1. The Role of the Leaf Spring Bushing in MAN Heavy Truck Suspension Systems

1.1 Flexible connection between leaf spring and frame/rocker, absorbing vibration and impact

In the steel leaf spring suspension of MAN TGA / TGX / TGS, the leaf spring bushing is pressed into the spring eye or rocker arm bore. Through the inner sleeve, rubber layer, and outer shell, it creates:

• A flexible connection between the leaf spring and the frame/rocker arm

• An elastic interface instead of metal-to-metal contact

• A way to absorb road impacts and vibrations when the truck passes potholes, speed bumps, or runs at high speed

For any heavy truck suspension bushing, this flexible connection is fundamental to improving ride comfort and protecting the chassis structure.

1.2 Maintaining axle alignment and vehicle stability

Leaf springs not only carry the vehicle weight; they also help locate the axle.

The leaf spring bushing, through coordinated deformation of the rubber and metal sleeves, controls small movements of the axle in:

• Longitudinal direction

• Lateral direction

• Rotational (twisting) direction

When the bushing is worn or delaminated, you may see:

• Axle shifting forward/backward or sideways

• Nose-diving during braking

• A “floating” or “twisting” feeling when driving at high speed or fully loaded

A healthy MAN leaf spring bushing is therefore critical to keeping the axle where the chassis designer intended it to be.

1.3 Reducing metal wear and improving ride comfort

The leaf spring, chassis brackets, and rocker arms are mostly metal parts. Without a proper bushing – or with a failed one – you will see:

• Metal-to-metal contact, causing oversized bores and accelerated wear

• Strong vibration transmitted directly to the chassis and cab

• Higher fatigue on the driver during long working hours

• Long-term negative impact on instrumentation, wiring, bodywork, and cargo body

A high-quality MAN leaf spring bushing significantly reduces these hidden costs and keeps the vehicle more comfortable and reliable in heavy-duty transport.

1.4 Designed for heavy loads and high-frequency vibration

MAN TGA / TGX / TGS trucks are widely used in:

• Long-haul logistics

• Construction and engineering transport

• Cold chain and container transport

• Regional distribution and mixed road conditions

Typical operating conditions are:

• Long periods at or near full load

• High mileage and high-frequency vibration

• Rough roads: national highways, ports, construction sites, mining areas, etc.

This imposes stringent requirements on the shear strength, compression performance, and fatigue life of the leaf spring bushing.

If you use a bushing designed for lighter vehicles, it may crack, tear, or delaminate in a short time. Choosing a true heavy truck suspension bushing specifically engineered for this environment is key to reducing downtime and total cost of ownership.

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2. Product Overview: MAN OEM 81437220070 Leaf Spring Bushing

2.1 Applicable models

This bushing is mainly designed for:

• MAN TGA series

• MAN TGX series

• MAN TGS series

It is used to replace the original OEM: 81437220070 leaf spring bushing, one of the common wear parts in the rear suspension of these heavy trucks.

2.2 Typical installation positions

On these models, the MAN leaf spring bushing 81437220070 is usually installed at:

• The front and rear spring eyes of the leaf spring

• Connection points between the leaf spring and rocker arm/equalizer

• In some designs, as the pivot bushing for balance arms or rods connecting the axle to the frame

Exact positions should be confirmed with the vehicle VIN, parts catalog, and repair manual, but in all cases, this part functions as a pivot bushing in the leaf spring suspension system.

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3. Structure and Materials: Heavy-Duty Rubber-Metal Leaf Spring Bushing

3.1 Typical construction: inner sleeve / rubber layer / outer shell

A standard MAN leaf spring bushing (OEM 81437220070) generally consists of three elements:

• Inner sleeve

• Steel machined part, matching the bolt or pin

• Usually treated with phosphate and anti-rust oil for corrosion protection

• Rubber layer

• Bonded to the inner and outer sleeves through hot vulcanization

• Determines the bushing’s stiffness, damping, displacement capacity, and fatigue life

• Outer shell

• Press-fitted into the leaf spring eye or rocker arm bore

• Requires adequate strength and dimensional accuracy for stable fit

This rubber-metal leaf spring bushing design combines the load-carrying capacity of steel with the elasticity and damping of rubber, effectively absorbing vibration and shock.

3.2 Rubber compound selection: NR / BR / NBR / EPDM

Hebei Huami New Material selects the rubber compound according to operating conditions and customer requirements, for example:

• NR/BR systems

• Suitable for large deflection and high-frequency vibration

• Excellent elasticity and fatigue resistance

• NBR systems

• Better resistance to oils, diesel, and lubricants

• Suitable for oily and contaminated environments

• EPDM systems

• Excellent weather, ozone, and high/low temperature resistance

• Suitable for vehicles exposed to harsh outdoor conditions

For typical MAN TGA / TGX / TGS long-haul applications, Huami uses high-damping heavy-duty compounds that balance comfort, durability, and cost.

3.3 Shore A hardness and mechanical properties

To meet heavy truck suspension demands, the rubber hardness of the 81437220070 bushing is usually designed in the range:

• Shore A 65–80 (typical range)

• Can be tuned according to fleet operating conditions (mining, extreme cold, port operations, etc.)

Key performance indicators include:

• Abrasion resistance – to prevent rubber chunking or excessive wear

• Compression set resistance – to retain shape and elasticity after long-term compression

• Fatigue resistance – to withstand millions of cycles of shear, compression, and torsion without crack growth

3.4 Shear and compression performance under heavy loads

In service, the bushing is subject to:

• Axial compression

• Radial shear

• Torsional deformation

Hebei Huami New Material uses finite element analysis (FEA) and durability bench testing to optimize:

• Rubber geometry and thickness

• Metal sleeve design

• Compound formulation

The result is a bushing that:

• Provides appropriate movement and comfort under normal loads

• Resists tearing or delamination under peak or shock loads

• Maintains stable stiffness over high mileage and harsh cycles

3.5 Metal corrosion protection and rubber-metal bonding

To withstand salt spray, mud, and winter road conditions, the inner and outer sleeves usually receive:

• Anti-corrosion coating or plating

• Additional pre-treatment such as phosphating or shot blasting if needed

Rubber and metal are bonded using a professional adhesion system and controlled vulcanization process, effectively preventing:

• Relative slip between inner and outer sleeves

• Debonding at the rubber-metal interface

• Early delamination failures in heavy-duty service

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4. Common Failures and Symptoms (High-Search Topics)

In real-world use, the following issues are frequently searched and asked by fleets and workshops.

4.1 Leaf spring noise and cab vibration

Typical symptoms:

• “Creaking” or “squeaking” sounds when passing bumps or ramps

• Slight but noticeable cab vibration at speed

Possible causes:

• Aged and hardened rubber layer

• Excessive clearance between inner sleeve and bolt

• Outer shell turning or loosening in the leaf spring eye or rocker arm bore

4.2 Eccentric wear, twisting, cracks, and delamination

Visual inspection may reveal:

• Rubber worn more on one side, or clearly twisted

• Cracks on the rubber surface (longitudinal or transverse)

• Visible opening or peeling between rubber and metal edges

This indicates that the heavy truck suspension bushing is close to or at the end of its service life and should be replaced soon.

4.3 Vehicle pulling and inaccurate axle alignment

Symptoms include:

• Steering wheel needs constant correction when driving straight

• Abnormal or uneven tire wear

• Vehicle “pulls” to one side under braking

Besides checking front axle alignment and tires, inspect the leaf spring bushings. Worn bushings can cause axle position changes, leading to these issues.

4.4 Practical ways to determine whether the bushing needs replacement

Before MAN TGA bushing replacement, fleets and workshops can use the following steps:

1. Lift the vehicle or park it over a pit

• Ensure safe access to the suspension components

2. Visual inspection

• Check bushings at spring eyes and rocker arms for cracks, delamination, eccentric wear, or missing rubber pieces

3. Lever test

• Use a pry bar near the leaf spring end or rocker arm

• If there is obvious free play, excessive movement, or a “clicking” sound at the bushing, it is likely worn out

4. Measure clearance (for higher standards)

• Use feeler gauges or dial indicators to measure gaps or displacement

• Compare results with workshop or OEM guidelines

5. Combine with mileage

• For high-mileage long-haul trucks, a full suspension inspection is recommended every 200,000–300,000 km, with preventive replacement if necessary

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5. Installation and Maintenance: Practical Tips for MAN TGA Bushing Replacement

5.1 Basic removal and press-fit steps

1. Remove the leaf spring or rocker arm assembly

• Secure the vehicle, apply the parking brake, and follow safety procedures

• Mark positions and orientation of parts for correct reassembly

2. Remove the old bushing

• Use a hydraulic press or dedicated puller to push the old bushing out

• Avoid burning or heavy hammering, which can damage the spring eye or rocker arm bore

3. Clean and inspect the bore

• Remove rust and debris from the bore

• Check for ovality or oversize; repair or replace components if the bore is seriously out of round

4. Press in the new bushing

• Confirm that the bushing matches OEM: 81437220070 and is free of damage

• Apply appropriate lubricant if allowed by the manufacturer

• Use proper fixtures to ensure the bushing is aligned with the bore and press it in slowly and evenly

5. Reinstall the assembly

• Refit the leaf spring or rocker arm according to alignment marks

• Pre-tighten bolts without fully torquing them yet

5.2 Centering and installation orientation

• Some leaf spring bushings may have a specific orientation (eccentric design or asymmetric flanges). Always follow the MAN factory service manual and diagrams.

• Ensure that the outer shell’s projection on each side of the spring eye or rocker arm shoulder is within the specified range and not offset.

5.3 Tips to extend leaf spring bushing life

• Avoid long-term severe overload

• Clean mud and corrosive substances around the suspension regularly

• Replace bushings as soon as early cracks or hardening are found to prevent damage to spring eyes, brackets, and rocker arms

• Use high-quality MAN leaf spring bushing 81437220070 from reliable manufacturers to reduce early failures

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6. Manufacturing Advantages of Hebei Huami New Material

Heavy-Duty Rubber-Metal Bushing Specialist

Hebei Huami New Material Technology Co., Ltd. has been specialized in rubber compounds and rubber products for decades and offers strong capabilities in heavy truck suspension bushings.

6.1 30 years of rubber manufacturing experience

• Founded in the late 1990s, Huami has focused on special rubber compounds and rubber parts for automotive, construction machinery, rail, petroleum equipment, and other industries

• Hundreds of employees and dozens of authorized patents

• Participation in the drafting of several national and industry standards

This long industrial experience provides a solid foundation for the development and production of heavy truck suspension bushings.

6.2 Complete quality systems and international certifications

Huami has:

• IATF 16949 automotive quality management system

• ISO 9001, ISO 14001, ISO 45001 and other management systems

• AEO Advanced Certification for customs, as well as TÜV-related certifications

For global fleets and distributors, this means:

• Traceable quality

• Stable and consistent product performance

• More efficient cross-border logistics and customs clearance

6.3 Self-developed high-damping / long-life rubber compounds, optional heavy-duty versions

For harsh applications such as mining, ports, oilfields, and cold chain, Huami can provide:

• High-damping compounds to improve vibration isolation

• Rubber formulations with enhanced abrasion and fatigue resistance

• Thicker rubber sections or reinforced structural designs to increase life beyond OE specification where needed

This is especially valuable for fleets seeking longer replacement intervals than standard OEM parts.

6.4 High-precision tooling and dimensional consistency

• In-house tool design and manufacturing with CNC machining centers

• Tight control of inner and outer diameter and rubber thickness

• Statistical Process Control (SPC) and in-line inspection to keep batch-to-batch variation very low

This dimensional consistency leads to easier pressing, fewer noises after installation, and more predictable behavior across large fleets.

6.5 Comprehensive testing and validation capabilities

Huami’s laboratory can perform:

• Rubber hardness, tensile strength, and tear strength tests

• Compression set, rubber-metal bonding strength, abrasion tests

• Salt spray, oil resistance, high/low temperature tests

• Heavy-duty fatigue tests simulating real road conditions

From raw materials to finished leaf spring bushings, every stage is validated to ensure that MAN 81437220070 leaf spring bushings perform reliably in actual service.

6.6 Flexible supply and stable lead time

• Support for sample development, small pilot batches, and large-scale production

• Adaptable to OEM projects, aftermarket distribution, and direct fleet supply

• With the AEO Advanced Certification advantage, Huami provides stable lead times and smooth export processes

For international distributors and large fleets, this translates into better supply security and lower inventory risk.

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7. Technical Specification Table (Template)

The table below is a web display template. Please fill in exact dimensions and data according to drawings and measurements.

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8. FAQ 

Q1: What is the typical service life of MAN leaf spring bushing OEM 81437220070?
A: Under normal road conditions and regular maintenance, the 81437220070 leaf spring bushing on MAN TGA, TGX, and TGS trucks can usually run 200,000–400,000 km. For severe applications such as mining or off-road use, inspections and MAN TGA bushing replacement should be carried out more frequently.

Q2: What are the common symptoms that indicate the MAN leaf spring bushing needs replacement?
A: Typical symptoms include knocking or creaking noises from the spring area, increased cab vibration, vehicle pulling or unstable braking, and visible cracks, rubber peeling, or eccentric wear on the bushing. Any of these signs mean the bushing should be inspected and replaced in time.

Q3: Can a universal heavy truck suspension bushing be used instead of OEM 81437220070?
A: It is not recommended. Even if the size looks similar, a universal heavy truck suspension bushing may affect axle alignment, noise level, and durability. Always select parts that match OEM 81437220070 or verified cross reference numbers.

Q4: What should I pay attention to during MAN TGA bushing replacement?
A: Use a proper press tool, do not burn or hammer the bushing violently, clean the spring eye or rocker arm bore thoroughly, align the bushing correctly, and tighten bolts with the truck on its wheels at normal ride height, using the specified torque values.

Q5: What are the advantages of Hebei Huami New Material MAN leaf spring bushings?
A: Hebei Huami New Material uses heavy-duty rubber compounds, high-precision tooling, and full laboratory testing (hardness, tensile, adhesion, fatigue, etc.) to provide long life and stable performance for MAN heavy truck suspension systems. Customized and reinforced versions are also available for harsher conditions.

Q6: Can the hardness of MAN leaf spring bushing 81437220070 be customized?
A: Yes. Within a reasonable Shore A range, Hebei Huami New Material can adjust rubber hardness and compound formulation for different applications such as mining, cold chain, or port logistics, balancing comfort and durability.

Q7: How can logistics fleets reduce the overall cost of their leaf spring bushings?
A: Choose high-quality bushings, establish mileage- and condition-based inspection schedules, avoid prolonged overloading and aggressive driving, and work with suppliers who are certified (IATF 16949, TÜV, AEO Advanced Certification) and experienced in heavy truck suspension bushings.

Q8: Does Hebei Huami New Material support samples and small batch trial orders?
A: Yes. The company can develop and supply samples and small batches of MAN 81437220070 leaf spring bushings based on drawings or original samples, then scale up to mass production with stable lead times and technical support during field trials.