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The structural integrity of a truck’s leaf spring suspension system relies on the secure and precise alignment of its components, with the center bolt playing a fundamental anchoring role. As a critical fastener within the extensive catalog of durable SANY parts, the OEM 131699000040A Spring Center Bolt is engineered for maximum strength and reliability. This genuine component, identified by the specific part number 131699000040A, serves as the central pivot and locating pin for multi-leaf spring assemblies.
It ensures the individual leafs remain perfectly aligned under load, prevents lateral shifting, and provides the primary attachment point between the spring pack and the axle or mounting bracket. Choosing the authentic 131699000040A bolt is a crucial step in maintaining proper suspension geometry, ride height, and overall vehicle safety, directly impacting handling stability and the longevity of other suspension components on your SANY truck.
Spring Center Bolt
Центральный болт рессоры
Perno Central del Resorte
The SANY 131699000040A is not a standard bolt; it is a specialized fastener designed exclusively for securing leaf spring assemblies. In a multi-leaf spring pack, the individual steel leaves must work in unison as a single, progressive unit. The center bolt is inserted through precisely aligned holes in the center of each leaf, clamping the entire stack together. Its primary function is to maintain the fore-aft alignment of the leaves, preventing them from sliding or fanning out under the twisting and shearing forces experienced during braking, acceleration, and cornering.
Furthermore, the head and threaded end of the 131699000040A bolt protrude from the spring pack. These protruding sections engage with the mounting pad on the axle (for the front) or with the shackle and hanger brackets, physically locating the spring on the vehicle’s chassis. This precise location is critical for maintaining correct axle placement, wheel alignment, and overall vehicle ride height. A failed or sheared center bolt can allow the spring leaves to shift, leading to axle misalignment, abnormal tire wear, a noticeable sag in the vehicle’s stance, and potentially dangerous handling characteristics.
The bolt is subjected to immense shear forces, compression, and cyclic stress. Therefore, the genuine 131699000040A is manufactured from high-tensile steel and heat-treated to withstand these demands without stretching, bending, or fracturing. Replacing a worn or damaged bolt with the authentic 131699000040A during spring service or suspension repair is a fundamental safety procedure that restores the structural cohesion of the suspension system.
The 131699000040A bolt is forged from medium carbon alloy steel, such as Grade 8.8 or 10.9 equivalent, and undergoes quenching and tempering processes. This gives it an exceptional strength-to-weight ratio and superior resistance to shear and tensile failure.
Threads are cold-rolled rather than cut, which work-hardens the material and creates a smoother, stronger thread profile with superior fatigue resistance. This ensures the nut can be torqued accurately and remains secure under vibration.
The unthreaded shank section is precision-ground to a consistent diameter, ensuring a snug fit through all leaf eyes without slop. A well-defined shoulder under the head provides a positive seating surface against the top leaf.
A robust zinc plating or yellow dichromate finish is applied to the 131699000040A bolt. This provides excellent protection against rust and corrosion from road salt, moisture, and chemicals, extending service life.
Often features a flanged hex head. The flange distributes clamping force over a wider area on the spring leaf, and the hex design allows for secure engagement with standard wrenches or sockets during installation.
The entire design of the 131699000040A, from its material grade to its shank diameter, is calculated to exceed the shear loads imposed by the sprung weight of the vehicle and dynamic forces, preventing catastrophic failure.
Detailed OEM specifications for the Spring Center Bolt. Dimensions are critical for correct leaf spring assembly.
| Parameter | Specification | Details / Unit |
|---|---|---|
| OEM Part Number | 131699000040A | Genuine SANY Identification |
| Component Name | Spring Center Bolt / Leaf Spring Center Pin | Primary Function |
| Brand | SANY | Manufacturer |
| Material Grade | Alloy Steel, Grade 10.9 (Metric) | High tensile strength class |
| Thread Size & Pitch | M16 x 2.0 (Example – Model Specific) | Common for heavy truck springs |
| Shank Diameter (D) | 16 mm (Matches thread major diameter) | Precision ground |
| Overall Length (L) | 150 mm – 200 mm (Approx., varies) | Must suit spring pack thickness |
| Head Style | Hex Flange Head (19mm or 22mm) | For wrench/socket engagement |
| Proof Load | ~83,000 psi (Grade 10.9) | Minimum stress before yield |
| Tensile Strength | ~150,000 psi (Grade 10.9) | Maximum stress before fracture |
| Surface Finish | Zinc Plated, Yellow Dichromate | Corrosion protection |
| Included Components | Bolt and Hex Flange Nut (Often) | Complete fastener set |
A compromised 131699000040A spring center bolt can lead to a cascade of suspension problems that affect safety, handling, and component life. The most immediate failure mode is shearing of the bolt shank due to excessive shear stress or metal fatigue. This allows the leaf spring pack to separate or shift laterally, causing a sudden and dramatic change in vehicle ride height and alignment. The axle may become mispositioned, leading to severe dog-tracking and unpredictable steering.
Even before complete failure, a stretched or undersized bolt can allow the spring leaves to move independently. This causes a clunking or banging noise over bumps as the leaves slap together, and accelerates wear on the leaf eyes and the bolt itself. The resulting misalignment alters the suspension’s geometry, causing rapid and uneven tire wear, often seen as cupping or scalloping on the tread. Furthermore, a loose spring pack cannot properly absorb road shocks, transferring more impact force to the chassis and other suspension components, potentially damaging shock absorbers, U-bolts, and spring hangers.
Using an incorrect bolt—such as one with a smaller diameter, lower grade material, or insufficient length—is equally dangerous. It may not provide the necessary shear strength, leading to premature failure under normal loads. Therefore, installing the correct, genuine 131699000040A bolt with the proper torque specification is a non-negotiable safety procedure. Regular inspection during suspension service for signs of bending, corrosion, or thread damage on the center bolt is a key preventive maintenance practice to avoid these costly and hazardous outcomes.
Ensure all spring leaves are clean, properly aligned, and free of debris. The center holes of all leaves must be in perfect alignment. Insert the new 131699000040A center bolt through the stack from the top (usually head down, threaded end up). The bolt should slide freely through all leaves without forcing, indicating good alignment. Place the spring pack in a press or vise to compress the leaves slightly, ensuring all leaves are seated flat against each other at the center. While compressed, install the provided flange nut onto the threaded end of the bolt. It is critical to use the correct nut, typically a graded flange nut, and not a standard nut.
Using a calibrated torque wrench, tighten the nut to the specification provided by SANY for the specific truck model. This torque is typically significant (e.g., 200-300 Nm for an M16 bolt) to ensure the spring pack is clamped tightly enough to prevent leaf movement but not so tight as to risk damaging the threads or distorting the leaves. Do not rely on impact wrenches for final torque. After torquing, the bolt’s threads may protrude; this is normal. The assembled spring pack can then be installed on the vehicle.
Important: Spring assembly and installation involve high clamping forces and are critical for vehicle safety. This work should be performed by a qualified technician familiar with heavy-duty suspension systems, using the correct tools and adhering strictly to the vehicle manufacturer’s torque specifications.
The SANY 131699000040A spring center bolt is designed for specific leaf spring applications on various SANY truck models, including dump trucks, mixers, and haulage vehicles. Its dimensions—shank diameter, length, and thread specification—are precisely matched to the leaf spring pack’s design thickness and the size of the mounting hardware. Using the exact OEM part number ensures compatibility with the spring eye diameter and the corresponding axle pad or shackle bracket.
Leaf springs are not generic; they are engineered for specific load capacities and suspension travel. A center bolt that is too short will not engage the nut properly, while one that is too long may bottom out or interfere with other components. Similarly, a bolt with a smaller diameter will allow movement within the leaf eyes, causing wear and eventual failure. The genuine 131699000040A is validated for the shear loads and environmental conditions expected in its specific application. Always cross-reference this part number with the truck’s VIN or detailed parts catalog to confirm it matches the spring part number and vehicle configuration.
Furthermore, the bolt’s material grade and finish are chosen to work in tandem with the spring leaves and other fasteners (U-bolts, nuts). Using a lower-grade bolt can create a weak point in an otherwise robust assembly. For fleet maintenance, standardizing on the genuine 131699000040A for relevant vehicles ensures consistent repair quality, maintains proper suspension performance, and supports the overall durability and safety standards expected from SANY equipment.
This bolt is a critical safety fastener. Substituting it with an inferior part risks the integrity of the entire suspension assembly.
The 131699000040A is manufactured to a certified high-tensile grade (e.g., 10.9), guaranteeing the necessary shear and tensile strength. Generic bolts may not meet these specs, posing a failure risk.
Guarantees the exact shank diameter and length for a perfect fit through the spring leaves and proper engagement with the nut, eliminating movement that causes wear and noise.
Suspension failure can lead to loss of vehicle control. Using the genuine 131699000040A mitigates this risk and ensures compliance with safety standards and potential liability requirements.
The genuine 131699000040A is backed by SANY’s parts warranty. Its correct use protects your investment by preventing secondary damage to springs, U-bolts, and tires caused by misalignment.
The SANY 131699000040A Spring Center Bolt is a fundamental component that holds the leaf spring suspension system together, literally and figuratively. Its role in maintaining alignment, handling, and safety is profound. Opting for a non-genuine or substandard bolt introduces an unacceptable risk of failure that can compromise vehicle stability and lead to extensive secondary damage.
For maintenance professionals, fleet managers, and owner-operators who prioritize safety and reliability, specifying the authentic SANY part number 131699000040A is the only responsible choice. It is the definitive fastener engineered to provide the strength and precision required to keep your SANY truck’s suspension securely anchored and performing optimally under all load conditions.
Anchor your suspension in reliability. Choose SANY Genuine Parts.
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