Skip to content
Mendocino, California. Delivery all over Northern California. Call or text (909) 259-7837

Free RV manual

How Trailer Brakes Work

Electric brakes, the brake controller in your truck, how to set the gain and how to test the breakaway switch.

How they work

Most travel trailers and fifth wheels have electric drum brakes. When you step on the brake in the truck, a brake controller sends power down the 7 pin cord to magnets in each drum. The magnets pull the brake shoes against the drum.

If the trailer has brakes, the truck needs a brake controller. Most states require brakes on trailers over a set weight.

Setting the gain

  1. Hook up and load the trailer the way you will travel.
  2. On a dry, empty road, drive at about 20 to 25 miles per hour.
  3. Squeeze the manual lever on the controller all the way.
  4. The trailer brakes should grab firmly without locking the wheels. If the wheels lock, turn the gain down. If it barely slows, turn it up.
  5. Set it again when the load changes a lot.

The breakaway switch

A small box on the tongue has a pin on a cable clipped to the truck. If the trailer ever comes loose, the cable pulls the pin and a battery on the trailer locks the brakes.

Test it before a trip. Pull the pin and try to pull forward slowly. The trailer should drag. Push the pin back in right away, since it drains the battery fast.

Clip the cable to the truck frame, not to the hitch or the safety chains. It has to pull the pin if the whole hitch lets go.

Care

Electric brakes need adjusting as the shoes wear. Most need a check once a year when the bearings are serviced. A brake that pulls, grinds or does nothing on one wheel needs a look.

When to call a shop

Call a shop if the controller shows no connection, the brakes lock at low gain, one wheel drags hot, or the breakaway will not lock the brakes.

The maker's own manuals

These guides cover how most RVs work. Your own rig may differ, so check the manual for your make and model.

Renting from us? Call or text 909-259-RVDR before you try a fix. We would rather talk you through it than have you guess, and it is free.

The other manuals

ManualFresh water and the water heaterCity water, the fresh tank, the pump and the water heater. How to fill it, turn it on and keep it clean.5 partsManualBlack and gray tanksThe order, the hose, the valves and what to put down the toilet. Dumping your tanks the right way, step by step.4 partsManualShore power and batteries30 amp and 50 amp shore power, the 12 volt battery side and the inverter. What runs on what, and how not to trip a breaker.4 partsManualPropane, furnace and fridgeOpening the tanks, lighting the stove, running the furnace and fridge, and what to do if you smell gas.5 partsManualSlide outsWhen to open them, when not to, and what to check first. Slide outs are the most common repair on a rental, and most of it is avoidable.4 partsManualAwningsPower and manual awnings, how to set them, and why wind is the thing that breaks them.4 partsManualWinterizing and spring start upDrain it, bypass the water heater and fill the lines with RV antifreeze. Then how to undo it all in spring.4 partsManualGeneratorsStarting it, loading it, keeping it healthy, and staying safe from exhaust.4 partsManualHitching a trailerCoupler, safety chains, breakaway cable and lights. A simple routine to hitch up the same way every time.4 partsManualThe water heaterGas, electric or both. How to fill it, light it, drain it and care for the anode rod, plus what to do when there is no hot water.4 partsManualThe refrigeratorGas and electric absorption fridges, 12 volt compressor fridges, how long they take to cool and how to keep food cold on the road.4 partsManualThe roof air conditionerHow much power it needs, why it freezes up, how to clean the filters and what to try before you call for help.4 partsManualThe furnaceA propane furnace with a 12 volt fan. How it starts, why it drains the battery and what to check when it blows cold air.4 partsManualLeveling and jacksBlocks, tongue jacks, stabilizers and auto leveling. How to get level, why it matters and why stabilizers are not for lifting.4 partsManualTires, wheels and bearingsTire age, pressure and load, lug nut torque and when to service trailer wheel bearings. The parts that cause the most trouble on the road.4 partsManualRoof and sealsWater is the biggest enemy of an RV. How to check the roof and seams, which sealant to use and the signs of a leak.4 partsManualThe toiletHow to flush, what paper to use and how to keep the black tank from clogging or smelling.4 partsManualPropane, smoke and CO alarmsWhere each alarm is, what each one means, how to test them and why the propane alarm sometimes beeps on a low battery.4 partsManualSolar and lithium batteriesHow solar charges your batteries, what lithium changes, and how to tell how much power you really have left.4 partsManualTowing a car behind a motorhomeWhich cars can be towed four down, the gear you need, and the steps before and after every tow.4 partsManualWeight and payloadWhat GVWR, cargo capacity and tongue weight mean, how to weigh your rig, and why sway almost always starts with weight.4 parts
Call us Text us