Fixed Pins

The fixed pin is the one component in a leaf spring rebuild that almost everyone skips. New bushes go in, the old pin goes back through them, and the job is undone within a year.

These are greasable replacements for the pin at the fixed end of the spring, sold on their own and as part of complete kits with the bushings and shackles.

The Pin Is the Surface Your Bushing Runs On

This is the whole argument, and it is worth understanding before you order bushes without pins.

A polyurethane leaf spring bush does not twist the way rubber does. It slides on the pin running through it, which is what lets the spring pivot freely and stops the pack binding. That means the pin is not just a fastener holding things together. It is a bearing surface, and the condition of its outside diameter determines how the bush wears.

Original pins corrode. They sit in the worst position on the vehicle for water, salt and grit, and once the surface pits and scales it stops being smooth. Press a fresh bush onto a pitted pin and you have effectively fitted sandpaper inside it. The bush wears through in a fraction of the time it should, and the owner concludes the bushes were no good.

That is why the pins matter as much as the bushings do, and why replacing one without the other is a false economy.

Fixed Pin at the Front, Shackle at the Rear

A leaf spring is anchored differently at each end, and the two ends take different hardware.

The front eye is fixed. A pin passes through the spring eye bushing and the hanger, and that pin is what holds the axle's fore and aft location. It is the anchor point, so it carries the highest loading of the set and it does not move through an arc the way the other end does.

The rear eye is not fixed. It attaches to a shackle, which swings to let the pack change length as it flattens and extends under load. That end takes shackle pins.

Both use bushings, both need a smooth pin to run on, and both are worth doing together because they have covered the same kilometres in the same conditions. Complete kits pair the greasable fixed pin with the shackle and the bushings for exactly that reason.

Why a Grease Nipple in the Pin Matters

A standard pin has to be pulled out to relubricate the bush, which in practice means it never happens.

A greasable fixed pin carries a grease nipple, so the bush can be flushed from underneath the vehicle with a grease gun in a couple of minutes. That does two jobs at once. It maintains the film of grease the bush needs between itself and the pin, which is what the sliding design depends on. And it pushes the old grease out, taking whatever dust, mud and water it has collected with it.

On a ute or 4WD working on corrugations, dirt roads or through water crossings, contamination is what kills leaf spring bushes rather than load. Being able to flush the bore is the difference between a bush that lasts the life of the vehicle and one you replace every couple of years.

Keep pumping until fresh grease appears at the ends of the bush. Stopping when the gun meets resistance leaves the contamination sitting exactly where it was doing the damage.

What Worn Pins and Bushes Do to the Back End

The leaf spring does two jobs at once. It carries the load, and it locates the axle, holding it square under the vehicle.

The bushings at each end are the only compliance in that arrangement, so when they wear, the pack shifts fore and aft and rotates slightly under load. One side never moves by exactly the same amount as the other, so the rear axle is no longer square, the rear wheels point very slightly off straight, and how far off straight they point changes with throttle, load and cornering.

That is rear end passive steer. The vehicle wanders across the road, feels unstable under heavy braking, and it is at its worst exactly when you least want it, which is carrying a load or towing a boat or caravan. An alignment reads correctly because the shop measures the vehicle standing still.

Almost nobody suspects a corroded pin at the end of a leaf spring when the complaint is that the ute wanders with the camper on the back. That is why these go unaddressed for years.

Signs the Pins Need Replacing

• Visible corrosion, pitting or scale on the pin when the bush is removed
• New bushes that wore out far sooner than they should have
• A rear end that wanders under load or while towing
• Instability under heavy braking with a loaded tray or a trailer behind
• Squeaking or creaking from the rear over speed humps and driveways
• A grease nipple that will not take grease, which means the pin has seized in the bush
• A pin that will not drive out without a fight, which usually means it has corroded into the bush
• Any leaf spring job where the original pins have never been replaced

Doing the Job Once

Support the axle before anything comes apart, because a loaded leaf spring holds a serious amount of stored energy.

Expect resistance. A pin that has been in place for years has usually corroded into the bush and the hanger, and getting it out is often the hardest part of the job. Penetrating fluid and patience beat force, and a seized pin is worth cutting rather than damaging the hanger to save.

Replace pins, bushes and shackles together rather than mixing new and old. They have done the same kilometres, and putting a new bush on an old pin is the exact mistake this page exists to warn about.

While everything is apart, look at the centre bolt holding the leaves in alignment and the U-bolts clamping the pack to the axle. Neither is reusable once disturbed in the case of the U-bolts, since they develop their clamping force by stretching as they are torqued and will not generate the same clamp a second time.

Grease the bushes and pins on assembly with a lubricant made for polyurethane rather than whatever is on the bench.

Torque everything with the vehicle on its wheels at ride height rather than hanging at full droop. A bush clamped at droop sits preloaded in a position the suspension never returns to, so it binds and wears from the first kilometre. Torque the U-bolts to specification in stages in a cross pattern, then recheck after a few hundred kilometres and grease the nipples again once the pack has settled.

Find Fixed Pins for Your Vehicle

Select your vehicle to see the greasable fixed pin kits available for it, along with the complete shackle, pin and bushing packages. Every Whiteline component is backed by our warranty, a fitment guarantee and 60 day returns.