Is Your Leaf Spring Suspension On It’s Way Out?
There are few situations more unsettling than watching a three-tonne van performing acrobatics behind a tow vehicle at 100kph. Poor weight distribution is often blamed, but make the problem worse with loose suspension and you …
There are few situations more unsettling than watching a three-tonne van performing acrobatics behind a tow vehicle at 100kph. Poor weight distribution is often blamed, but make the problem worse with loose suspension and you have a recipe for disaster.
Identifying poor suspension is a handy attribute, and informing your service agent of the problem will make for smoother sailing down the road.
The most common suspension arrangement is still the traditional leaf pack suspension, especially in multiple axle configurations. The design is simple, long lasting and easy to service. But the inspection of a dual axle system under this well-maintained and low-kilometre caravan delivered some surprising results.
WHAT TO LOOK FOR
Identifying issues with suspension wear is really quite simple, but does involve lowering yourself down to its level. Take some basic tools such as a good torch, a lever, a straight edge, and some spanners. This isn’t a service, just a really good look for tell-tale signs.
Misalignment of pins where the eye of the leaf pack is held is easy enough to see. Where the eye is not centrally located to the pin it usually suggests worn bushes. Jacking the van up slightly may also show the leaf eye moving easily around the pin, confirming the issue. Using a lever to move the leaf or rocker will also show loose parts moving easily.
The leaf pack should be all lined up nicely if everything is working as it should. Loose or stretched U bolts or spring clips can allow the leaf blades to move sideways. Fish plates, the part your U bolts secure through, that are worn or over-sized for the U bolt and leaf pack sizes can also contribute to this issue.
Use a straight edge to see if the rocker arm pins align. This example shows the van bracket sitting lower in the rocker arm due to worn bushes, creating a lot of uncontrolled travel in the suspension.
THE NEXT STEP
Once issues are identified, the next consideration should be, “Can I do this, or does it require an experienced hand?” There is much to be said for engaging an experienced mechanic who is familiar with repairing suspension. There are tricks of the trade in every field but they’re not really tricks, they are lessons learned – skills gained – experienced applied. Tapping into this is pool of knowledge can save a lot of money and ravaged knuckles.
But whichever option you choose, taking apart the components and making a ‘bin or save’ decision should not be done with expense in mind, but safety. This is not a task you want to be doing regularly, and neither do you want to be gripping the steering wheel on your next adventure, anxiously waiting for that first tail flicker because you saved fifty bucks using the old rockers. So take a few moments to get familiar with the underside of your van and you may well be glad you did.