There is much to be said for fancy independent trailing arm suspensions, but the venerable leaf springs still have their place under many camper trailers, and justifiably so. There are good arguments for their use, the most obvious being that they are relatively easy to repair while in the outback.
You can always find a replacement main leaf spring somewhere that will allow you to limp into civilisation, and any broken smaller springs can be simply tied in place with wire as an emergency repair to get you to a replacement.
MOUNT ’N’ SPRING
What’s most significant with leaf springs though is how they’re mounted. The basic arrangement has always been a pin or bolt through a bush made of rubber – or, increasingly in recent years, polyurethane – to absorb the shock and allow some degree of flexibility at each end.
In recent decades, the trend has been towards installing greasable shackle pins so that there is the optimum level of flexibility in the mounts. For most camper trailer users, the type of fitment has not been a matter of choice; it was simply how the trailer came equipped when purchased.
There is a conundrum here. If you depend solely on dry bushes – whether polyurethane or rubber – you may suffer limited suspension movement due to friction around the shackle pins. And, if you have greasable shackles, the grease can hold dust and grit, which can lead to enhanced wear of the surfaces.
Polyurethane bushes are supposedly self-lubricating and are marketed as being the answer to all bushing requirements in suspensions. However, it should be noted that all vehicle manufacturers continue to employ rubber bushes, simply because they are more durable and last longer.
If your camper has non-greasable shackles, then you should be prepared to check the bushes annually at least, or after any major trip offroad, to ensure they are not being chewed out. At any level of wear, dust and grit will get in around the shackle pins and rapidly wear them away. At least with greasable shackles you have the option to effectively “flush” the joint out with grease.
THE GOOD OIL
If your camper came equipped with greasable shackles, then you must — repeat, must — have a grease gun, or have a good mate who has one that you can borrow freely.
Greasable shackles should be greased on a regular basis. If you only do relatively short trips up and down the highway then maybe once every six months is okay, but any time you do a major trip — over a couple of thousand kilometres or certainly any reasonable distance over dirt, especially if it involves water crossings — then they should be greased before and after the trip. If it’s a really long trip involving a lot of offroad work, take your grease gun with you and use it every now and then.
Any sign of squeaking from the shackles indicates that they need grease immediately. Use a quality grease — Lovells, for example, recommends a No.2 lithium complex base — and pump it in through the grease nipples until you have clean grease coming out around all the joints. Clean off the excess and you should be okay.
While greasable shackles are said to be superior, if you are not lubricating them often enough the grease will harden to the point of being almost a cement, preventing the application of fresh grease via the nipple and leaving you with dry, worn pins.
If this happens, your only choice is to replace them. New greasable pins aren’t expensive — under $20 each — and the work isn’t difficult. You should only need to replace the shackle pin; you can use the nipple from the original pin. Greasing access shouldn’t be a problem on a trailer but, if it is, you can purchase angled nipples to assist.
After thoroughly chocking the trailer and preferably attaching the hitch to your vehicle’s towbar (to guarantee no unwanted movement and take unnecessary loads off the jockey wheel), jack the camper on one side to the point where there is no load on the shackle pins. Place jack stands to support the camper so that the weight is not dependent on the jack.
Remove the nyloc nuts on the inside end of the pins and replace with old nuts partially screwed on, then tap the pins out with a hammer. Don’t even bother trying to clean the pins, simply throw them away and replace with new pins. Thoroughly grease all surfaces before installing the pins. Clean any grease off the threaded inner ends and install the nyloc nuts, doing them up firmly, but not all the way. Thoroughly grease the pins with your grease gun, then lower the camper to the ground before finally doing up the nyloc lock nuts all the way while the weight of the camper sits on the pins.
Check out the full feature in issue #84 January 2015 of Camper Trailer Australia magazine.