How to Properly Burnish Your Trailer Brakes

If you've got electric drum brakes on your trailer — whether it's a brand new rig or one you just put fresh brakes on — you need to go through a burnishing procedure before you start hauling loads. This isn't optional, and it's not something manufacturers include just to cover themselves. It's a real process that makes a real difference in how your brakes perform.

I'm going to walk you through it step by step. Both methods — the standard approach most owners can do themselves, and the faster highway method I use when doing this as part of a service call. Read through the whole thing before you go out and do it. Understanding why each step matters helps you do it right.

Note: This guide covers electric drum brakes only. If your trailer has electric-over-hydraulic disc brakes, you don't need to burnish them.

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Step 1 — Understand What You're Doing

When brake shoes, magnets, or drums come out of the box, the friction surfaces are machined flat — but they're not perfectly matched to each other yet. The shoe lining needs heat and repeated pressure to fully cure and conform to the curve of the drum. The electromagnet needs the same treatment so it swings in and makes full contact when it's supposed to.

What you're doing during burnishing is generating controlled heat through repeated brake applications. That heat cures the shoe lining material and seats everything together. Once it's done, you should be close to 100% contact between the shoe and the drum — and you'll feel it. Brakes that have been properly broken in feel noticeably stronger and more consistent than ones that haven't.

Skip this step and you're leaving braking performance on the table from day one. In some situations that's just annoying. In others, it's a safety issue.

When does this apply? Any time the friction surfaces are new or have been replaced — new trailer, new brake shoes, new magnets, new drums, or a full axle swap. If you're not sure whether the last owner ever did this on a used trailer, go ahead and run through it anyway. It won't hurt anything.

Step 2 — Get Set Up

Before you go anywhere, make sure everything is properly connected and functioning. A loose electrical connection means no signal to the brakes. Run through this checklist before you roll:

• Ball head seated, locked, and safety chains crossed and connected
• Breakaway cable hooked to tow vehicle — separate from safety chains
• All electrical connections plugged in and secure
• Running lights, brake lights, and turn signals all working
• Brake controller powered on and reading the trailer
• Weight distribution hitch and sway control set if applicable
• Tires inflated to spec on both tow vehicle and trailer

Now find yourself a good stretch of road. You want light traffic, a straight path, and at least a mile or two of clear road ahead of you. A lightly traveled state highway or a rural road with good sight lines works well. You don't want traffic stacking up behind you while you're doing repeated brake applications.

Step 3 — Set Your Brake Controller

This is the step people skip, and it's the reason their burnishing doesn't work. You need to turn the gain on your brake controller all the way up to maximum before you start. The gain controls how much voltage gets sent to the trailer brakes. During the burnishing procedure, you want full voltage — 8 to 10 volts — hitting those brakes every time you apply them. That's what generates the heat needed to cure the shoe lining.

If you run normal towing gain during the burnish, you'll get some heat but not enough. The drums will get warm but you won't achieve the full cure. You'll think you did the process and still end up with underperforming brakes.

After the burnish is complete, dial the gain back to your normal towing setting. You don't want to tow with maximum gain — the brakes will be too aggressive for normal stops.

Step 4 — Run the Burnishing Procedure

There are two methods. Pick the one that fits your situation. Both get the job done.

Method A — Standard Procedure

Best for most owners. Lower speeds, more passes. Works great on a rural road or lightly traveled highway.

1. With gain maxed out, get the truck and trailer up to 40 mph.
2. Use the manual override slide on your brake controller — not your tow vehicle brakes — to apply the trailer brakes. Target 8 to 10 volts to the brakes. Let them slow you down from 40 mph to about 20–25 mph.
3. Do not touch the tow vehicle brakes or exhaust brakes while the trailer brakes are applied. You want all the heat going into the trailer brake system, not split between both vehicles. This is the key to seating the shoes fast.
4. Release the slide. Get back up to 40 mph.
5. Repeat every mile or so. Plan on 20 to 50 passes. You'll often feel the brakes grabbing harder well before 50 — that's the lining curing and conforming to the drum. Trust what you feel, but don't stop before 20.
6. After 20+ applications, pull over somewhere safe and check your work (see Step 5).

Method B — Technician Procedure

Faster and more aggressive. Requires highway speeds. Good for experienced towers or when done as part of a professional service.

1. Gain maxed out. Get up to highway speed — 60 to 70 mph. Stay at or below the posted speed limit.
2. Use the manual slide on the brake controller to apply the trailer brakes. Maintain your highway speed while the brakes are dragging — don't let the rig slow down. Don't lock the brakes up either. Steady drag at speed is what you want.
3. Hold that for a half mile with consistent brake pressure and constant speed.
4. Release the slide. Pull over safely and check the brakes (see Step 5).

Which method should you use? Method A takes longer but is straightforward and forgiving. Method B generates more heat faster and typically seats the brakes in one pass, but you need to be comfortable maintaining highway speed with the brakes dragging. If that sounds like a lot to manage, stick with Method A — same result, just more passes.

Step 5 — Check Your Work

After you pull over, walk to the axles and check the brake drums. Here's what each result means:

Smoke coming off the brake or axle area

This is normal during burnishing. It means the friction surfaces are heating up correctly. Don't panic — let it smoke and keep going.

Drum is very hot — hand can't get close without feeling strong radiant heat

You're in the right temperature range. Target is 350–400°F at the drum surface. If you have an infrared temp gun, use it. If not, the hand hover test works fine — get close without touching, and if the heat pushes your hand back, you're good.

No smoke and drum is warm but touchable

Not enough heat was generated. The brakes haven't reached curing temperature. Run through the procedure again with more passes.

Drum is cold to the touch after multiple passes

The brakes aren't doing any work at all. This points to one of two problems: the brakes are out of adjustment and the shoes aren't contacting the drum, or there's a wiring issue and the magnets aren't getting power. Stop and troubleshoot before continuing — this isn't a burnishing problem, something else is wrong. Give me a call.

Never touch the brake drum directly during or right after the procedure. It can exceed 400°F. Always hover your hand — never make contact.

Step 6 — Wrap Up and Get Back on the Road

Once the drums are coming up to temperature and the brakes are grabbing consistently and firmly, you're done.

1. Let everything cool down before you load up and head out. You just put serious heat into those brakes — give them time to come back to ambient temperature before putting them back to work.
2. Dial your brake controller gain back to your normal towing setting.
3. Do a quick function check — slow roll and apply the trailer brakes manually to confirm they're engaging evenly and the rig stops straight.
4. You're done. Go haul something.

Quick Reference Checklist

• Confirm you have electric drum brakes (not disc)
• Check all connections — hitch, electrical, breakaway cable
• Set brake controller gain to maximum
• Method A: 40 mph → apply trailer brakes to 20–25 mph → repeat 20–50 times
• Method B: 60–70 mph → drag brakes at speed for half a mile
• Pull over and check for heat and smoke at the drum
• Repeat if drum isn't hot enough
• If drum is cold, diagnose wiring or brake adjustment before continuing
• Let brakes cool, reset gain to normal, do a function check

Need axle parts for your trailer?

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Need Brake Service?

I do mobile brake service throughout Northern California — new shoes, magnets, drum replacements, full adjustments, and burnishing as part of the job. If you'd rather not do this yourself, or want someone to verify everything is set up correctly first, give me a call.

Jesse Allred — Allred Trailer Service

allredtrailerservice.com

jesse@allredtrailerservice.com

If you'd rather have a professional handle your trailer brakes, Allred Trailer Service provides expert [trailer brake repair](/#services) in the Sacramento area. We do the full burnishing procedure as part of every brake service call.

Frequently Asked Questions

How many stops do I need to make to burnish trailer brakes?

Plan on 20 to 50 brake applications using Method A (40 mph down to 20–25 mph). You'll often feel the brakes getting firmer well before 50 passes as the lining cures into the drum. Don't stop before 20 passes — heat is what seats the friction material.

Do new trailer brakes need to be burnished?

Yes. Any time friction surfaces are new — new trailer, new shoes, new magnets, new drums, or a full axle swap — you need to burnish them before hauling loads. Skip this and you leave significant braking performance on the table from day one. In some situations that's just annoying. In others, it's a safety issue.

What does a properly burnished drum feel like?

The drum should be hot — target 350–400°F at the surface. You may see smoke coming off the brake area during the procedure, which is normal. After cooling, brakes that have been properly burnished feel noticeably firmer and more consistent than before the procedure.

Can I burnish trailer brakes without a brake controller?

No. You need a functioning brake controller to apply the trailer brakes independently of the truck brakes. The controller gain must be set to maximum before starting — this delivers 8–12 volts to the magnets and generates the heat needed to cure the friction material.

How do I know if my trailer brakes were never burnished?

Underperforming brakes that feel weak even after proper adjustment are the most common sign. If the drum stays cold after 20+ passes, the brakes are either out of adjustment and the shoes aren't contacting the drum, or there's a wiring problem preventing the magnets from getting power — both require troubleshooting before continuing.