NOLATHANE Trunnion Bushing

Nolathane trunnion bushings cushion the trunnion and pivot at the outer end of the lower control arm on classic trunnion-type front suspension. Each trunnion bushing lets the suspension pivot smoothly while holding the wheel?s upright firmly in place. When they wear, the front wheels develop play that shows up as shimmy, wander, and vague steering.

Trunnion bushings are a key part of any front suspension rebuild on a classic or vintage vehicle, where good replacement parts can be hard to find. Each listing shows the positions included and the vehicles each kit fits.

How a Trunnion Front Suspension Works

Before ball joints became common, many vehicles used a trunnion to connect the suspension to the wheel. In a typical layout, the outer end of the lower control arm, sometimes called the lower wishbone, carries a trunnion. The trunnion connects to the vertical link, or upright, that holds the wheel hub.

The trunnion lets the vertical link pivot up and down as the suspension moves over bumps. Steering is handled separately by the kingpin, sometimes called the swivel pin, which lets the wheel turn left and right. The trunnion handles suspension movement, while the kingpin handles steering rotation.

Exact layouts vary between vehicles, so check the design of your own front suspension before ordering. The trunnion bushings cushion the pivot points, allowing smooth movement while keeping the parts accurately located.

Trunnions and Ball Joints Compared

Modern vehicles usually use ball joints, which combine suspension and steering movement in a single sealed joint. Older designs used trunnions and kingpins, which separate those movements into different pivots.

Trunnions were robust and serviceable, but they need regular lubrication and they wear in a different way from ball joints. Instead of a single joint wearing out, play can develop at the trunnion bushings, the kingpin, or the trunnion threads.

That?s why trunnion wear is often overlooked when diagnosing front-end play on classic vehicles. Owners and mechanics used to ball joints may check the obvious parts and miss the trunnion entirely.

Trunnion and Pivot Bushing Positions

Trunnion-type front suspension uses bushings at a few key points. Each listing shows the positions included.

Trunnion Bushings

These fit at the trunnion itself, where the lower control arm connects to the vertical link. They cushion the pivot that carries the suspension?s up and down movement.

Lower Control Arm Pivot Bushings

At the inner end of the lower control arm, pivot bushings connect the arm to the chassis. These carry the arm?s movement as the suspension travels and are often replaced at the same time as the trunnion bushings.

Signs of Worn Trunnion Bushings

Worn trunnion bushings usually show up as looseness at the front wheels. Watch for:

• Play at the top and bottom of the front wheel
• Clunks over bumps
• Shimmy, especially at certain speeds
• Wander, where the vehicle needs constant small corrections to stay straight
• Vague or imprecise steering
• Uneven wear on the front tires
• Hardened, cracked, or missing bushing material when the suspension is taken apart

Inspecting a Trunnion Front Suspension

A simple inspection can show whether the trunnion bushings are worn and where the play is coming from:

• Lift the front of the vehicle and support it safely on stands
• Grip the front wheel at the 12 and 6 o?clock positions and rock it in and out
• While someone rocks the wheel, watch the trunnion, the kingpin, and the lower control arm pivot

Movement at the trunnion points to worn trunnion bushings. Movement at the kingpin points to worn kingpins or their bushes. Movement at the inner pivot points to the lower control arm bushings. Pinpointing the source means you replace the right parts during the rebuild.

Rubber, Nylon and Polyurethane Trunnion Bushings

Original trunnion bushings were often made from rubber or nylon. After decades of use, or even long periods in storage, those materials harden, crack, and lose their shape.

Polyurethane trunnion bushings hold their shape well and resist oil, grease, ozone, and weathering. That makes them a good choice for classic vehicles, which often spend long periods stored or are only driven occasionally, conditions where rubber tends to deteriorate.

The trade-off is that polyurethane is slightly firmer than the original rubber, so you may notice a little more road feel through the steering.

Choosing Trunnion Bushings

Choosing the right kit starts with confirming your suspension design. Each listing shows the positions and vehicles it suits.

Front Suspension Design

Make sure your vehicle uses a trunnion and pivot layout before ordering. Similar-looking classic vehicles can use different front suspension designs.

Kit Contents and Positions

Check which positions are included, whether trunnion bushings, lower control arm pivot bushings, or both.

Matching Parts for a Full Rebuild

A full front suspension rebuild usually also involves the kingpins, trunnions, and seals. These are checked separately, so inspect them while the suspension is apart and replace any that are worn.

Fitting Trunnion Bushings

Trunnion bushings are part of the steering and suspension, so qualified fitting is recommended. The general process looks like this:

• Assemble the trunnion with the lubrication the vehicle?s design calls for and the listing specifies
• Tighten to specification without binding the pivot
• Check that the suspension moves freely through its full travel and the steering turns freely from lock to lock
• Have a wheel alignment carried out

Check everything again after the first few miles.

Limitations and Trade-Offs

Trunnion bushings are an important part of a rebuild, but they have limits:

• New bushings can?t fix a worn trunnion thread, worn kingpins or kingpin bushes, a bent vertical link, or a worn lower control arm
• Lubrication must be maintained for the trunnion to last
• Polyurethane transmits slightly more road feel than the original material
• Fitment is limited to the listed suspension designs

Compliance and Insurance

Make sure the vehicle meets the safety inspection requirements of the state where it?s registered, including any classic or antique registration rules. Let your insurance company know about modifications, since classic car insurers may have their own requirements.

Warranty and Support

Nolathane trunnion bushings carry a lifetime warranty against manufacturing defects in material and workmanship, for the original vehicle. Our local support team can help you confirm whether your vehicle uses a trunnion-type front suspension.

Shop Trunnion Bushings

Trunnion bushings are a classic car fix in our polyurethane bushings selection.

Find trunnion bushings for your classic vehicle and order online with fast shipping. Every kit is covered by our fitment guarantee.