Brakes
02.2 / Characterization & Potential Improvements
Which brake parts are fitted, what condition they are in, and which changes the evidence supports.
Project methodology / This page: Inspect, Measure, Analyze
- 01 Understand
- 02 Model
- 03 Inspect
- 04 Measure
- 05 Analyze
- 06 Improve
- 07 Test
- 08 Reflect
Existing Condition
What am I starting with?
The first step is to identify what is actually on the car. Its model year gives me a factory reference, but it does not identify parts that may have been changed since then.
I need to record the assemblies present, missing components, visible damage, and any signs of leakage. Those observations will establish the starting point for deciding what can be reused and what needs attention.
Documentation pending
The installed components, inspection findings, and measurements have not yet been recorded on this page. No parts are currently classified here as reusable or rejected.
Architecture Identification
Which brake design and components are fitted?
I will identify the parts from their markings, dimensions, and connections. Matching the general appearance of a factory diagram is only a starting point.
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01
Front assemblies
Record the brake type, caliper markings and configuration, disc dimensions, and mounting arrangement on both sides.
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02
Rear assemblies
Record the drum and backing-plate identification, shoe arrangement, wheel-cylinder markings, and adjuster design if the factory-style drums are fitted.
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03
Master cylinder & circuits
Identify the master cylinder, bore specification, reservoir, and circuit layout. Trace the pipe connections rather than inferring the circuit arrangement from the reservoir alone.
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04
Pipes & hoses
Record routing, supports, flexible hose locations, fittings, and any visible departures from the reference layout.
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05
Parking brake
Identify the hand lever, cables, linkage, and connection to the rear brakes. Record any missing or altered pieces.
Component Screening
What does each assembly need?
These entries define what I need to document. Each finding should identify the component and its location, so a problem on one side does not become an unsupported conclusion about the entire axle.
01 Front discs & pads
Record surface condition, corrosion, scoring, visible cracks, and the wear pattern on each pad. Keep the inner and outer pad findings separate.
Disc thickness and runout need measured values and the correct limits for the identified parts before I can make a reuse decision.
02 Calipers & mounting hardware
Record visible leakage, seal and dust-boot condition, corrosion, mounting condition, and any evidence of uneven operation.
Whether a caliper is suitable for reconditioning depends on its exact design, internal condition, and applicable service information.
03 Rear drums, shoes & cylinders
If drums are fitted, record the friction-surface condition, shoe wear, contamination, wheel-cylinder leakage, and the condition of the springs and adjusters.
Record each drum's internal diameter and compare it with the limit for that drum. A nominal factory diameter is not a wear limit.
04 Master cylinder, pipes & hoses
Record the master-cylinder condition, fluid specification if documented, signs of leakage, pipe corrosion, damaged supports, and visible hose damage or rubbing.
Fluid type and hydraulic condition remain unconfirmed until supported by records and appropriate checks. Appearance alone does not establish either.
05 Pedal & parking-brake mechanism
Record pedal-pivot and linkage condition, movement, and the specified free-play checks for the fitted arrangement.
For the parking brake, record cable condition, linkage movement, and whether the mechanism applies and releases at both rear wheels. Holding performance requires a separate test record.
Measurement Record
Which numbers support the assessment?
Each measurement needs a component location, units, a measurement method, and a source for the applicable specification.
I will keep measured values separate from reference dimensions and assumptions used in the Theory page. None of the example calculation inputs count as measurements of this car.
- Front discs
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Not recorded
Left and right disc thickness, variation between measurement positions, and runout. Include the identified disc's minimum thickness and the applicable runout limit.
- Rear drums
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Not recorded
Left and right internal diameter, variation with measurement position, and the matching maximum-diameter specification if drums are fitted.
- Pads & shoes
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Not recorded
Friction-material identification, remaining thickness, and wear pattern at each wheel. Record contamination or damage alongside the dimensions.
- Hydraulic dimensions
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Not recorded
Master-cylinder bore, caliper type and piston sizes, and rear wheel-cylinder sizes where applicable. Label catalogue specifications separately from physical measurements.
- Vehicle & pedal inputs
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Not recorded
Pedal geometry, actual tire size and effective rolling radius, vehicle mass, and axle loads needed to replace assumptions in the model.
Comparison to Theory
Does the model describe the hardware I have?
The Brake Theory page provides the operating principles. The identified parts and measured dimensions will determine which assumptions apply to this car.
Factory reference: the Triumph workshop manual lists 9-inch front discs and 7-inch rear drums for the early Spitfire, with a mechanically operated rear handbrake. These describe the reference arrangement; they are not confirmed measurements or identifications of my parts. [1]
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01
System layout
Compare the observed front and rear brake types, hydraulic circuits, and parking-brake linkage with the reference arrangement.
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02
Pressure & travel
Use the identified master-cylinder bore and measured pedal geometry to replace the example inputs. The model also needs the actual caliper and wheel-cylinder arrangement.
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03
Brake torque
Use the correct piston areas and effective friction radius for the fitted brakes. Friction coefficients remain assumptions unless supported by data for the pad or shoe material.
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04
Balance & heat
Update the model with the car's mass, axle loads, tire information, and brake dimensions. Calculated results remain predictions until compared with test evidence.
Characterization Limits
What can I conclude from the available evidence?
With the findings still pending, I cannot yet conclude which components are suitable for reuse or whether the existing brake arrangement needs a design change.
Inspection and dimensional checks can identify defects and compare parts with service limits. They do not establish stopping distance, fade resistance, left-to-right braking consistency, or parking-brake holding performance.
Reconditioning feasibility also depends on the exact component design, its internal condition, and the availability of compatible service parts. Those decisions will remain open until the evidence is recorded.
Potential Improvements
Which changes would the findings justify?
These are options to evaluate after characterization. No brake modification or replacement list has been selected on this page.
Address confirmed wear or damage
If inspection identifies leaking hydraulic components, damaged hoses, or friction parts outside their service limits, those findings will support specific service or replacement decisions.
The record should identify the failed check and the specification used. For discs, minimum thickness must be tied to the identified part. [2]
Investigate uneven operation
If inspection or testing shows unequal wear, incomplete release, or a difference between the two sides, I will use those findings to identify the cause and the work needed.
The resulting improvement would be judged by repeat checks and recorded operation after the work.
Evaluate changes against a measured baseline
If baseline testing identifies a limitation in pedal effort, friction behavior, or heat capacity, I can compare possible changes against that specific problem.
Any hardware proposal needs to account for pedal travel, front-to-rear balance, and wheel clearance. A performance claim will need before-and-after evidence.