This information is intended as a guide only
Suspense Stories: Basics of Maintaining and Upgrading 4x4 Suspensions
Without suspension, driving your car would be a dangerous, rickety, noisy and somewhat unpleasant experience. It keeps the wheels on the ground, makes steering possible and allows you to carry stuff around.
The job done by the suspension of a typical 4x4 vehicle is far more important. There could even be an argument for it being the most important component. Well, of course the drivetrain is pretty important too, but with the Land Rovers I've owned, I've found that it's mainly the suspension that makes it one of the best off-roaders out there.
It is important that the suspension is looked after effectively, especially if you do a lot of green-laning or off-roading, to ensure safety and economical usage.
Suspension problems can affect any car and identifying them before they start causing problems can save a whole lot of hassle. So it’s worth knowing what issues to look out for and how to go about fixing them. There can be an endless stream of issues that come about with the suspension and here are a couple of examples:
A shock discovery!
There's more than one thing that can go wrong with the shocks but a bent shaft and leaky shocks are most common. Leaky shocks occasionally go unnoticed, that's why it's important to inspect them for visible or tangible oil leaks. If the drive is becoming stiff and bumpy, query a bent shock shaft. Bumpy ride may also suggest a sheared shock mount. Whenever there's something wrong with the shocks, it requires immediate attention. And there is a reason why shocks always come in pairs. Even if only one shock is broken, you have to also replace the healthy one. Otherwise it may become a safety and handling issue.
Regardless of what type of springs your vehicle has got installed– coil or leaf (or torsion bar if you happen to be driving a French car) – there comes a time when the springs become too tired to do their job properly. When a spring loses its bounce, it goes saggy and impacts handling of a vehicle. A good tell-tale sign is an uneven wear of the tyre thread but sooner or later you also notice a considerable change in how the vehicle handles. There's only one cure – replace the springs.
Addressing issues with faulty suspension in a timely manner means you'll be saving money on tyres, petrol and future repair of other components that the bad suspension might have impacted.
Upgrading your suspension
There are two types of 4x4 upgrades. Most drivers will simply want to fix some development issues that the engineers didn't bother to fix while designing the car, or make minor improvements to reduce the body roll.
For example, the Range Rover P38A – one of my all-time favorite classic Land Rovers – came with a state-of-the-art air suspension where electronically controlled air springs completely replaced the old-school coil springs. The next generation – Range Rover Sport continued the trend, only its air suspension is even more sophisticated. It’s a well-conceived car, and even the recent popularity studies place the Range Rover Sport amongst the best used cars.
While the air springs don't leak air and the electronics are working properly, it's a joy to ride. It's got various setups, including a high-one for wading through deep water. However, when the air spring goes awry, you wish you'd bought something not as sophisticated!
Land Rover recommend to change the air springs once every 5 years. Next time the change is due, why not consider going back in time and get a nice set of coil springs. To tell a good spring conversion kit from a bad one, there are two important things to look for. Firstly, are the springs variable-rate? A good spring looks like it consists of two sections where the spacing between coils is noticeably different. Putting plain springs on your P38A will make the ride unpleasant. Secondly, does the kit come complete with an EAS override switch? If not, your Land Rover's electronics will go bonkers and you'll run into more problems than you began with.
The most frequent fault on P38A suspension is air leak. Although you can buy special fluid to detect air leaks, it’s much cheaper and equally effective to test the leaks using soapy water. Just look for bubbles appearing.
Another frequent fault is compressor failure. In most cases it isn’t as bad as it sounds because the real culprits often sit in the fuse box. If you unplug relay 20 and connect its output jack to the battery, the pump should run. If that’s the case, you may get away with replacing the Fuse 44 or the Maxi Fuse 2. The Relay 20 can be to blame too.
Something that is much more expensive to put right is a failure of the valve block. A tell-tale sign is slow rise after leaving the car overnight. If it struggles to pump it up, the air might be leaking from the line (if you’re lucky) or inside the valves, which means a write-off.
Despite the potential problems, many off-road enthusiasts like the air suspensions. Although they have to be more careful as to not to puncture the air bags with branches and other sharp objects hiding in the mud.
Ready for some serious off-roading?
Like with everything in life, when attempting to modify your vehicle, you begin with the basics. Start on the ground and build your way up. Yes, I mean the tyres. The choice of tyres will eventually determine ALL the other component choices and the cost of your conversion.
Picking huge tyres with perfect off-road capabilities might be very tempting but if you're doing green-laning twice a year to entertain your friends, going for the biggest possible tyres wouldn't be a good decision because you'll soon become your petrol station's best customer.
Also, big tyres will mean that you have to rebuild the wheel arches. It's easy if you're rebuilding a Jeep Wrangler or a Land Rover Discovery I (in my opinion two of the best vehicles you could choose for rebuilding) because they are built on a ladder frame, which makes any body modification a very easy job. When it comes to monocoque-bodied 4x4s, think twice before widening the arches. This is a high-intrusion, high-impact job that requires either a lot of skill or a lot of money.
If you're using the car both for everyday driving and an occasional off-road outing, you'd be wise to settle for a compromise. Not one of my favorite words, but the so-called on-road/terrain tyres are usually good enough for the majority of the 4x4 owners. The professional off-road tyres take you to a totally different territory. The usual marketing spin of comfort and improved mileage doesn't work in this territory any more. New rules, new goals – these tyres are designed for grip and performance. Yes, they're still street-legal, but don't expect them to perform as well on a hard surface.
Now that we've chosen the wheels, it's time to look at suspension. No serious 4x4 modification can be accomplished without getting rid of the factory suspension. The mainstream conversion kits should allow you to achieve a 2-3 inch lift, which should be enough, unless you're building a big-foot.
Before attempting to modify any suspension, it’s important to consider whether the chassis or the axles need additional supporting to avoid causing the car to disintegrate. Check this for some inspiration.
It doesn't go uphill now!
Larger tyres will inevitably rejig the gear ratios. In fact, they will raise the gears – the complete opposite of what you need for successful off-roading. That's why changing differential ratios or the transfer box ratios would be a good thing to do. Depending on the model of your Land Rover, this also could be the most difficult/expensive step of the whole project.
As far as the final touches are concerned, you may want to install a winch and safeguard the vehicle's floor with custom-made steel plates (because you'll be wading through muddy water and who knows when you hit that next big stone). These final alterations are going to add extra weight and the lift you've achieved in the previous steps, might give a bit. So make sure you get rid of all the unnecessary creature comfort bits like the AC, soundproofing and back seats.
Check the main suspension page to see what Land Rovers are really capable of.