Coromal Suspension Issues Explained

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

What are the most common  Coromal suspension issues? 

The most common  Coromal suspension issues are:

  • Wishbone Bush Failure
  • Leaf Spring Breakage
  • Leaf Spring Pad wear out
  • Tyre Scrubbing

Coromal Suspension Set-up

The  Coromal Suspension is of mainly two types:

  • Tourer
  • Sport
  • Dexter 2.7T Torsion Axle

Tourer: Wishbone with leaf spring

The set-up is an independent suspension. In the case of a twin-axle trailer, the 4 corners are controlled by large wishbones, each of which are nearly half the width of the trailer. Because of the wishbone shape this suspension setup is also called a “Knee Axle”. The end of the wishbone is attached to a leaf spring that is supported at the chassis with slider wear-pad supports

Sport: Wishbone with Double Coil Springs

Here again, the set-up is an independent suspension. In the case of a twin-axle trailer, the 4 corners are controlled by large wishbones, each of which are nearly half the width of the trailer.

The end of the wishbone is attached to 2 coil springs that are supported at the chassis with spring seats.

Dexter 2.7T Torsion Axle

The Torsion axle is available for small sized variants of the Adventure seeker series.

Wishbone Bushing Failure

  • The wishbones are attached to the chassis through Bushing connections
  • These bushings, wear and weather over time, ultimately disintegrating
  • Once the bushings fail, the wheel alignment tends to be out very often
  • This leads to uneven tire wear issues
  • In most branded axle products, the spares would be available for a replacement

Leaf Spring Breakage

  • Steel suspension Leaf Springs are always prone to breakage
  • In a suspension that is Off-road oriented, it is expected to see several leaf spring breakages
  • Leaf springs used in Coromal are generally the Semi-elliptic type
  • The Semi-elliptic type of leaf springs undergo interleaf frictional wear and fatigue over long-term usage. This wearout is accelerated in an Off-road situation.

Leaf Spring Pad wear out

  • The spring wear pads, are continuously under high pressure, since the contact is concentrated at a small patch
  • The high pressure contact leads to high wear 
  • This tends to be one of the highest wear items, apart from the leaf springs themselves

Tire Scrubbing

  • Uneven Tyre wear on the wheels
  • The reason this happens is due to wishbone bush failure
  • 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 axles are bent. 
  • In order to check axle bened, you can use a straight edge plank or a sheet-metal channel of roughly 1-2 mtr and place it over the edges of both the tyres on the sidewall.
  • Ideally, there must be no gap between the tires and the plank. If there is a gap, then it means that there is an issue with either of the axles
  • 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.

Tire Hitting the Caravan Body

  • This usually happens in the Wishbone+Leaf Spring type of suspension
  • Mostly seen occurring in the Coromal Silhouette
  • The axle becomes unstable over rough roads
  • Occasional hitting of the Tires against the Caravan Body
  • The first Probable cause could be the fitment of an aftermarket wheel that was slightly bigger than the recommended Tire size
  • The next probable cause could be the breakage of the leaf spring sliding supports. This is the part that maintains the distance between the axle and the body. Once this bracket breaks, the axle moves closer to the caravan body, causing possible hitting of the Tires.

Conclusion

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

Frequently Asked Questions

What are the different types of Caravan Suspension in Off-Road application?

  • Leaf-Spring Suspension
  • Airbag Suspension
  • Independent trailing arm Suspension
  • Independent Torsion Axle Suspension
  • Independent tandem axle suspension

Leaf Spring Suspension

Leaf Springs are the most popular among suspension systems. They are primitive in concept, yet are reliable and easy to maintain. They provide a decent amount of articulation and can handle off-road conditions. The only drawback is that the ride quality in a leaf spring suspension would not be as good as a coil spring or torsion beam or air bag suspension.

Air Bag Suspension

Air Bag suspension provides the best ride quality among all types of suspension. The reason being that air bellows have a different resonant frequency and can operate at a different natural frequency that does not resonate with the frequencies of road inputs. The leaf springs have interleaf damping and therefore limit the range of damping control possible using shock absorbers. In the air suspension, since air bags have no internal damping, it makes it easier to control damping using a shock absorber. The drawback with Air Bag Suspension is that air bags are prone to wear, cracking and air leaks in the long-term. Air bag replacements are generally more expensive compared to other suspension types. The air suspension system is a bit complex due to the number of parts involved. The air suspension operates only under air pressure. A leakage therefore means that the whole suspension becomes non-functional.

Independent trailing arm Suspension

An independent trailing arm wishbone suspension would be a really good choice for caravans going off-road. This is a configuration that would work better compared to a leaf spring setup. The Trailing arm ensures the most suitable wheel alignment and suspension behavior suited to a trailing axle.

The ride comfort can be tuned using appropriate shock absorber settings.

Independent Torsion Axle Suspension

The Torsion Axle suspension works on Rubber Chords that twist inside the swing arm stub axles. The torsion axle is suited more for light-duty caravans and provides a good amount of flexibility. The Torsion axle may not be the best choice for heavy-duty applications. The torsion axle does have one drawback though. It does not come with shock absorbers as a standard. This could make the ride bumpy in some situations, like uneven roads.

Independent tandem axle suspension

There are many options available for independent tandem axles that are meant for longer trailers. There are also choices in spring setup like leaf springs and coil wishbones. The leaf spring tandem arrangement would involve a combination of trailing arms and leaf springs. The coil spring tandem suspension would involve trailing arms and coil springs.

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