Leaf Spring Shackles

Nolathane leaf spring shackles connect the rear eye of a leaf spring to the chassis, giving the spring room to flex. They?re a small part with a big job: every time the suspension compresses, the spring gets longer, and the shackle swings to let it. Worn, bent or seized shackles stop the spring moving freely, which shows up as a harsh ride, squeaks, clunks and a rear end that won?t stay settled.

Replacing leaf spring shackles restores smooth spring movement and firm axle location on 4WDs, utes, vans and other leaf sprung vehicles. Greasable designs go further, letting the shackle bushes be lubricated in place for a longer, quieter service life.

How a Leaf Spring Shackle Works

A leaf spring is curved when it?s unloaded. As weight is added or the wheel hits a bump, the spring flattens, and as it flattens it gets longer. If both ends of the spring were bolted rigidly to the chassis, it couldn?t lengthen, and the suspension would bind.

The shackle solves this. It?s a short link, usually made of two side plates joined by pins, that hangs between the chassis and the rear spring eye. As the spring lengthens and shortens, the shackle swings back and forth on its pins, letting the spring flex freely while still holding it to the chassis.

Shackle Angle and Why It Matters

The angle of the shackle has a big effect on how the suspension behaves. At normal ride height, a correctly designed shackle sits at a slight angle, so it can swing in either direction without reaching the end of its travel.

If the shackle angle is wrong, problems follow:

• A shackle that hangs almost vertical can make the rear feel unstable and allow sideways movement
• A shackle that sits nearly flat can bind, making the ride harsh and limiting suspension travel
• In extreme cases, a shackle can flip past centre, called shackle inversion, which jams the suspension

Shackle angle changes when ride height changes, which is why raised or lowered vehicles need their shackles checked.

Signs of Worn Leaf Spring Shackles

• Squeaking or creaking from the rear of the springs over bumps
• Clunking when taking off, braking or going over speed humps
• A harsher ride than usual, especially over small bumps
• The rear of the vehicle wandering or feeling unsettled under load
• Rust, cracking or bending on the shackle plates
• Seized pins or bushes that won?t let the shackle swing
• Elongated holes in the shackle plates
• Cracked or extruded bushes at the shackle or rear spring eye

Greasable Leaf Spring Shackles

Factory shackles usually have plain pins that can?t be greased. Water, dust and grit work into the bushes, wear them out and eventually seize the pins. Greasable shackles add grease fittings and passages, so fresh grease can be pumped through the pins to push out contaminants and keep the bushes pivoting smoothly.

Greasable shackles are especially worthwhile on vehicles that tow, carry heavy loads, drive on beaches or cross water regularly. Pairing them with polyurethane bushes gives the longest life. Nolathane has been making polyurethane suspension bushings since 1974, originally developed to replace brass bushes in hillclimb competition. The signature red bushings are made in a range of durometers (hardness grades) for each position, and offer outstanding abrasion resistance, high load-bearing capability and resistance to oil, grease, ozone and weathering.

Extended Leaf Spring Shackles

Extended, or longer, leaf spring shackles are sometimes used to raise the rear of a vehicle. They can add a small amount of height, but they also change the shackle angle and can reduce stability by allowing more sideways movement. On a lifted vehicle with taller springs, a shackle of a different length may be needed to bring the angle back into the correct range.

Any change to shackle length should be made with care. It affects ride height, handling and compliance, and in many jurisdictions it counts towards the total lift. Rules vary between Australian states and in the UK and Europe, including MOT or periodic inspections, so check the requirements where your vehicle is registered and tell your insurer about any modifications.

Replacing Shackles in Pairs

Leaf spring shackles should always be replaced in pairs. A new shackle on one side and a worn one on the other leaves the axle located unevenly and can make the vehicle sit or behave differently side to side. For the best result, renew the fixed pins, front eye bushes, rear eye bushes and shackle bushes at the same time, and fit new U-bolts if the springs are removed from the axle.

Fitting Leaf Spring Shackles

Fitting suits professional workshops and experienced home mechanics. As a general guide:

1. Park on level ground, chock the front wheels and support the chassis securely on stands.
2. Support the axle with a jack to unload the springs.
3. Work on one side at a time, removing the shackle pins and the old shackle.
4. Remove the old shackle and rear eye bushes and clean the mounting points.
5. Fit new bushes with a grease suitable for polyurethane.
6. Fit the new shackle in the correct orientation, with any grease fittings positioned for easy access.
7. Lower the vehicle onto its wheels and tighten the shackle pins to specification at ride height.
8. Grease the fittings until fresh grease appears, then repeat on the other side.

Check that the shackle sits at the correct angle once the vehicle is on its wheels, and re-check torque after the first few hundred kilometres.

Maintaining Greasable Shackles

Grease greasable shackles at every service, after beach driving, water crossings or mud, and after long trips on dusty or corrugated roads. Clean each fitting before greasing so dirt isn?t pushed into the joint, and pump until fresh grease appears. Inspect the shackle plates for rust or cracks at the same time.

Choosing the Right Shackles

Shackles differ in length, width, pin size and design between vehicles. Confirm the vehicle, drivetrain, body style and model year, and check whether the vehicle has standard or raised suspension before ordering. Each listing shows the vehicles the shackles suit, and our fitment guarantee means the shackles you order for your vehicle are confirmed to suit it.

Shop Leaf Spring Shackles

Shackles belong to Nolathane's leaf springs range, and new leaf spring bushes are worth fitting at the same time.

Find the leaf spring shackles for your vehicle, then order online with fast shipping or have them fitted by a Nolathane reseller. Every product is backed by Nolathane?s warranty, 60-day returns give you time if a part isn?t right, and our local support team can help whether you?re curing a squeaky rear end, servicing a working ute or preparing a 4WD for touring.