How to properly install cushions on truck springs: step-by-step instructions with photos and tips

Why are cushions on springs needed and when to change them?

Leaf springs are small but critical components of a truck's suspension that dampen vibrations between the frame and axle. Made from high-strength rubber or polyurethane, they prevent metal-to-metal contact between parts, reduce noise and extend the life of the entire chassis. Over time, the cushions wear out: the rubber cracks, loses its elasticity or completely delaminates. If you notice knocking in the suspension when driving over bumps, uneven tire wear, or you feel like your truck has become less stable on the road - these are sure signs that the cushions need replacing.

The average lifespan of quality pillows is 80–120 thousand km, but on trucks operated in difficult conditions (transportation of heavy loads, off-road driving, frequent overloads), this period is reduced to 50–70 thousand km. Manufacturers such as Scania, Volvo or MAN, it is recommended to check the condition of the airbags at every scheduled maintenance, especially if the car is working on construction sites or in quarries. Ignoring the problem is fraught not only with discomfort, but also damage to spring leaves or even frame deformation.

It is important to understand that pillows come in different types:

• 🔹 Standard rubber - the most common, budget, but less durable.
• 🔹 Polyurethane - more expensive, but withstand heavy loads and last longer (up to 150 thousand km).
• 🔹 With metal inserts - for heavy trucks (for example, DAF XF or Mercedes Actros).

Before purchasing new pillows, be sure to check truck make and model, and also spring type (parabolic, multi-leaf). A discrepancy in even one parameter will lead to incorrect operation of the suspension.

Preparing for Installation: Tools and Safety Precautions

Installing cushions on springs is a task that requires not only a set of tools, but also compliance with safety precautions. First of all, secure the truck on a flat, hard-surfaced area. Use wheel chocks under the wheels and be sure to raise the frame hydraulic stands - a jack is not suitable here, as it can slip under load. The minimum lifting height should allow the bridge to be easily dismantled.

List of required tools:

• 🔧 Wrenches (snap-on and horn-type, sizes depend on the truck model).
• 🔧 Socket heads with extension (for hard-to-reach bolts).
• 🔧 Torque wrench (to maintain the tightening torque).
• 🔧 Crowbar or crowbar (for spreading spring leaves).
• 🔧 WD-40 lubricant or an analogue (for unscrewing soured bolts).
• 🔧 New pillows and fasteners (bolts, nuts, washers).

⚠️ Attention: Never work under a truck that is supported only by a jack! Even if you use two jacks, their support points may move when the load is removed from the springs. Always duplicate the lift certified stands with a reserve of carrying capacity.

Before starting work take pictures of the location of all the parts - this will help to avoid errors during reassembly. Pay special attention pillow markings: The top and bottom may differ in shape. For example, on trucks Renault Magnum The top cushions have a bulge for centering, while the bottom ones are flat.

Step-by-step instructions for dismantling old pillows

Start with loosening the mounting bolts spring stepladders. Do not remove them completely - first you need to unload the spring. To do this:

1. Raise the truck axle until the spring begins to sag.
2. Place the stands under the frame (not under the bridge!).
3. Using a pry bar, carefully spread the spring sheets and secure them with ties or wire.

Now you can completely unscrew the bolts of the stepladders and remove them. Please note: on some models (eg Scania R420) stepladders are attached through eccentric bushings — their position must be remembered or marked with a marker so as not to disturb the geometry of the suspension during assembly.

Next, remove the old pillows:

• 🔨 If the pillow “sticks” to a stepladder or spring, use rubber hammer or a wooden spacer to knock it down.
• 🔨 Clean the seats from dirt and rust wire brush.
• 🔨 Check the status spring leaves for cracks or corrosion.

⚠️ Attention: On trucks with air suspension (for example, Volvo FH16) before dismantling the springs, be sure to release the pressure in air cylinders! Otherwise, when removing the stepladders, the bridge may drop suddenly, causing injury or damage to parts.

A critical mistake many mechanics make: not checking the eccentric bushings of stepladders. If they are not adjusted after installing new cushions, the spring will work at an angle, which will lead to uneven tire wear and knocking after 5-10 thousand km.

The seats have been cleaned of rust and dirt|

Spring leaves checked for cracks|

The initial position of the stepladders and bushings was photographed|

New bolts and nuts prepared (if necessary)|

Air suspension depressurized (if applicable) -->

Installing new pillows: nuances and common mistakes

Start with checking new pillows for compliance with the truck model. Even if they look similar, they may differ:

• 📏 Thickness (for example, for Mercedes-Benz Arocs The front airbags are 5 mm thicker than the rear ones).
• 📏 Hole shape (oval or round).
• 📏 Presence of metal inserts (required for trucks with a carrying capacity of over 20 tons).

Installation occurs in reverse order:

1. Place the new pad on the spring, aligning the holes.
2. Install the stepladder and screw in the bolts manually (no puff!).
3. Remove the spring leaf clamps and slowly lower the axle, ensuring alignment.
4. Tighten the bolts criss-cross torque wrench (the tightening torque is indicated in the manual, usually 120–180 Nm).

Typical installation errors:

• ❌ Bolt tightening — leads to deformation of the cushions and their premature wear.
• ❌ Reusing old bolts — the threads on them are often worn out, which can lead to self-unscrewing.
• ❌ Hole misalignment - if the pillow does not fit tightly, it will “walk” and quickly collapse.

Error	Consequences	How to avoid
Installing pillows upside down	Incorrect operation of the suspension, knocking	Check the markings (usually there is an arrow or the inscription "TOP")
Using lubricant on rubber surfaces	Rubber swells and loses elasticity	Lubricate only metal parts (bolts, bushings)
Unchecked alignment of stepladders	Spring misalignment, uneven tire wear	Use a laser level or template

Adjusting the suspension after replacing the cushions

Replacing the pillows is only half the job. After installation you need adjust suspensionto ensure correct geometry and even load distribution. Start by checking:

• 📐 Body heights above the axis (must be the same on both sides).
• 📐 Spring angle (use a protractor or a special template).
• 📐 Tightening all fasteners (check again after 100 km).

On trucks with air suspension additionally required:

1. Bleed the system to operating pressure (usually 6–8 bar).
2. Check the tightness of the connections (air leaks will lead to sagging of the suspension).
3. Calibrate level sensors (if present).

Fine adjustment may require wheel alignment stand, especially if you notice that the truck is "pulling" to the side. On models with dependent suspension (for example, Kamaz 6520) the adjustment comes down to adjusting the length of the rods, and on Scania or Volvo with independent suspension, the control arms will need to be adjusted.

⚠️ Attention: If after replacing the pillows there is play in the steering, this may indicate that the bridge is not aligned correctly. In this case, it is necessary to dismantle the stepladders again and align the spring according to the template.

How to check the quality of installation without a stand?

After a test drive (5-10 km), stop and check:

1. Temperature of the pads - if they are hot, it means there is friction due to improper installation.

2. Presence of knocking noises when rocking the truck manually.

3. Uniformity of tread wear (after 500 km).

If at least one of the points is called, repeat the adjustment.

Choice of pillows: rubber vs polyurethane

When choosing materials for pillows, many drivers face a dilemma: rubber or polyurethane? Let's look at the pros and cons of each option.

Rubber pads:

• ✅ Cheaper at 30–50%.
• ✅ Vibrations are dampened more gently (more comfortable for the driver).
• ✅ Easier to find in stores.
• ❌ They wear out faster (especially under high loads).
• ❌ Lose elasticity at low temperatures.

Polyurethane cushions:

• ✅ Service life in 2–3 times longer.
• ✅ Resistant to oils, fuels and chemicals.
• ✅ Do not deform under heavy loads.
• ❌ More expensive (the price can reach 5–7 thousand rubles. per set).
• ❌ Vibrations are transmitted more harshly to the body.

For construction equipment (dump trucks, concrete trucks) polyurethane cushions with metal inserts are optimal - they can withstand shock loads during unloading. For mainline tractors (for example, DAF XT) high-quality rubber cushions from trusted brands, such as Lemforder or TRW.

Please note pillow color:

• 🟢 Greens - standard hardness.
• 🔴 Reds — reinforced (for severe conditions).
• 🟡 Yellow — for extreme temperatures (arctic version).

Pillow Maintenance: How to Extend Their Lifespan

Even the highest quality pillows will last longer if you follow a few simple rules:

• 🚛 Control the load — avoid constant overloads (especially important for dump trucks).
• 🚛 Wash the pendant after driving through mud or salt, the reagents destroy the rubber.
• 🚛 Check fasteners every 10 thousand km (ladder bolts can self-unscrew).
• 🚛 Lubricate metal parts (bushings, bolts) with graphite lubricant.

Signs that pillows need replacing:

• 🔊 Knock when passing speed bumps.
• 🔊 Vibration on the steering wheel when accelerating.
• 🔊 Uneven tire wear (especially along the inner edge).
• 🔊 Suspension sag on one side.

If you operate a truck in extreme conditions (quarries, highlands, Far North), consider the option reinforced pillows with metal reinforcement. They are more expensive, but pay for themselves due to the increased resource. For example, for Ural Next or Kamaz 6595 Manufacturers offer special “Arctic” kits that are resistant to temperatures up to −50°C.

FAQ: Frequently asked questions about spring cushions

Is it possible to drive with a broken spring cushion?

For a short time (up to 500 km) - yes, but with caution. Driving for a long time without an airbag leads to:

• 🔧 Accelerated wear of spring leaves (they rub against each other).
• 🔧 Damage to the fastening bolts of stepladders.
• 🔧 Risk of frame deformation due to strong impacts.

At a higher speed 60 km/h possible yaw effect — the truck becomes uncontrollable.

How often do spring cushions need to be changed?

Service life depends on operating conditions:

Terms	Rubber cushions	Polyurethane pillows
Long-haul transportation	80–100 thousand km	120–150 thousand km
Construction work	40–60 thousand km	80–100 thousand km
Career exploitation	20–30 thousand km	50–70 thousand km

Signs of wear: cracks, rubber delamination, deformation.

Is it possible to install polyurethane cushions instead of rubber ones?

Yes, but keep in mind:

• 🔹Polyurethane tougher, so comfort will decrease (more vibrations in the cabin).
• 🔹 Precise fit required - polyurethane does not “fit” as tightly as rubber.
• 🔹 Not all truck models support such a replacement (check the manual for details).

For Scania and Volvo produce special polyurethane kits, and for Kamaz or MAZ Seats may require modification.

What happens if you don't change pillows on time?

Consequences of ignoring the problem:

1. Destruction spring leaves (cracks, breaks).
2. Deformation mounting bolts and stepladders.
3. Damage bridge due to geometry displacement.
4. Deterioration controllability (the truck “drives” to the side).
5. Elevated tire wear (up to 30% faster).

In critical cases it is possible spring break on the move, which will lead to an accident.

What are the best pillows for a dump truck?

For dump trucks (Howo, Shacman, Kamaz 6520) are optimal:

• 🔹 Polyurethane cushions with metal inserts (for example, SASIC 850123).
• 🔹 Reinforced rubber marked "Heavy Duty".
• 🔹 Double layer pillows (for the rear axle).

Important: after replacement, adjust suspension advance angle, since dump trucks often operate with uneven loads.