Steering Rack Coupling Bushes

Nolathane steering rack coupling bushes rebuild the flexible joint between your steering column and your steering rack or steering box. Often called a rag joint or flexible coupling, this small part carries every turn of the steering wheel. When its bush wears, the steering develops play, feels vague around centre and loses the direct, connected feel that makes a car enjoyable to drive. A Nolathane polyurethane coupling bush restores that connection.

Each kit includes the coupling bush and the hardware needed to rebuild the joint on applicable vehicles. They?re ideal for classic Australian, European and Japanese passenger vehicles, as well as other models that use a flexible disc steering coupling.

What the Steering Coupling Does

The steering column and the input shaft of the steering rack or steering box rarely sit in a perfectly straight line. The steering coupling joins the two shafts and allows for small misalignments between them, while transmitting steering input from the wheel to the steering mechanism.

On many vehicles, the coupling is a flexible disc bolted between two flanges, one on the column shaft and one on the rack or box input shaft. Bolts pass through alternating holes in the disc, connecting each flange to the bush. The disc twists slightly to accommodate misalignment, and it absorbs some vibration and road shock before they reach the steering wheel.

Because every steering input passes through it, the coupling must be firm and free of play. Even a small amount of movement here is felt directly at the wheel.

Rag Joints, Universal Joints and Flexible Couplings

Steering shafts are joined in different ways depending on the vehicle:

• Flexible disc couplings, or rag joints, use a bush between two flanges. They?re common on classic and older vehicles and on some steering box applications.
• Universal joints use a metal cross-and-yoke design to allow larger angles between shafts. They?re common on multi-piece steering shafts.
• Combination designs use universal joints along the shaft, with a flexible coupling at one end.

Nolathane steering rack coupling bushes are designed for flexible disc couplings. Check that your vehicle uses this type of coupling before ordering.

Signs of a Worn Steering Coupling Bush

• Free play at the steering wheel before the wheels begin to turn
• A clunk or knock felt through the wheel when changing direction
• Vague, wandering steering, especially around the straight-ahead position
• Steering that feels different turning left and right
• Increased vibration through the steering wheel
• Visible cracks, splits, swelling or oil contamination on the coupling disc

Because the steering coupling is safety-critical, have any of these symptoms inspected without delay.

Why Steering Coupling Bushes Wear

Steering couplings sit in the engine bay, often close to the exhaust manifold and other hot components. Over time, factory rubber discs are affected by:

• Heat, which hardens and cracks the rubber
• Oil, power steering fluid and grease leaks, which soften and swell the rubber
• Constant twisting from steering loads, which fatigues the material
• Age, especially on classic vehicles with original couplings

As the disc deteriorates, the bolt holes elongate and the material stretches, allowing the two flanges to move relative to each other. That movement is felt as play at the steering wheel.

Polyurethane vs Rubber Steering Coupling Bushes

Factory steering coupling discs are usually reinforced rubber. Nolathane steering coupling bushes use a superior polyurethane formulation with outstanding elasticity, memory and durability. They resist oil, grease, ozone and weathering far better than rubber, and they hold their shape under steering loads.

The result is positive steering precision and feedback, with cleaner, more direct transfer of input from the wheel to the rack or box, and a much longer service life in the harsh conditions of the engine bay.

Sharper Steering for Classic and Performance Vehicles

For classic cars, sharp steering is a big part of the driving experience. A fresh polyurethane coupling bush, together with new rack bushes, idler arm bushes and other steering components, brings back the crisp, connected steering the vehicle had when new.

For performance-focused classics, club cars and track day vehicles, a firmer coupling bush reduces the elasticity between the steering wheel and the rack. That helps the car respond more precisely to small inputs and gives the driver clearer feedback from the front tyres.

Repairing the Coupling Instead of Replacing It

When a steering coupling wears, the flanges and shafts are often still in good condition, and only the flexible disc has failed. Rebuilding the coupling with a new bush restores steering precision without the cost of a complete coupling, steering shaft or column. On classic vehicles, where complete couplings can be difficult or impossible to find, rebuilding is often the only practical repair.

Choosing the Right Coupling Bush

Steering coupling bushes are specified by several key dimensions:

• Outside diameter (OD): the overall diameter of the coupling disc
• Pitch circle diameter (PCD): the diameter of the circle through the centres of the bolt holes
• Thickness: the thickness of the disc between the flanges
• Bolt diameter: the size of the bolts that pass through the disc

Each listing shows the applicable vehicles and these dimensions, along with the kit contents, so you can confirm the right coupling bush for your vehicle.

Rebuilding a Steering Coupling

Steering coupling work is safety-critical and is best carried out by a professional workshop or an experienced mechanic. As a general guide:

• Set the front wheels straight ahead and centre the steering wheel.
• Mark the position of the column shaft, coupling flanges and rack or box input shaft, so everything is reassembled in the same orientation.
• Remove the coupling and dismantle it, noting the orientation of each flange.
• Fit the new Nolathane coupling bush using the tubes, bolts, washers and nuts supplied, alternating the bolts between the flanges as originally fitted.
• Tighten all fasteners to the specified torque, and secure them using the locking method supplied or specified.
• Reinstall the coupling in its marked position, and check that the steering turns smoothly from lock to lock without binding.

Have the steering and wheel alignment checked after fitting, to confirm the steering wheel is centred.

Lifetime Warranty

Nolathane steering rack coupling bushes are backed by a lifetime warranty against manufacturing defects in material and workmanship, for the original vehicle they?re fitted to. It reflects our confidence in the materials, design and manufacturing standards behind every Nolathane bushing.

Who Nolathane Steering Coupling Bushes Suit

Nolathane steering coupling bushes suit owners of classic and older vehicles with worn or perished rag joints, and drivers experiencing steering play, knocks or a vague, disconnected feel. They?re also used by restorers rebuilding original steering systems where complete couplings are hard to find, by enthusiasts wanting sharper, more direct steering in classic and performance vehicles, and by workshops carrying out steering repairs and restorations.

Shop Steering Rack Coupling Bushes

Replace worn couplings from Nolathane's steering parts range, or choose universal steering coupling bushes for older or modified vehicles.

Find the steering coupling bush kit for your vehicle, then order online with fast shipping or have it fitted by a Nolathane reseller. Our fitment guarantee means you get the right kit first time, and our local support team can help you confirm your coupling type and dimensions.