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LoginDisc Brake Validation Testing System
Pneumatic and electronic dual-tappet force measurement — the diagnostic standard behind every Fraser Gauge remanufactured caliper.
Every caliper that leaves our facility has been tested on this system. The Final Inspection Report that ships with your order is not a formality — it is a data record of exactly how your caliper performed before it was packed.
See the System in Action
Two perspectives on the Fraser Gauge Disc Brake Validation Tester: a live bench test and a clean-environment demonstration of the full testing workflow.
Live Bench Test — EX225 Caliper Validation
Testing Environment Overview — Clean Lab Demonstration
Dual-Tappet Force Curve — Interactive Simulation
This simulation replicates the force curve analysis performed on every remanufactured caliper. Both tappet channels must exceed 2,800 lbs and track in synchronization throughout the full apply-hold-release cycle.
Dual-Tappet Force Analysis
Live simulation of the Fraser Gauge pneumatic caliper validation cycle
System Components
The Fraser Gauge Disc Brake Testing System is a three-component assembly: the Base Testing Unit, the platform-specific bench spacer, and the load cell set for the target caliper model.
Base Testing Unit
The control console houses the pneumatic and electronic control system. The LED faceplate displays Time Set, Cycle Time, and live PSI pressure via an analog gauge. Controls include Set Time and Set PSI sliders, Auto Time / Auto PSI modes, Cycle Start, Reset, Reboot, and Shutdown. Recommended cycle time: 5–10 seconds.
LED Control Faceplate
The faceplate provides the operator interface: dual LED displays for Time Set and Cycle Time, two vertical sliders for Set Time and Set PSI, a RELEASE/APPLY toggle pair, and a precision PSI pressure gauge calibrated to 60 PSI. Color-coded control buttons (yellow RESET, cream REBOOT, red SHUTDOWN) ensure unambiguous operation in a shop environment.
Diagnostic Capabilities
The system measures six independent parameters simultaneously. Each parameter maps to a specific failure mode — giving the technician a precise diagnosis, not a guess.
Tappet Force Output
Measures the individual output force of each tappet to verify synchronized actuation pressure.
Application Timing
Records the exact time each tappet takes to apply from rest to full pressure — identifies sluggish or seized components.
Release Timing
Measures time to full release — detects worn guide pins, seized bushings, or air chamber dysfunction.
Tappet Synchronization
Compares left and right tappet curves in real time — both must actuate and release in unison at equal pressure.
Pressure Hold Integrity
Monitors pressure stability during the hold phase — detects internal leaks or adjuster mechanism drift.
Final Inspection Report
Every remanufactured caliper ships with a printed report: Function Test, Pressure Test, Torque Inspection, Seal Inspection, and Adjustment Test.
The Testing Process — Step by Step
Every Fraser Gauge remanufactured caliper follows this seven-step validation protocol before it is cleared for shipment.
Mount Pressure Transducer
The pressure transducer is mounted to the backing plate of the disc brake pad. Each caliper model uses the pad designed for that specific platform — Meritor EX225, Knorr SN7/SB7, and others each have a dedicated transducer pad.
Install Bench Spacer
The bench testing spacer is positioned to simulate the rotor gap, allowing the caliper to be tested off-vehicle on the bench. The spacer is platform-specific and ensures the tappets travel the correct stroke distance.
Connect Load Cells
EX225 load cells (or the appropriate platform cells) are installed to capture the force output of each tappet independently. Electrical connections from the transducers route to the Base Testing Unit.
Set Test Parameters
The technician sets the cycle duration (recommended: 5–10 seconds) and target PSI using the Set Time and Set PSI sliders. Auto Time and Auto PSI modes are available for standardized production testing.
Run Test Cycle
Pressing Cycle Start applies pneumatic pressure through the system. The unit records force output, application time, and release time for each tappet simultaneously. Multiple cycles can be run to confirm repeatability.
Analyze Software Output
The software plots left tappet (yellow line) and right tappet (red line) force curves against sample time. Both curves must overlap — identical pressure, identical timing. Any divergence indicates a specific failure mode: seized pin, worn bushing, adjuster drift, or air chamber imbalance.
Issue Final Inspection Report
A printed Final Inspection Report is generated and shipped with every remanufactured caliper. It documents: Function Test pass/fail, Pressure Test result (150 PSI pneumatic), Torque Inspection, Seal Inspection, and Adjustment Test.
Software Analysis — Reading the Output
The tester plots left tappet (yellow) and right tappet (red) force curves against sample time in seconds. The following scenarios represent the four primary diagnostic outcomes.
Left Axis: Actuation Pressure (PSI) | Bottom Axis: Sample Time (seconds) | Yellow Line: Left Tappet | Red Line: Right Tappet
Final Inspection Report — Included with Every Caliper
Every remanufactured caliper shipped by Fraser Gauge includes a printed Final Inspection Report documenting the results of the complete validation protocol. This report is your quality record — it confirms that the specific unit in your hands was tested, not just that the model was tested.
On-Vehicle and Bench Testing
The Fraser Gauge Portable Disc Brake Testing Fixture is designed for both bench and on-vehicle diagnostics. Fleet maintenance teams can use the same system to test installed calipers without removing them from the vehicle — identifying air chamber imbalances, guide pin seizure, and adjuster drift in the field.
Bench Testing
- Full tappet force and timing analysis
- Platform-specific bench spacer simulates rotor gap
- Load cells capture independent tappet force curves
- Used for 100% final inspection of all remanufactured units
On-Vehicle Testing
- Diagnose installed calipers without removal
- Compare air chamber function side-to-side on same axle
- Identify worn guide pins and seized bushings in service
- Portable design — usable in the maintenance bay
netBrake Decelerometer
The netBrake is a rugged IP68 tablet-based mobile brake testing system for road-going commercial vehicles. Real-time deceleration graphs, Bluetooth printing, FMVSS 121 compliant, and MOT approved.
Ideal for fleet managers, transit authorities, workshop owners, and accident investigators who need certified, on-site brake performance documentation.
