Pushrod: Diameter 6-12 mm, Hardness 35-45 HRC

Component Specifications

Definition

A pushrod is a precision-engineered cylindrical component within a brake master cylinder assembly that serves as the primary force transmission element. It converts the linear mechanical force applied by the driver's foot on the brake pedal into hydraulic pressure by actuating the master cylinder piston. Typically mounted between the brake pedal lever and the master cylinder piston, it operates under high mechanical stress and must maintain strict dimensional accuracy to ensure proper brake system function and pedal feel.

Working Principle

The pushrod operates on the principle of direct force transmission through rigid linkage. When the brake pedal is depressed, the pedal lever pivots, pushing the pushrod forward. This linear motion is transferred directly to the master cylinder piston, which then compresses the brake fluid in the primary chamber. The pushrod must maintain alignment and minimal deflection to ensure efficient force transfer without energy loss, contributing to precise brake modulation and response.

Materials

Typically made from medium-carbon steel (e.g., AISI 1045, 4140) or alloy steel, often heat-treated (quenched and tempered) to achieve a hardness of 35-45 HRC for strength and wear resistance. Some high-performance or corrosion-resistant applications may use stainless steel (e.g., 17-4PH) or aluminum alloys with hardened tips.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Length	100-300 mm (varies by vehicle)
Diameter	6-12 mm
Hardness	35-45 HRC
Thread Type	M8x1.25, M10x1.5, or vehicle-specific
Surface Finish	Ground or polished, Ra ≤ 1.6 μm
Straightness Tolerance	≤ 0.1 mm over length

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 4038, DIN 743, SAE J429

Parent Products

This component is used in the following industrial products

Brake Master Cylinder

A brake master cylinder is a critical component in hydraulic braking systems. It converts mechanical force from the brake pedal into hydraulic pressure, which is then distributed to the wheel cylinders or calipers to apply braking force.

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Engineering Analysis

Risks & Mitigation

Fatigue failure due to cyclic loading
Corrosion leading to seizing or reduced strength
Improper length causing brake drag or insufficient pedal travel
Misalignment inducing side loading and premature wear

FMEA Triads

Trigger: Material fatigue from repeated stress cycles
Failure: Fracture or permanent deformation
Mitigation: Use fatigue-resistant steels, apply shot peening, and implement regular inspection protocols

Trigger: Corrosion in harsh environments
Failure: Reduced diameter, pitting, or seizing in bushings
Mitigation: Apply corrosion-resistant coatings (e.g., zinc plating, phosphate), use stainless steel in critical applications

Trigger: Improper installation or adjustment
Failure: Incorrect brake pedal feel, reduced braking efficiency
Mitigation: Follow OEM torque specifications, use alignment tools during assembly, verify free play adjustment

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Dimensional tolerances per ISO 2768-m, straightness within 0.1 mm, hardness variation ±2 HRC

Test Method

Dimensional inspection via CMM, hardness testing per ASTM E18, fatigue testing under simulated brake pedal cycles, salt spray testing per ASTM B117 for corrosion resistance

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Pushrod

Manufacturer profiles associated with Pushrod.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the primary function of a pushrod in a brake master cylinder?

The pushrod transmits mechanical force from the brake pedal to the master cylinder piston, initiating hydraulic pressure in the braking system.

How do I know if a pushrod needs replacement?

Signs include excessive brake pedal free play, uneven braking, unusual noises during pedal application, or visible wear/corrosion on the rod surface.

Are pushrods interchangeable between different vehicle models?

No, pushrods are typically model-specific due to variations in length, thread type, and mounting geometry; always use OEM or verified compatible parts.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Pushrod