RV Guy Mobile RV Service

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Stop It!  By: Ed Tworek Certified RV Technician


Stopping.  Probably the most important thing an RV must do!  Braking systems in RV’s come in three flavors, Electric, Hydraulic and Air.  Air brakes are typically found on large motorhomes that are built on truck or bus chassis.  Hydraulic brake systems are the type we are most familiar with, these systems are found on everything from motorcycles to small trucks.  Electric brake systems are reserved for trailer use.  

In this article we are going to discuss maintenance that you, the consumer to can on your brake systems.  To that end, we are going to eliminate air brake systems from this discussion.  Air brakes are dangerous!  Unless you are trained to work on air brake systems, leave any repair or maintenance to a professional. 

Hydraulic braking systems use fluid to apply pressure  to the brake shoes or pads.  When you step on the brake pedal, you are forcing the hydraulic fluid to build pressure which then forces the pads or shoes to move, grabbing the brake drum or caliper, slowing the vehicle down.  If you are even the slightest mechanically inclined and have a few basic tools, you can easily check the condition of your pads or shoes.  The level of hydraulic fluid in the reservoir should be checked at least every six months.  Certainly, you MUST check it prior to a road trip.  Add the correct fluid to the full mark on the reservoir.  Use a flashlight to follow the tubing from the reservoir looking for signs of leakage. 

To check the shoes or pads, you need to remove the tire.  Gather up the tools you will need; a jack capable of lifting your rig, jack stands, wheel chocks, lug wrench.  And if your unit has drum brakes, you will need to remove the drum.  To do this you will need needle nose pliers, and a large set of adjustable pliers.  Shop rags and gloves are also recommended. 

Set your jack at the manufacturer’s recommended lifting location.  Set the parking brake or chock the wheels.  Lug nuts can be attached very tightly.  Loosen the lug nuts while the weight of the unit is still on the ground.  Once loose, jack the unit up.  Raise it up just enough so you can remove the tire. Place the jack stand under the trailer frame or axle.  Remove the lug nuts and pull the tire.

If you have disc brakes, all you need to do now is check the condition of the rotor and the pads.  Feel the rotor, looking for deformities, gouges and damage.  Look at the pads for thickness.  If all looks good, put the tire back on, lug nuts as tight as you can while it is in the air and then lower the unit to the ground.  Now, using a torque wrench, tighten the nuts to the specified torque for your vehicle.  Do this for each wheel.

If you have drum brakes, the job gets messy.  Follow the above steps to remove the tire.  Now you will have to remove the drum.  The drum is held in place with a large nut.  The nut has either a cotter pin or a retainer.  Remove the retainer or cotter pin, and remove the nut with your pliers.  It is convenient to have a shop rag just below your work to place the greasy parts on.  There is also a large washer that is behind the nut.  Now grab the drum and pull it off. 

You are now checking the drum and pad condition.  The drum should be fairly smooth.  Look at the pads.  They should be wearing evenly and have a minimum of 3/16” thick.  Now is a good time to shoot some brake cleaner on all of the brake parts.  If you have electric brakes- Check the condition of the magnet.  It will be worn on a slight angle.  It should be attached to the backing plate.  Check the wiring to the brake.  Now just reassemble the drum.  Put the drum on the spindle, the washer and nut.  Tighten the nut till snug and then back it off just enough to allow the cotter pin or retainer to line up.  Insert the cotter pin or install the retainer.  Then follow the steps above to install the tire. 

On electric brake systems, a good way to check the efficiency of the brakes, is to apply power to the system while the wheel is in the air.  Activate the emergency break away switch, this will send power to the brake system.  Now turn the wheel to see if the magnet has activated, applying the brakes. 

Remove your jack stand, and set the unit on the ground slowly.  Don’t forget to de-activate the break away switch!