support the frame forward of the rear axle.

4. Remove the rear dual wheel assembly, if necessary. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
5. Remove the following components:

•	The rebound nut

•	The washer

•

The bolt

6. Remove the shock absorber. Refer to Shock Absorber Replacement .
7. Remove the U-bolt nuts and washers.
8. Remove the following components:

•	The U-bolt anchor plate

•	The shock absorber bracket

9. Remove the U-bolts.
10. Remove the seat
11. Lower the axle slightly.
12. Remove the following components:

•	The eye bolt nut

•	The washer

•	The eye bolt

13. Support and raise the vehicle using a suitable lifting device in order to provide clearance between the spring assembly and the hanger bracket.

Support the frame forward of the rear axle.

14. Remove the following components:

•	The auxiliary spring bolt

•	The spacer

•	U-bolt spacer

15. Remove the spring assembly using a suitable hoist.

1. Install the spring assembly onto the axle pad or axle stabilizer/spring seat, if equipped, using a suitable hoist.
2. Install the following components:

•	The auxiliary spring

•	The U-bolt spacer

•	The spacers

•

The bolt

3. Install the U-bolt spacer over the center bolt.
4. Install the U-bolts into the spacer grooves.
5. Install the U-bolt anchor plate (1) and seat.
6. Install the shock absorber bracket or stabilizer shaft/spring seat, if equipped.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Important: In order to properly tighten the U-bolt nuts, torque the nuts progressively as outlined below.

7. On 15,000 lb axles, install the 20 mm U-bolt nuts (2) and the washers.

Tighten

1. Tighten the U-bolt nuts to 100 N·m (74 lb ft) in sequence.
2. Tighten the U-bolt nuts to 250 N·m (184 lb ft) in sequence.
3. Tighten the U-bolt nuts to 388 N·m (287 lb ft) in sequence.
8. On 19,000-26,000 lb axles, install the 20 mm U-bolt nuts (2) and the washers.

Tighten

1. Tighten the U-bolt nuts to 150 N·m (111 lb ft) in sequence.
2. Tighten the U-bolt nuts to 275 N·m (203 lb ft) in sequence.
3. Tighten the U-bolt nuts to 437 N·m (344 lb ft) in sequence.
9. Install the following components:

•	The spring eye bolt nut

•	The washer

•	The eye bolt

Tighten
Tighten the spring front eye bolt to 415 N·m (305 lb ft).

10. Install the shock absorber. Refer to Shock Absorber Replacement .

Tighten
Tighten the lower shock absorber nut to 61 N·m (45 lb ft).

11. Lower the frame until the hangers touch the surface of the spring eye.



12. For tapered leaf springs, install the following components:

•	The rear spring hanger rebound bolt

Tighten
Tighten the bolt to 415 N·m (305 lb ft).

•	The washer

•

The nut

13. For multileaf springs, install the rear spring hanger bolt.

Tighten
Tighten the bolt. Ensure that a minimum of 84.07 mm (3.36 in) is between the ears (1) of the rear spring hanger.