On MAC only from engine number MAC15523.

The fabric element needs no attention, but should be discarded and replaced by a new one after every 10,000 miles service.

The element is carried in a cylindrical chamber of the oil tank and all oil returned from the engine has to pass through it before going back into the tank.

To remove the element it is unnecessary to drain the tank, but as it is always advisable when fitting a new element to start with clean oil we recommend not only draining the tank but removing it entirely and washing it out thoroughly in clean petrol and allowing it to dry off before refitting.

In order to remove the filter element the return hose must be disconnected from the union nipple below the tank. (This will be disconnected in any case if the tank is being taken off).

Loosen the nut at the top end of the filter centre stud - in the centre of the filter top cap on the tank top - and with a metal pan or dish held below the bottom filter cap prise the bottom cap away from the tank to allow the half-pint or so of oil trapped in the filter chamber to drain away. The complete removal of the nut and top cap will allow the bottom cap with centre stud to be pulled out. Retain the joint washers used between the two caps and the tank. The filter element can now be pulled out.

Wash out the tank as described above.

When dry fit the new filter element and replace the joint washer and the bottom cap, passing the centre stud up through the filter chamber. Have the top cap with joint washer and nut handy for refitting. Hold the bottom cap and oil union firmly against the tank to prevent leakage and pour clean oil of the correct grade into the oil filter chamber from the top. When up to the level of the opening leading into the tank put back the top joint washer, the cap and the nut and tighten this securely. Hold the tank upright and refit to the machine. Refit the drain plug, see that the check valve is in place and refill the tank.

Connect up the oil pipes, being careful to see that the feed pipe is full of oil (see page 13.)

The object of filling the filter chamber is two-fold. Firstly, if it is not filled when the filter is replaced the level of oil in the main tank will be reduced soon after starting by the amount of oil required to fill the filter chamber to the level of the outlet pipe. Secondly, no return of oil would be visible entering the tank after the engine was started until the chamber had filled.