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The only acceptable method of applying the correct wheel bolt torque is a calibrated manual
torque wrench.
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Lower the trailer and remove the jack.
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DO NOT DRIVE ON AN UNDER INFLATED TYRE.
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After any wheel refitting wheel bolt torques should be checked after approximately 25 miles.
Wheel bolt torques are 110 Nm (81 lbf. ft) for 5-stud wheels or 88 Nm (65 lbf. ft) for 4-stud
wheels.
5.7.3
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Wheel Bearings
5.7.3.1
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Wheel Bearing checking
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Unlike car wheel bearings, which run with pre-load and have no measurable play, Ifor
Williams’ wheel bearings always have free play. At the extreme end this can seem quite
alarming but actual measurement, as described below, almost always shows it to be quite
small. No other procedure is accepted by the Company.
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Many wheel bearings are replaced un-necessarily with the only result that the hub
bore is enlarged during removal and refitting and the replacement bearing then comes
loose.
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Tests by the Company and our bearing supplier show hardly any reduction in life for bearings
with far more clearance than is permitted by this procedure.
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Conversely, bearings which are too tight can show a dramatic reduction in life.
5.7.4
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Brake Cables
5.7.4.1
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Brake Cable Inspection
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The construction of the brake cable is as follows: outer plastic sheath, spiral steel case, thick
nylon sheath, inner steel cable. Local wear of the outer plastic sheath which exposes the steel
spiral has no effect on the function of the brakes. Only if the steel spiral case is penetrated is
urgent replacement needed.
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Brake cable should move smoothly and equally when the handbrake is applied. If the coupling
head is moved from side to side with the handbrake applied (and the trailer wheels on the
ground), so that the wheels on both sides are forced into auto-reverse further equal
movement should be observed.
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If, at either stage equal movement is not observed then it is possible that water ingress has
caused the cable to rust, swell and sieze. However, it is most likely that the brakes are out of
adjustment, so the first step is to reset the brakes as described in the Knott leaflet.
