Technical Article for 31360646 Control Arm Bushing

1. Role of the Control Arm Bushing in Volvo Front Suspension

The control arm bushing is the elastic joint that connects the front lower control arm to the vehicle body or subframe. For modern Volvos such as S60, S90, V60, V90, XC60 and XC90, it is a key component for NVH, handling stability and long-term durability.

• It isolates road shocks and vibration from the cabin.

• It keeps the wheel geometry stable under braking, acceleration and cornering.

• It prevents metal-to-metal impact between the arm and body, protecting the chassis.

When the bushing fails, the driver will feel noise, vibration, harshness, vague steering and poor high-speed stability – even if shocks and tires are still in good condition.

2. OEM 31360646 – Product Overview

31360646 is a genuine Volvo Suspension Control Arm Bushing (Left, Right, Front) used on many SPA-platform models:

• Sedans & wagons

• Volvo S60

• Volvo S90 / S90L

• Volvo V60

• Volvo V90 and V90 Cross Country

• SUVs / crossovers

• Volvo XC60

• Volvo XC90 (2016–2024, various engines).

Typical position:

• Front suspension, front lower control arm, left and right;

• Usually the outer or front bushing of the arm, depending on the exact arm design.

In the aftermarket, 31360646 is sometimes listed together with:

• 31451003 – front suspension bushing kit

• 32246809 – front bushing set or related components

Hebei Huami’s replacement solution is engineered as an OEM-equivalent Volvo suspension bushing, with matching dimensions and installation angles.

3. Construction and Materials

The 31360646 control arm bushing is a typical rubber-metal bonded bushing:

• Inner sleeve

• Steel tube that clamps to the subframe via a bolt;

• Precisely machined for accurate fit and preload.

• Outer sleeve

• Steel shell press-fitted into the control arm;

• Surface roughness and roundness are controlled to ensure stable pressing force.

• Rubber damping layer

• Specially formulated rubber between inner and outer sleeves;

• Geometrical voids or slots are used to tune stiffness in different directions (soft longitudinally, stiffer laterally).

Rubber compounds (NR / NBR / EPDM)

Hebei Huami develops its own rubber compounds for suspension components:

• NR (Natural Rubber) – excellent dynamic properties and resilience, ideal for highly dynamic control arm bushings;

• NBR (Nitrile Rubber) – improved oil and fuel resistance, suitable for contaminated under-body environments;

• EPDM – outstanding ozone and aging resistance with good high-temperature capability.

Typical hardness: Shore A 60–75, designed to balance comfort with handling. Operating temperature: around –40°C to +100°C, with good resistance to wear, tear and compression set.

Surface treatment and bonding

• Shot-blasting / sand-blasting to clean the sleeves;

• Phosphate, e-coat or Zn-Ni plating to improve salt-spray corrosion resistance;

• Primer + cover adhesive system to achieve strong chemical bonding during vulcanization;

• Tight process control over temperature, pressure and curing time to ensure consistent cross-linking and long-term durability.

Leveraging its in-house compound mixing and rubber testing platforms, Hebei Huami can tune the bushing to specific NVH and durability targets required by distributors or fleet customers.

4. Common Failure Symptoms of 31360646 Bushings

When the control arm bushing ages or cracks, you may notice:

4.1 Noise and vibration when steering or over bumps

• Clunking or knocking noise when driving over speed bumps;

• Creaking noise when turning the steering wheel at low speed;

• Steering wheel vibration on rough surfaces.

4.2 Nose-dive and pulling under braking

• Pronounced nose-dive during hard braking;

• Car pulls to one side, especially during emergency stops;

• Longer perceived braking distance and unstable body attitude.

These issues are caused by excessive movement of the lower control arm when the bushing no longer controls longitudinal forces effectively.

4.3 Vague handling, cracks and debonding

• Vague steering feel and poor high-speed straight-line stability;

• Uneven tire wear on inner or outer edges;

• Visible cracks, missing rubber sections or debonding between rubber and metal, sometimes with the inner sleeve shifted off-center.

Once debonding or heavy cracking is visible, replacement is strongly recommended.

4.4 Simple ways to judge if replacement is needed

For workshops and fleet managers:

1. Visual inspection

• Lift the car and remove the front wheel;

• Inspect the bushing with a lamp for cracks, swelling, rubber loss or misalignment.

2. Lever test (carefully)

• Use a pry bar to gently move the control arm;

• Excessive free play or dull knocking usually indicates bushing wear.

3. Road test

• Low-speed steering over small bumps to listen for noise;

• Highway driving to check for pulling or constant steering correction.

If several of these symptoms appear together, planning an XC60 XC90 bushing replacement or full front-suspension inspection is the safe choice.

5. Installation and Maintenance Guidelines

The following is a general guide. Always refer to the official Volvo workshop manual and use proper tools.

5.1 Removing the control arm

1. Park the car on a flat surface and apply the parking brake;

2. Lift the vehicle and remove the front wheel;

3. Support the lower control arm to prevent sudden spring extension;

4. Disconnect the ball joint or related links from the steering knuckle;

5. Remove the front and rear control arm mounting bolts;

6. Take the lower control arm assembly off the vehicle.

5.2 Pressing out and installing the bushing

1. Use a hydraulic press and suitable adapters to press the old bushing out along the arm axis;

2. Clean the bore and check for deformation or corrosion;

3. Confirm the orientation and clocking of the new 31360646 bushing according to OE markings;

4. Slowly press the new bushing in, ensuring correct depth and no tilting.

5.3 Bolt torque and static preload

• Re-install the control arm and loosely fit all bolts;

• Lower the vehicle or support the arm so that the suspension sits at normal ride height;

• Only then perform final tightening to the specified torque, so that the rubber is not pre-twisted at rest.

Typical torques (placeholders – refer to Volvo data):

• Front lower control arm front bushing bolt: XX–XX Nm

• Front lower control arm rear bushing bolt: XX–XX Nm

• Ball joint nut / bolt: XX–XX Nm

Incorrect tightening with the suspension hanging can significantly shorten bushing life.

5.4 Maintenance interval

• Passenger vehicles: inspect every 40,000–60,000 km or 2 years;

• Fleet / commercial operation: inspect every 20,000–30,000 km;

• After severe pothole impact or curb strike, perform an extra inspection and a 4-wheel alignment.

6. Hebei Huami New Material – Manufacturing Advantages

Hebei Huami New Material Technology Co., Ltd. is a leading Chinese manufacturer of special rubber and engineering plastics, with strong capabilities in automotive suspension bushings. The company:

• Was founded in 1998 in Renze Economic Development Zone, Xingtai, Hebei;

• Is a national “Specialized and New – Key Little Giant” enterprise and listed on the Beijing Stock Exchange (code 836247);

• Employs over 600 people, including more than 100 R&D staff, and holds 47 authorized patents;

• Has passed ISO9001, IATF16949, ISO14001, ISO45001, GJB9001C, AS9100D and other management system certifications, and obtained China Customs AEO high certification and TUV approvals;

For control arm bushings and other suspension components, Huami offers:

• In-house rubber compounding with high-damping, low compression-set formulas;

• Precision mold design and automated molding, trimming and inspection;

• Comprehensive testing (hardness, tensile, tear, compression set, adhesion, dynamic fatigue, salt spray, high-/low-temperature aging);

• Stable delivery for more than 40 overseas customers across automotive, rail and machinery industries, and support for custom design and small-batch production.

This makes Hebei Huami a reliable partner for distributors, workshops and fleets looking for high-quality replacements for the Volvo control arm bushing 31360646.

7. Example Specification Table