When hot, the bearings in the axle hubs may be subject to water ingress through the axle seals if they are immersed in water during a deep creek crossing. Prior to and after long trips, AOR or an approved service agent should carry out inspection and maintenance of the brakes and hubs.
Wheel Bearing Temperatures
Bearings should be warm to the touch. This check can only apply when you have been driving for a long period without using the brakes as the brakes will heat the bearing so the check becomes inaccurate. Important to note is that they are all approximately the same temperature. When the bearings are new they have a preload which is adjusted at the first service. This allows the bearings to seat home. The temperature difference is an indication of different preloads so this needs to be checked if temperatures rise or are different.
Different temperature can also indicate bearing wear or water ingress from repeated water crossings. Temperatures can be checked with a hand held laser pyrometer (see Touring Maintenance Guide section in your AOR manual).
This is a very important area to understand, because if the bearing collapses, the axle shaft can become damaged beyond repair, necessitating a new control arm.
Water crossings where the bearing shaft is immersed in water are usually fine, but it is never advisable to stop in the crossing with the axle immersed in water. Doing this causes a rapid change in temperature inside and outside the bearing seal which can draw water into the bearing housing. This itself, is not a big problem but should not be left unchecked. It is easy to see if the bearing has absorbed water by removing the bearing cap and checking the consistency of the grease. It should be black or look like new grease and be sticky to the touch. It should not be runny, light grey or white in colour. This is also a good time to check preload.
Removing The Wheel Hub
- Undo the wheel nuts and remove the wheel.
- Unbolt and remove disc, callipers or drum.
- Pry off the dust cap using a flat bladed screwdriver.
- Straighten out the cotter pin that holds the bearing nut and remove it.
- Remove the bearing nut and washer.
- Gently pull the brake hub or disc forward while cupping the hub opening with your hand to keep the front bearing from falling to the ground, the inner bearing stays in the hub until the grease seal is removed.
- Place the front bearing, bearing nut and the bearing washer in a clean container.
Removing The Grease Seal and Rear Bearings
- Place the brake disc face down so that the back of the hub is accessible.
- Pry out the grease seal. This will be replaced in a further step.
- Lift out the rear bearing and place it in the container with the rest of the parts.
- Do not mix up the bearings if you are doing more than one wheel at a time – each bearing must mate with its original race. The bearings wear in by a certain amount and need to be matched with their respective counterparts.
- Thoroughly clean the bearings and other parts in a solvent (not petrol!) until the old grease is removed. Allow to dry completely or blow dry with compressed air. Do not use the air pressure to spin the bearing, as this may cause damage to the bearing.
- Clean the hub and spindle.
- Inspect the bearing and bearing races for heat discoloration, pitting, scoring and any unevenness. Any out of round rollers, cracked roller cages and rough running will indicate replacement is required.
- The bearing and both inner and outer races must be replaced as a set.
- Inspect the brake discs for pitting and excessive wear, especially if they have been allowed to wear down to bare metal.
Hand Packing the Bearings
- Place a walnut sized dollop of wheel bearing grease in one palm.
- Grasp the bearing with the other hand so that the wider end is facing the grease.
- You need to force the grease into the gap between the inner race and outer cage so that it squeezes up through the rollers and out the top.
- Press bearing down into the grease in a rocking motion and continue until the grease oozes up.
- Rotate the bearing 1/4 turn at a time and continue until bearing is completely filled with grease.
- Place grease into the interior of the hub with your fingers. A walnut sized amount is sufficient. Spread it around the inner circumference of the hub.
- Place the inner packed bearing into its place in the hub.
- Place a new seal on the hub and tap it into place with a hammer until it seats fully.
- Be sure to wipe off any grease that finds its way onto the outer flat surface of seal.
- Replace the hub onto the axle spindle, insert the outer bearing, thrust washer and axle nut.
Preloading The Bearings
- Tighten the axle nut by hand until it is tight then tighten another 1/8 of a turn.
- Spin the disc several times to distribute the grease evenly in the bearings, whilst loosening and tightening the axle nut.
- Back off the nut with a spanner until loose and then retighten finger tight. Tighten to the next castellation where the cotter pin will fit.
- Insert a new cotter pin to lock the nut in place and bend it over the spindle.
- Re-install the dust cap and wheel.
Replacing The Bearings
- The bearing must be replaced with a complete new bearing with the inner and outer races.
- The inner races are pressed into place in the hub and must be driven out.
- Use a brass punch to catch the edge of the race by passing it through the inverted hub. Several blows with a hammer should drive out the old race.
- Place the new race into position and tap it in with the hammer and punch. Take care not to mark the surface of the race. Pack, reassemble, and preload the bearings.
CAUTION: Stop or pause to allow cooling of your hubs and bearings before water crossings. This may prevent ingress of water through wheel bearing seals. Do not stop in a water crossing if the water is up over the axle.
Disc Brake Equipped Trailers (Alko Only)
If your trailer is fitted with disc brakes, the IQ7 brake control unit is mounted in the right side of the front storage box. This unit has a sight glass on the front of it so you can monitor the brake fluid level. The brake fluid should be flushed out and changed every 50,000klm or once a year whichever is sooner.
NOTE: When getting your trailer serviced by a service agent ensure they lubricate the disc brake calliper slides. If it becomes necessary to shift the trailer without attaching it to your vehicle, the pressure in the IQ7 brake control unit can be released by depressing the lever situated on the rear of the IQ7 unit.
NOTE: Ensure the Anderson plug does not get snagged or pull out at any time while driving as the trailer brakes will fully apply and stop the trailer. In doing so the breakaway system has been activated.
Breakaway Switch For Drum Brake Models
Make sure this switch is working properly by activating the switch once you are hooked up. It is a good idea to check its operation occasionally. Ensure the cable connected to the vehicle will have enough slack when the rig is articulated, if the cable tightens then the switch may activate. It is important to make sure this cable is not hanging down where it can get snagged by rocks or sticks on tracks. If the cable pulls the switch on your trailer brakes will lock on, stopping the trailer.
Trailer Plug – Drum Brake Trailers
Each time you stop ensure the trailer 12 pin plug is secure and the wires are nowhere near the ground where they can be snagged. The male and female terminals in both plugs should be sprayed with CRC/Inox lubricant regularly to ensure good connectivity. If you are having trouble when hitching up getting the lights to work, remove the male plug and open up the 12 pins slightly with a small screwdriver. Push the plug in and out of the housing several times to ensure good connectivity. These pins close up over time and need constant cleaning, adjustment and lubrication.
This can be adjusted underneath the handbrake mechanism by unlocking the locknut and turning the small hand wheel. Tighten the locknut after adjustment. The handbrake on drum brakes should lock up at 5 clicks. For disc brake models the handbrake will lock at 8 clicks. The handbrake can be lubricated occasionally to ensure smooth operation.