DIY Network

RV Maintenance: Brake Service and Electric Tongue-Jack From "Weekend Mechanic" episode WKM-309

	Bruce Bonebrake installs a new electric-brake assembly on an RV to get it road-ready.
	Figure A

Traveling in an RV can be lots of fun, but to make RV travels trouble-free it's important to keep an RV in good condition. A campground in a remote location is nowhere to discover that you need repairs. In this episode, Weekend Mechanic host Bruce Bonebrake demonstrates some important maintenance procedures that should be performed to get a trailer RV ready for a trip. The aging electronic brakes are replaced and the wheel bearing repacked. An electric tongue jack is added. The gas, water and electrical systems are checked to make sure they are working right. A leaky roof vent is replaced with a new vent and vent cover. To top it all off, a new RV satellite-dish is installed on the roof and checked for reception. Assisting Bruce in this episode is automotive specialist Bobby Ray Adams.

In this first segment, work begins with the brakes, bearings and wheels. We remove the electric brakes from the wheels of the trailer. Then the wheel bearings are repacked with grease. The entire brake assembly is replaced with a new brake assembly and the wheels are reinstalled. An electric tongue jack is installed then on the front of the trailer.

To begin work on the wheel bearings and brakes, we first jack the RV and support it using jack stands (figure A).

Important: Before jacking up the trailer, make certain that it is attached to the tow vehicle, and that the parking brake is set. And to avoid potential damage to the axle, support the trailer underneath the frame, not the axle.

Safety Alert: As a standard safety precaution, don't rely solely on a jack to support the weight of a vehicle. When using a jack to access or work beneath a vehicle, always use jack stands for support.

DIY Difficulty Rating for the Project: The procedures shown in this episode are all fairly routine or straightforward. Overall, we gave these projects a difficulty rating of 2 on a 5-point intermediate-level scale. It took us about 8 hours to finish this job. Depending on your vehicle and it's condition, and the nature of any problems you might encounter, your work time could vary. Allow yourself a full weekend to complete these projects properly.

Materials:

In addition to standard auto-mechanic's tools (wrenches, ratchets, extenders, screwdrivers, nut-drivers, etc.), some of the specialty tools used in this episode include test light, torque wrench, caulking gun, wire cutters and wire strippers, heat gun, oversized socket attachment, bearing packer, cleaning brush, degreaser and latex gloves. An air-compressor and set of pneumatic tools will is optional, but may be very helpful for this project.

advertisement

Electric-Brakes Servicing

• With the trailer properly supported on the jack and jack stands, use pliers to remove the plastic caps covering the lug nuts, then remove the lug nuts. We removed ours using an air-powered wrench and air-impact socket (figure B).

• With the tires removed, it's a good time to inspect them for wear and deterioration. In addition to checking the wear on the treads, check the sidewalls and areas between the treads for cracking or rot. Also check the condition of your spare tire.

• With the tires removed, loosen and remove the grease cap that protects the axle castel-nut. Bend back and remove the cotter pin that holds the nut in place, and carefully remove the nut (figure C). Carefully lift off and the bake drum and bearing. As part of this servicing, the bearings will need to be inspected and repacked.

  Figure B

  Figure C

  
  

• Inspect the electric brakes on the trailer. For these brakes to operate properly, the electric coil should be positioned with the magnet at the front of the assembly (figure D).

• Our inspection revealed a broken spring on the rear brake shoe (figure E). Based on the overall condition of our brakes, we opted to replace the entire brake assembly.

  Figure D

  Figure E

  
  

  	Figure F
  	Figure G
  	Figure H

• Here are the basic procedures for repacking the wheel bearings:
  1. First pull out the rear-bearing retaining ring and remove the rear bearing for cleaning.
     
  2. Clean the bearing thoroughly using a strong solvent or degreaser to remove dirt, metal particles and old grease.
     
  3. Towel-dry the bearing to absorb any solvent.
     
  4. Once it is dry, place the bearing into a bearing packer. Fill the packer with grease.
     
  5. The bearing is forceed into the packer using a sleeve pushes the bearing into the grease evenly, coating all of the bearing-rollers at the same time.
     
  6. Once the bearing has been repacked with grease (figure F), it can be reinserted into the wheel hub (figure G).
     
  7. With the bearing back in position, carefully tap the retaining ring back into place.
     
  8. On the other side of the wheel, grease the inside of the bearing collar well so that the outer bearing can be easily installed when the wheel goes back on the axle(figure H).
  
  

  Figure I

• The brake assembly, including the backing assembly, can be removed as a single unit. To remove the old brake assembly, loosen and remove the four retaining nuts that hold it in place.

  Note: The backing-plate bolts are likely rusty. Spraying them first with penetrating oil may make it easier to remove them.

• With the nuts removed, carefully lift off the entire brake assembly (figure I). You'll need to cut the wires that connect the electronic brakes to the wiring harness.
  

• You can now install the new brake assembly. The magnet has two wires attached (figure J). These are connected to the wiring harness like the old ones were. It shouldn't matter which wire attaches to which connector on the harness since the wiring is connected to an internal coil.

• To connect the wire on the assembly to the trailer harness, strip the ends of the new wires using a wire stripper, and make the connection using a plastic crimp-connector. Repeat for the second wire. Use a heat gun to heat the connections and weatherproof the connections (figure K)

  Figure J

  Figure K

  
  

• Position the new brake assembly (figure L) taking care to first position the wiring harness so that the wires will not be pinched or damaged when the new assembly is secured in position on the mounting bracket on the axle.

• Once the new assembly is in position, secure it with the retaining bolts and nuts.

• Apply grease to the axle (figure M) and carefully install the brake drum on the axle, taking care to avoid damaging the axle-nut threads.

  Figure L

  Figure M

  
  

  	Figure N
  	Figure O

• With the brake drum back in place, position the outer bearing and grease seal onto the axle (figure N).

• Place the slotted washer over the bearing (figure O).

• Place the castel nut on the axle and hand-tighten it.

• Use a torque wrench to tighten the castel nut to the proper torque specs (in our case, it was 50 foot-pounds).

• Replace the grease cap.

• Reinstall the wheels and tires.

• Adjust the brake-adjustment screw until the shoes do not touch the drum.

• Repeat this process on the remaining wheels to complete the electric-brake service.
  

All travel trailers have some type of tongue jack to crank the trailer up and down for attaching to the tow vehicle, and also for leveling the trailer. Commonly this is simply a manual jack that must be hand-cranked (figure P). We upgraded our RV by replacing the manual jack with a electric one. Here are the steps for this simple upgrade.

Remove the three bolts that hold the old tongue-jack in place (figure Q), and carefully lift the old jack out of the tongue.

Figure P

Figure Q

	Figure R
	Figure S