List Of Mack Camelback Suspension Issues (Expert Guide)

In this brief article we are going to discuss the different Mack Camelback Suspension problems, what the causes are, and Troubleshooting Tips.

What are the most common Mack Camelback Suspension issues?

The most common Mack Camelback Suspension issues are:

The Camelback Suspension is derived from the traditional “Boggie” suspension that was used in Rail wagons since the early days of rail transport.

In the Cameback’s basic structure consists of

an Inverted Leafspring that is hinged at the frame via a “Trunnion” bushing and Bearing
Leafpsring attached to the axles via Flexible Load Pads housed in a Box bracket with Lateral Spacer Bushings
Axles attached to the frame via Torque rods

The axles move laterally during turning short with a load
The movement would be upto 2 inches
The factors influencing this excessive movement would be the
- Axle Load Pad insulators (top, bottom and lateral)
- Trunnion Bushing
- Leaf Spring Pack U-Bolt Preload
Older models like the 38K did not have the lateral spring load pad insulators (yellow in diagram above). If this was missing then it could be added and will help reduce axle lateral movement
Replacing all suspension bushings with aftermarket Polyurethane equivalent bushings would improve the overall suspension performance under load
Certain aftermarket additions like an additional Lateral control rod would help a great deal.
The lateral rod aftermarket solution would be available as a package with a rod and brackets that bolt on to the frame side rail and the axle housing Top

The Lateral rod connecting the left and right Trunnion brackets gets cracked
This happens over a long usage period and is normal
The reason for it is continuous frame twist loads over a period of time that have got transmitted through the suspension
This sort of failure also means that the entire suspension needs to be checked for wear. Ideally, the suspension is supposed to take up a major portion of road loads before the load is transferred to the frame. But in the case where there is excessive suspension wear, a larger portion of road loads may be taken up by the chassis frame

Depending on the type of application, the leaf springs either wear out faster or slower.
If your truck is applied at a site where is maximum amount of axle articulation, the springs would be put to work extra hard in order to cope up with the terrain
Leaf springs, by design, fail due to fatigue. Fatigue means a low to moderate load (that is way below the spring load capacity) applied continuously over a long period of time. This is different from a single sharp high load impact on the spring.

The Control Arm/Torque Rod Bushings tend to wear out quickly as they are made of Rubber
Once these are worn out, there will be noticeable change in the handling behaviour and also tyre wear
The rear suspension will feel loose and unstable in high speed
Aftermarket Polyurethane material Bushings tend to give better performance in terms of durability and long-term elasticity retention.

Uneven Tyre wear on the wheels
The reason this happens is due to the tires missing their alignment
The best way to deal with it is to get the alignment done at a place that does alignment for Trucks. Car and Van alignment shops might not be able to do a good job.
If an alignment did not solve the issue, then it might be the case that the suspension bushings have failed.
The factors influencing this excessive tyre wear would be the
- Axle Load Pad insulators (top, bottom and lateral)
- Trunnion Bushing
- Leaf Spring Pack U-Bolt Preload
Also check the center distance between the axles on both sides. Use the in-built adjustment to align the axles back to the manufacturer recommendations.

Conclusion

In this brief article we have discussed the different Mack Camelback Suspension problems, what the causes are, and Troubleshooting Tips.