Camber Pins
These pins are located at the front of the suspension control arm and are visible under the wheel arch in front of the wheel on each side. They appear as a 3cm round disc with a hexagonal bolt head, the disc is welded to the chassis in two positions either side of the disc. They are from a Toyota Prado for replacement purposes. They never need to be removed or greased however they need to be checked for cracks and tightness occasionally.

The exception to this is if you are driving on very rough roads, in which case inspect them every day. Safely get under the trailer and make sure nothing has come loose or been damaged that may cause a breakdown.

The camber pins can be easily checked. The pins are adjusted from new and the cam is welded to prevent movement. The weld is about 20mm long and can crack if the nuts lose their tension. This is one of the service items on the trailer. If the nut comes loose the shaft of the bolt will be then trying to rotate in the housing, only being stopped by the weld. Once the weld cracks, the bolt can shear off by the action of the control arm. Check the welds every couple of days, however it takes a long time for a crack to appear and even longer for the bolt to break.

Pyrometer – Heat Sensing Laser Gun

A Pyrometer or laser heat gun can be used to accurately measure hub, shock absorber, brake and tyre temperatures. They make it very easy to stop on a gravel road and quickly assess how everything is travelling. We use them at AOR to check the brake temperatures for new trailers. An increase in temperature will advise of a potential problem before it occurs. One tyre may be a much higher temperature than the other and may need more air or have a slow leak. It pays to check your 4WD tyres as well. The tyre in the sun all day will usually be warmer than the one in the shade if travelling with the sun mainly on one side.

When checking the shock absorbers, aim the red laser at the lower section of the tubular casing, not the upper section. All 4 shocks on the trailer should be a similar temperature, if not there may be a problem. The trailer shocks will typically be cooler than the 4WD shocks as they do less work.

Hub temperatures should be similar and warm to the touch after driving for some time without using the brakes, sunny side will be warmer. Stop once a day to check these. The brake temperatures will influence the hub temperature as they are in the same hub housing. If you are using the brakes a lot, the hub readings will be elevated and not much use so check as described above.

Brake temperatures differ with wear and adjustment, so usually you are just looking for big discrepancies in temperatures as this indicates differing wear rates and different adjustments. Discs are not adjustable so should remain similar, if not you may have a dragging calliper or handbrake wire may be too tight. Pyrometer available at

Shock Absorber Temperatures

If you don’t have a pyrometer, you will need to safely climb under the trailer and feel the lower section of the tube with your hand. Shock absorbers can get extremely hot so do this carefully. Normally temperatures will be just above an ambient temperature. Differences in temperatures may indicate potential failure of one or more shocks. This only needs to be done once a week if travelling constantly or if you have just done a full day on corrugations.

Wheel Nut Tightness

This is covered in the service schedule but all AOR trailers equipped with either 5 or 6 stud rims are to be torqued to 155nm. These must be checked on new trailers as the wheels, nut seats and hubs all have a layer of paint which they must wear through for the nuts to finally seat home. The nuts are torqued at the factory when new and you are instructed to retighten the nuts every 100km at least 4 times over the next few days. We also suggest you check the wheel nuts occasionally when traveling as they can sometimes come loose on corrugated roads.

You also need to check the wheel nuts after replacing the spare tyre as this is also a new wheel in some cases. If you have the tyres changed at a tyre centre ask them to torque them up and not use a rattle gun. These guns can be set at any torque and can do the nuts up so tight that you can’t get them undone. This can also lead to wheel stud failure.

A good daily check is to look at the outer nut surfaces where they meet the wheel and see if all surfaces are the same depth of colour, if one or two are a slightly different colour they may be slightly loose and gathering a small amount more dust than the others.

Shackles (Tow Bar)

The shackle bolts have no securing device so a visual check of the bolts each time you stop is always good. Check they still appear to be seated home in the housings. Tightening firmly with pliers is advised.

Maintenance of The Anderson Plug

The Anderson Plug carries the 12 volt charge from the vehicle into the trailer regulator for battery charging purposes and is used for the breakaway system in Alko only Disc braked trailers. It requires an excellent connection at all times. Inspect the plug daily for damage, dust build up or corrosion on the terminals. Make sure the terminals are still seated in the correct position as the positioning spring can become distorted with use and allow the terminals to slip back inside the housing. Corrosion will take the form of a white or green powder on the pin mating surfaces. This can be removed by pouring boiling water over the terminals and a scrape with a screwdriver or preferably sandpaper. Once the terminals are clean, apply a liberal coating of Inox/CRC to both plugs and connect them together. Always ensure the two housing are correctly seated against one another.

Anderson Plug – Alko Equipped Disc Braked Trailers

The Anderson plug must NOT come loose or detached at any time as this will activate the breakaway system in the disc brake actuator. If this happens the brakes will lock on and stop the trailer. This can be overridden by pressing the lever at the back of the IQ7 unit inside the front boot, releasing the air pressure inside the brake system. Once the plug is reinserted the brakes will build up pressure and work properly again.

DO35 Coupling Pin

Your tow bar coupling pin should be kept clean and lubricated at all times. Always carry enough rags with you to maintain the pin. It is very important to clean the top groove where the coupling lock seats home and the lower wear face of the pin where the coupling rides. When unhitched always cover the pin with the black rubber cover supplied with the trailer. If you have lost the cover, please purchase another from the AOR store. Once the pin is cleaned lubricate sparingly with the bearing grease supplied in the maintenance kit.

DO35 Coupling – The coupling should be kept clean at all times. This is not always possible but if the locking mechanism becomes too dirty it will not operate properly. When hooking up always ensure the lock slides home into the groove in the Coupling Pin. Clean and lubricate the locking mechanism with Inox/CRC.

Clean and lubricate the coupling pin housing with the bearing grease supplied in the maintenance kit.

Chassis Cracks

This is extremely rare and mainly caused by abuse or severe impact, however it is an inspection that will be carried out at regular service intervals. If these service intervals are not maintained the inspection of the chassis must be done after every major trip.