Standard Burnishing Procedure
- Perform the 20–50 brake application sequence to seat brake shoes to the drum.
- Monitor brake drum surface temperatures using an infrared temperature gun to verify friction material activation.
- Verify proper trailer brake controller settings and voltage delivery during the burnishing procedure.
- Infrared temperature gun — Measure brake drum heat to target the 350–400 °F range after the application sequence.
- Trailer brake controller — Apply 8–10 volts manually via the slide to engage trailer brakes independently of the tow vehicle.
- Tow vehicle — Accelerate the trailer to the minimum required 40 mph for the burnishing procedure.
- Safety equipment — Connect the breakaway cable and check the hitch, electrical, and sway bars before starting the drive.
Minimum 40 mph is required. Do not use tow vehicle or exhaust brakes during the procedure.
How It Works
Burnishing Requirements
Minimum speeds of 40 mph are required to generate sufficient kinetic energy for the break-in process. The procedure involves 20–50 applications, slowing the vehicle from 40 mph down to 20–25 mph using only the trailer brake controller slide.
Thermal Management
The friction process generates significant heat and smoke. A target temperature of 350–400 °F indicates successful burnishing. Operators should hover a hand to sense heat but must never touch the drum directly due to burn risks.
Voltage and Interval Control
To prevent glazing or uneven wear, applications must be performed at one-mile intervals using 8–10 volts. The tow vehicle brakes and exhaust brakes must remain disengaged to ensure the trailer brakes perform all deceleration work.
Step-by-Step Procedure
0/9 doneDiagnostic Chart
| Symptom | Check | Spec / Expected | Likely cause & fix |
|---|---|---|---|
| Brake drum is cold or touchable after 20–50 applications. | Inspect brake shoe adjustment and wiring integrity. | 350–400 °F | Mechanical maladjustment or electrical failure prevents the shoes from contacting the drum with sufficient force. Basis: Lippert TI-086 Electric Drum Brake Break-In Period (Rev 08.13.2019) |
| Insufficient heat generation during the procedure. | Verify the brake controller GAIN is set to maximum and 8–10 volts are being applied. | 8–10 volts | Low voltage application prevents the magnets from engaging the shoes forcefully enough to generate friction heat. Basis: Lippert TI-086 Electric Drum Brake Break-In Period (Rev 08.13.2019) |
| Brakes failing to reach target temperature despite repeated applications. | Confirm speed is at least 40 mph before applying the controller slide. | Minimum 40 mph | Speeds below 40 mph do not provide enough energy to reach the required 350–400 °F range. Basis: Lippert TI-086 Electric Drum Brake Break-In Period (Rev 08.13.2019) |
At the Bay: Diagnose the Case
CASE 1 / 3
Brake drum is cold or touchable after 20–50 applications.
- Test
- Compare
- Correct
Select the next check
Basis: Lippert TI-086 Electric Drum Brake Break-In Period (Rev 08.13.2019). A likely cause is a hypothesis; confirm it with the applicable service procedure before repair.
Common Bay Mistakes
- ✕ Using tow vehicle brakes or exhaust brakes during the procedure.
- ✕ Touching the brake drum with bare hands to check for heat.
- ✕ Performing applications at intervals shorter than one mile.
- ✕ Attempting the procedure at speeds below 40 mph.
- ✕ Failing to set the controller GAIN to maximum before starting.
- ✕ Ignoring smoke, which is an expected part of the break-in process.
Quick Check
Practice only — not scored.
Plan the Service Sequence
Planning practice only. Follow the applicable manufacturer's instructions, employer safety program and qualified supervision on real equipment.
Plan the first action. Compare the service steps with the bay mistakes.
Hands-on: Test Bench Practice
Symptom: Healthy trailer. Learn what good readings look like.
Tap a point to place the red probe.
Good system: ~12.6 V at pins, 3.2 Ω across a 12×2-inch magnet (unplugged), 3.0 A per magnet at 12 V full gain, and at least 10.5 V at the magnet — the chart values from the axle manuals.
Hands-on: Shop Test Equipment
IPA #9107B Electric Brake Force Meter
Plugs into the truck's 7-way socket on a 25 ft cable; simulates a trailer load and shows controller output on 10 blue LEDs
🛠 Equip your bay for this test →Symptom: Customer wants the truck checked before buying a trailer.
Spec limits used
- 1–10, each 1.0–1.5 V — Gain LEDs (IPA #9107B manual, p.5)
- 15 s — Max time holding brake pedal (IPA #9107B manual, p.4)
- set-up step 5 — Connect the 9-pin only after the engine is running (IPA #9107B manual, p.3)
- hold brake pedal during ECU detection — 2016–2017 'Trailer Connected' not shown (IPA #9107B manual, p.3)
- faulty brake control module or relay — ECU light never lights on a vehicle with a controller (IPA #9107B manual, p.5)
Simulated readings for practice. Always follow the manufacturer's procedure and values on a real trailer.
Source: Lippert TI-086 Electric Drum Brake Break-In Period (Rev 08.13.2019) — 1–2