Since 2008, Highliner trailers have been built with a stainless steel sleeve installed under the seal.
When “Bearing Buddies” are in use, they produce a small amount of pressure on the grease in the wheel hub, in an attempt to keep water from entering through the grease seal. They are filled at the factory, but need to be greased again after the first trips, or whenever the piston is in the “in” position. If you are constantly greasing the “Bearing Buddy,” you may be greasing only the inside of the rims on a non-brake trailer or on your trailer brakes.
Once the hub is filled, there is no place for the grease to go unless the seal is damaged, in which case you are just filling your brakes with grease, so stop greasing and inspect the brakes!
With oil-bath hubs, the clear plastic cap allows you to see a visual confirmation that there is lubrication to your wheel bearings.
- On the application of brakes, rust particles are forced through the small orifice at the fluid outlet of the master cylinder, and can restrict the fluid flow. When the brakes are released, the springs in the wheels are unable to push the fluid back into the master cylinder, therefore the brakes “Drag”.
- The piston in the wheel cylinders seize up. This commonly occurs when a trailer is backed into a storage location and left for some length of time. When you attempt to move the trailer you will find the wheels locked. The piston is seized in the wheel cylinders , and the brake shoes are expanded against the hub/drums.
Alternatively, the brakes will apply on your first stop and will not release resulting in the brakes dragging.
Winch and Jack
Also, if you walk past the trailer in its’ storage location, I would encourage you to give the handle a couple of turns. And, with the wheel of the jack fully extended put some grease on the inner shaft. This will keep the wheel from being unidirectional when you try to move the trailer by hand.
Operator Controlled Brakes
We have three options here:
- Vacuum over hydraulic brakes. This system uses a source of vacuum from the tow vehicle to operate a brake booster on the trailer, and then the brakes. This is an old system and may require very expensive modifications to the tow vehicle to provide a source of vacuum. Vacuum in an engine is created by air flowing through a carburetor. Today’s tow vehicle tends to have fuel injected or diesel engines, thus poor vacuum sources. Negatives are brake application delay times, and no adjustment for loaded or empty conditions.
- Electric over Hydraulic brakes. This system uses an electric brake controller in the tow vehicle that is the same principle as that used for travel trailers brakes. In this case, our electric current is operating a hydraulic pump, rather than brake magnets. Because of this , we require a cab controller with a high amperage capacity. This is an easy and inexpensive system to install on any tow vehicle, requiring only a source of 12V power.There is a limited range of adjustment on the pump itself, regulating its’ pressure output. There is also a large range of adjustment built into the cab control. The two negatives to this system are cost, and delay time. Because an application of the brake pedal has to start the motor to drive the pump, there is an application delay of .85 to 3.4 seconds, depending on the volume of fluid pumped. i.e.: number of wheel cylinders , state of adjustment of brakes.Neither the Vacuum nor the Hydro-Star are owner-serviceable units, however they both make it easy to flush the brake fluid through the system.
- Straight Electric Brakes. This is identical to the system used in “RV” type trailers, where we have cab control of the trailer brakes. In the past, only painted brake assemblies have been available, which have not been suitable for boat trailers used in salt water.
Fresh Water Flush Kits
Brake Fluid Flushing
- Fluid requirements “ H.D. Dot 3”. approximately 500 ml. (should do a tandem trailer).
- Start with the brake bleeder furthest from the master cylinder, open bleeder about one turn, put short length of hose over bleeder screw and into clear plastic container ( e.g.. pop bottle).
On “Dico “ model 60 actuator, it is possible to pump the brakes by using a screwdriver as a lever. On “Dico” model 6 actuators, a pressure bleeder works best, but if not available, it is possible to make a “tourniquet” of rope between the actuator and the winch assembly to apply the brakes.
Take the cap off the master cylinder reservoir and keep the fluid level topped up while flushing the fluid through the system. This will keep air from entering the system. When clean fluid appears in the drain bottle, close the bleeder and move to next one.
- Loosen wheel nuts.
- Lift trailer until wheel clears ground.
- Support trailer other than on jack, (blocks).
- Remove tire/wheel assembly.
- Rotate hub or brake drum and simultaneously tap the “ Bearing Buddy” with a soft-headed hammer to remove it.
- Remove cotter pin.
- Remove spindle nut.
- Pull out outer bearing.
- Remove hub/drum from axle (pull straight out).
- Remove inner seal- pry out and be prepared to discard, as it should be replaced any time the hub/drum is removed.
- Take out inner bearing.
- Clean the races that are pressed in to the hub/drum. Inspect them very carefully. They should be mirror-smooth, with no signs of discoloration. Clean and inspect the bearings. If all is well, re-pack and re-assemble with a new seal. The factory grease ( as of this date), is “Schaeffer’s 221 Moly Ultra”.
- To reassemble, reverse the above procedures, tighten the spindle nut until there is resistance, then back off the nut far enough to get in a new cotter pin in. Re-install the “Bearing Buddy”.
This bearing loading should be checked after every 100 km. of use, and then annually. The “Bearing Buddies” will need to be greased, as they will fill the voids in the drum under initial use.
The springs are submersed in the water. Consider using an “environmentally friendly” oil.