Float Arm: Load Capacity 5-20N, Length 80-250mm

Component Specifications

Definition

The float arm is a precision mechanical component in automotive fuel level sensors that converts the vertical displacement of a buoyant float into rotational movement. This movement is transmitted to a variable resistor or Hall effect sensor to generate electrical signals proportional to fuel volume. It operates within the fuel tank environment and must maintain accuracy across temperature variations, vehicle motion, and fuel slosh conditions.

Working Principle

Buoyancy principle: The float rises/falls with fuel level, causing the attached arm to pivot. This rotational movement changes resistance in a potentiometer or alters magnetic field position for Hall effect sensors, creating voltage signals corresponding to fuel volume.

Materials

Stainless steel (AISI 304/316) for corrosion resistance, aluminum alloys (6061-T6) for lightweight applications, or engineered plastics (POM, PEEK) with fuel compatibility. Hinge pins typically use brass or stainless steel.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Length	80-250mm
Accuracy	±2-5% of full scale
Load Capacity	5-20N
Rotation Angle	0-90 degrees
Fuel Compatibility	Gasoline, Diesel, Ethanol blends
Operating Temperature	-40°C to +125°C

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 2575, DIN 72785, SAE J1930

Parent Products

This component is used in the following industrial products

Fuel Level Sensor

A sensor that measures and monitors the amount of fuel remaining in a fuel tank.

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Engineering Analysis

Risks & Mitigation

Fuel leakage if seals fail
Inaccurate readings from stuck/worn components
Electrical shorts in wet environments
Material incompatibility with alternative fuels

FMEA Triads

Trigger: Hinge corrosion/wear
Failure: Sticking or binding movement
Mitigation: Use corrosion-resistant materials, regular maintenance checks, protective coatings

Trigger: Float saturation/leakage
Failure: Buoyancy loss causing reading errors
Mitigation: Sealed float designs, material testing for fuel compatibility, moisture barriers

Trigger: Electrical contact degradation
Failure: Erratic or no signal output
Mitigation: Gold-plated contacts, sealed connectors, redundant contact designs

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.5mm dimensional tolerance, ±1° angular alignment

Test Method

Buoyancy testing in simulated fuels, cycle testing (50,000+ cycles), temperature cycling (-40°C to +125°C), vibration testing per automotive standards

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

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

Manufacturers of Float Arm

Manufacturer profiles associated with Float Arm.

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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 causes float arm failure in fuel sensors?

Common failures include hinge wear from continuous movement, material degradation from fuel additives, float saturation altering buoyancy, and electrical contact corrosion in potentiometer-based designs.

How does temperature affect float arm accuracy?

Temperature changes alter fuel density (affecting buoyancy) and cause material expansion/contraction. Modern designs compensate through material selection and calibration curves.

Are float arms interchangeable between vehicle models?

Not universally. Differences in tank geometry, mounting points, electrical interfaces, and fuel types require model-specific designs, though some aftermarket manufacturers offer compatible versions.

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.

Float Arm