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HINTS ON MAINTENANCE.

28th February 1928
Page 72
Page 72, 28th February 1928 — HINTS ON MAINTENANCE.
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Withdrawing Associated Daimler Cardan-shaft Couplings. Arresting Oil Leakage on the Peerless. How Slip on the Foden Pump Drive can be Cured.

Removing Cardan-shaft Couplings on the Associated Daimler.

THE flanges utilized on certain Associated Daimler chassis for the Spicer-jointed propeller shafts are sometimes difficult to remove, as they hold firmly to the splines after the securing nuts have been released.

The ordinary form of withdrawal clamp can be used if care be exercised, but if too much power be applied the flange may be bent and the dogs may slip off, whilst there is no room to work behind the flange with a hammer and drift.

In such cases use can be made of a jack of the Wotan type which is usually found in workshops and garages, and, in some instances, is carried on the vehicle itself. The bottom of this should be faced off In the lathe and eight holes drilled and tapped to correspond with the coupling to be withdrawn, the jack then being bolted to the face of the coupling by eight setscrews. If necessary, packing can be inserted between the screw of the jack and the screwed end of the splined shaft.

It is unnecessary to turn the jack screw except to tighten the packing, the pulling off being" done by the setscrews, which will move the coupling for about 1 in. and release it sufficiently to permit it to be tapped or drawn off ; should it still be tight, longer setscrews can be employed and further packing inserted between the shaft and the screw of the jack.

When the time comes for replacing the coupling it will be found that if it be slightly heated and quickly pushed home on to the shaft before the latter is also allowed to become warm • it will grip most securely and there will be no need to resort to driving on.,

Preventing Oil Leaks at the Front End of the Peerless Crankshaft.

AFTER considerable service a serious oil leak may be observed around the front end of the crankshaft

where it emerges from the timing-case cover. If tightening the gland nut or inserting fresh packing does not stop the leak the timing cover must be removed. The trouble is generally found to be either stripped threads in the aluminium or the cast boss—against which the oil-retainer felt presses—inside the cover has fractured. Save for this defect the cover is quite all right and otherwise serviceable.

The difficulty can be overcome by setting the cover upon the lathe and cutting the boss back to the level of the case. A brass collar of the same size and thickness as the original boss should then be turned up and secured in place by four setscrews. When the B46 threads in the cover are badly worn a fresh thread should be cut and an oversize gland nut fitted. This method will prove entirely satisfactory and considerably cheaper than fitting a new timing-case cover.

Curing Slip on the Feed-pump Drive of the Foden.

THE boiler feed pump on the latest Foden wagons

is driven by a friction block, keyed to the crankshaft, in conjunction with a friction disc on a stud bracket fastened to the hornpIate. In time the driving surfaces become worn, causing the pump to cease working. (This state of affairs is accelerated on hydraulic tipping wagons, for the same pump supplies the tipping cylinder, which demands more pressure than the feed.)

When the friction surfaces have lost their " bite " the gear is usually placed in the hands of an experienced fitter to put matters right, but by carrying out the following instructions a satisfactory repair can be effected in a very short time.

It will be found that the grooves on the lower disc are bottoming in the friction disc on the crankshaft, which means that the sides are not allowed to engage, and this causes slip. This can be remedied in the following way without dismantling any part of the engine.

Take a piece of flat steel 2 ins, by in. and about 2 ft. long and grind one end to a V-shape. Hold it as shown in the upper view and run the engine, pressing down on the tool. 'This will cut away the face of the disc to clear the worn ridge from between the groove, and it will be found that a Tic in. cut is quite sufficient. The chances are that the pump will now work quite satisfactorily, but, if not, a further adJustment will also have to be made.

The cutting, away of the face of the disc allows it to go deeper into the block, and this sometimes necessitates cranking the pump lever to give it sufficient movement. To do this release the small coil spring connected to the operating handle and push the pump lever down as far as it will go. Take a piece of iron about 4 ins. by 1 in. by + in. and fix it between the crankshaft bracket and the pump lever. Crank up the pump lever by means of a strong bar (levering off a block on the chassis).

The cranking should be increased until the grooves in the friction drive are just clear when the pump lever is. resting on the roller and when the operating handle is in the shut-off position.

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