Leaf Springs with Fitting Position Front Axle, Rear Axle for JEEP CHEROKEE XJ

A leaf spring carries the load and locates the axle at the same time, which is why it is still the rear end of choice on your XJ CHEROKEE on anything built to work.

Formula 4x4 leaf springs are built around Australian load bands and Australian surfaces, from 50kg through to 800kg and 20mm to 80mm of lift.

What Are XJ CHEROKEE Leaf Springs and How Do Leaf Springs Work

A leaf spring is a stack of curved steel plates clamped together at their centre, bolted to the chassis at the front and to a swinging shackle at the rear.

Load the vehicle and the arc flattens, which stores energy and absorbs the input. As the arc flattens the pack also gets longer, which is what the rear shackle is there to allow.

The leaves slide against each other as that happens, and the friction between them damps the movement. That self damping is why leaf sprung vehicles were usable before shock absorbers existed, and it is also why a leaf pack feels firmer over small bumps than a coil does.

The part that separates a leaf spring from a coil is the second job. A coil only springs, so the axle needs trailing arms, radius arms and a panhard rod to hold it in place. A leaf spring springs the vehicle and locates the axle on its own, which is fewer components doing more work.

That is why leaf springs persist on bakkies, trays and anything carrying weight. They spread the load along a length of chassis rather than concentrating it at one mounting point.

How Should XJ CHEROKEE Leaf Springs Look

The single most useful check costs nothing and takes a minute.

A healthy leaf spring arcs upwards, with clear curvature through the pack when the vehicle is at normal ride height and unloaded. The main leaf should be the most curved, with the shorter leaves following that arc beneath it.

A flattened pack has lost most of its travel even if nothing has broken. Flat is the warning sign, and a pack that has gone past flat and arcs downward is well beyond its service life.

Compare left to right while you are there. Both sides have carried the same vehicle over the same roads, so a visible difference between them points at one spring having given up.

Check the pack is sitting square on the axle, with the leaves aligned at the centre rather than offset from each other.

What Do Bad XJ CHEROKEE Leaf Springs Look Like

• A flattened pack with no upward arc remaining
• One side sitting visibly lower than the other
• The rear of the vehicle sitting low with nothing in the tray
• Leaves spread apart or offset at the centre
• A cracked or broken leaf, usually visible as a gap or a dropped end
• Heavy corrosion or flaking rust between the leaves
• Bottoming out on the bump stops over bumps the vehicle used to absorb
• Squeaking or groaning from the rear at low speed
• Axle tramp or hopping under hard acceleration
• Worn shackles, bushes or hangers with visible play

How to Tell If Your XJ CHEROKEE Leaf Springs Are Bad Without Removing Them

Measure rather than guess, because sagging develops slowly enough that drivers adapt to it.

Park on genuinely level ground with the tyres at correct pressure, since an underinflated tyre reads as a sagged spring.

Measure from the centre of the wheel hub vertically to the lip of the guard above it, at both rear corners. Compare the two sides first, then compare against where the vehicle used to sit.

Load your XJ CHEROKEE the way you normally run it and measure again. A pack that holds its height empty and collapses under load is rated below what you are carrying, which is a specification problem rather than a worn out spring.

Photographs of the vehicle from a year or two earlier are often more revealing than memory.

Formula 4x4 XJ CHEROKEE Leaf Spring Load Ratings

The rating is the number that decides whether a leaf spring does its job, and it matters more than the lift height.

Formula 4x4 leaf springs cover constant loads from 50kg through to 800kg, with lift heights from 20mm to 80mm across the range.

Constant load means the weight permanently on the vehicle rather than the weight of the vehicle itself. A canopy, drawers, a water tank, a fridge, a second battery and recovery gear reach the middle bands faster than most owners expect.

Choose a rating below what you carry and the pack flattens under load and sits lower than standard. Choose far above it and the vehicle rides harshly and sits tail high with an empty tray.

Front and rear are rated separately on vehicles with leaf springs at both ends, since the front carries accessory weight while the rear carries payload.

Weigh the vehicle fitted out if you can. The number is almost always higher than the estimate.

Spring Steel and Construction

What a leaf spring is made from decides whether it holds its rate over years of cycling.

Formula 4x4 leaf springs are made from high grade carbon spring steel in the SUP9 and SUP9A grades, which is the material class suited to sustained cyclic loading rather than a lower grade made to hit a rate when new.

Lower grade steel can be made to produce the right rate on day one and will fatigue sooner. What follows is a vehicle that has quietly sagged with nothing visibly broken, which is the most common end of life for a leaf pack.

Heat treatment is the other half of it. Hardening and tempering decide the finished toughness, and a pack that has been treated inconsistently has one leaf carrying more than its share.

Tapered Ends and Inter-Leaf Graphite Coating

Two features deal with the friction that makes a leaf pack harsh and noisy.

Tapered leaf ends thin the end of each leaf so the transition between leaves is gradual rather than a step. That spreads the contact load and reduces the stiction that makes a pack resist small movements before it begins to flex.

Inter-leaf graphite coating reduces friction between the leaf surfaces directly. Less friction means a smoother initial response, less noise, and less of the wear that eventually eats into the leaf surfaces.

Both address the main complaint about leaf sprung vehicles, which is that they feel firm and noisy over small inputs while working perfectly well under load.

How to Stop XJ CHEROKEE Leaf Springs From Squeaking

The squeak is dry metal on dry metal, and it tells you the friction surfaces have lost their protection.

On a coated pack the graphite has worn away at the contact points. On an uncoated one there was never much there to start with.

A permanent fix means separating the leaves, cleaning the contact faces and treating them, which is workshop work rather than a spray can job. Spraying lubricant into the edges of an assembled pack quietens it briefly and washes out.

Check the bushes while chasing a squeak, since worn spring eye and shackle bushes make a very similar noise and are the more common cause on an older vehicle.

A pack with worn inter-leaf surfaces is also wearing itself, so a persistent squeak is worth acting on rather than living with.

XJ CHEROKEE Leaf Springs for Towing and Carrying Weight

Leaf springs suit load for a reason, and matching them to what you actually tow is the difference between a vehicle that sits level and one that does not.

Ball weight sits behind the rear axle and levers the front of the vehicle up, which takes weight off the steering and changes how the vehicle brakes before it changes anything else.

A spring rated for the ball weight plus whatever is in the tray keeps the vehicle level hitched, which is what keeps the headlights pointed at the road and the steering feeling normal.

Towing regularly on an underrated pack is also the fastest way to flatten it, since the spring spends its life working near the limit of its range.

Single Leaf Springs and Leaf Spring Kits for the XJ CHEROKEE

Springs are sold both ways and the right choice depends on what else is due.

A single leaf spring suits replacing one side after damage, or a vehicle where the U-bolts, bushes and shackles were renewed recently and only the pack has reached its end.

Where one side has failed, the other should still be assessed. Fitting a new spring against one that has done 150,000 kilometres leaves two different rates on the same axle, which shows up as a lean and uneven tyre wear.

A leaf spring kit supplies the springs with the hardware that should go on with them, which is the better value on any vehicle where the pack is coming off anyway. The U-bolts cannot be reused and the bushes will be due, so buying them separately rarely saves anything.

Front and rear are listed separately on vehicles with leaf springs at both ends, since the ratings and the dimensions differ.

Why Australian Conditions Are Harder on XJ CHEROKEE Leaf Springs

Corrugations are the test that sorts a spring pack out, and they are what Formula springs are specified around.

A corrugated road cycles the suspension continuously at high frequency, which works the leaves against each other thousands of times a kilometre. Fatigue accumulates with those cycles rather than with distance alone, so a remote touring trip uses more spring life than the odometer suggests.

Corrosion is the second factor and it runs on time rather than distance. Water and grit work between the leaves of a conventional pack and sit there, attacking the surfaces from the inside where nobody inspects. Coastal air, beach work and water crossings all accelerate it, and corrosion pitting is where most leaf fractures start.

Heat is the third, through the dampers rather than the springs. A spring that keeps working while the shock absorber beside it has faded leaves the vehicle unsettled, which is why springs and dampers are specified as a pair.

Weight is the constant underneath all of it. A loaded vehicle on corrugations is asking considerably more than the same vehicle empty on bitumen.

Formula 4x4 XJ CHEROKEE Leaf Spring Warranty

Formula 4x4 leaf springs carry a three year or 60,000 kilometre warranty, whichever comes first, subject to the applicable terms.

That cover reflects where these springs are expected to work, which is loaded vehicles on corrugations and unsealed roads rather than a smooth test loop.

How to Change XJ CHEROKEE Leaf Springs

Leaf spring work involves heavy components with the vehicle supported, and a pack under its own arc moves once the fasteners come off.

New U-bolts go on every time without exception. U-bolts are torqued into their yield range and stretch permanently, so a reused one feels tight while clamping far below what it did new. What follows is load transferring to the centre bolt, which was never sized to carry it.

Replace the spring eye and shackle bushes at the same time, since the access is already paid for and they wear on the same timeline.

Check the hangers and shackle plates for elongation and corrosion while everything is apart.

Torque the U-bolts evenly and in sequence, then retorque after the first few hundred kilometres once the pack has settled. That retorque after bedding in is not optional.

Have a wheel alignment done afterwards, since changing ride height moves the geometry immediately.

Find Formula 4x4 Leaf Springs for Your XJ CHEROKEE

Leaf springs are part of the Formula 4x4 suspension springs range, with parabolic leaf spring kits and single parabolic leaf springs for touring rigs that carry weight every day.

Select your XJ CHEROKEE to see the leaf springs available for it across the full range of load ratings and lift heights. Work out what your vehicle permanently carries before choosing a band, because the rating decides whether it sits right loaded rather than just empty.