BACK IN PRINT - LEAKS

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To keep the War Wheels Turning

LOOK OUT FOR LEAKS

Timely Attention to Oil, Petrol or Water Leaks may Prevent More Serious Trouble

To operate successfully the car required oil in the engine and transmission units, petrol as fuel, and water for cooling. All these liquids, in varying degree, like to escape from the systems in which they are enclosed, and if they do escape through some weakness in the channels through which they are required to flow, more serious consequences may result. That is why it is important to look out for leaks and to cure them promptly.

Probably the most common typpe of leakage is that of oil, which if allowed to continue may cause wear by reducing the quantity of of lubricant below a safe level. Oil, especially when it is warm, seeps through the various joints if they are in the slightest degree slack, and apart from being a complete waste, will spread over the outside of the engine or gearbox to form an adhesive for dust and grit.

Leakage from the oil sump, disregarding the drain plug, can be caused either by faulty filter-cover or reservoir joint washers or loose nuts or set screws. The renewal of either of the joints when defective is a fairly simple matter. The new joint washer should be smeared with grease on both sides before fitting, and both joint faces between which it fits should be scrupulously clean. Care should also be taken when tightening up the set screws or filter cover nuts, not to force them home too vigorously or they are likely to be damaged.

BACK IN PRINT

Keeping pre-war Austins in great condition, this advice comes direct from the manufacturer.

 

Reprinted from "The Austin Magazine"

June 1944

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Tightening the sump nuts to prevent oil leakage from the engine

The secret of a really effective joint is even pressure over its whole area. For this reason a special order is recommended for the final tightening of the reservoir set screws. Those at the centre should be tightened home first, working alternately on each side to those at each end. This "spreads" the reservoir so that is can engage  evenly with the joint washer.

Some motorists have a habit of over-filling their engines with oil, perhaps thinking that the more there is in the engine the better will be the lubrication. This is an entirely erroneous impression as there is a possibility that the surplus oil will leak into the cluthch and cause that unit to behave abnormally.

Loose union nuts on the various oil pipes will also result in leakage and may affect the oil pressure. For this reason, periodical testing of these nuts is desirable and when on occasion the sump is cleaned out the union nuts on the oil feed pipes and crankcase should also be tested and tightened if necessary, remembering that brass unions must not be treated too drastically with the spanner.

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In fitting a new oil sump washer, grease both sides and ensure that the joint surfaces are clean

Leakage of oil from the valve chamber may be due to the securing studs being loose or a faulty washer. The studs should be tightened evenly so that the cover is not strained in any way. The joint washer on all models except the Seven and Twenty is of rubber and before fitting a new one, if such is necessary, the groove around the inside of the cover into which the washer fits should be smeared with some adhesive jointing composition so as to secure the washer in place. In the Seven, the washer is of cork and will fit securely into its groove without assistance. That fitted to the Twenty is also of cork and needs careful alignment. Also in respect of the Seven, leakage can occure from this cover if it is fitted the wrong way up so that the breather holes are on the lower side.

On models with the cylinder block searate from the crankcase it is advisable to test the cylinder-foot nuts for tightness occasionally, so that oil cannot leak from between the crankcase and the cylinder block.

Leakage from the gearbox is seldom experienced. There is, however, the possibility of the front end cover, or the oil-seal for the first motion shaft, being at fault to allow oil to leak into the clutch-pit and out through the vent at the bottom. In the rare event of this ocurring, the services of a trained mechanic should be sought, as removal of the gearbox is involved.

As far as the rear axle is concerned, visible leakage is also a rare occurrence, but if over-filled, the superfluous oil will either exude through the vents, or leak through the half-shaft casings and find its way to the brake drums, to render the brakes inefficient. Care should therefore be taken not to overfill the rear axle, and after replenishing, the filler plugs should not be replaced until a short time has elapsed to allow any surplus oil to leak out - in this case as a safety measure.

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Petrol leaks from the pump can arise from loose diaphragm screws (at B)

Petrol leakage should always be dealt with immediately. Normally, its only effect is to reduce the m.p.g. and so increase running costs, but if it leaks from a flooding float chamber it may cause cylinder wear by being present in escess in the combustion chamers to dilute the oil on the cylinder walls. Leakage from the carburetter float chamber is usually due to the needle valve, which regulates the supply, not seating correctly. The needle valve is situated under the float chamber cover and can best be removed by means of a ¼ in. box spanner; it can then be examined and ground in with valve grinding compound if it does not seems to be seating efficiently. On being refitted it should be screwed securely home with its fibre washer in position, so that petrol cannot leak round it into the float chamber, which should also make an effective joint with the main casting of the carburetter, the two screws being tightened evenly home. Incidentally, if the float is not replaced the right way up, flooding may be caused by altering the cut-off level.

The other point at which petrol leaks can arise is the petrol pump. This unit may leak round the flange in which the diaphragm is held, but by tightening the six screws this fault can usually be rectified. The top cover is anotehr possible source of leakage and should be screwed down securely onto its cork washer.

As with the lubrication system, there is also the possibility of escape from the various pipe unions and slackness of the union nuts. In dealing with the nuts avoid overtightening them to place undue strain on teh soldered connections.

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it the cover is not fitted securely oil will leak from the valve chamber. At A are the breather holes on the Seven, which should be uppermost

The petrol tank itself is not likely to leak unless it sustains damage, but an occasional verification of the tightness of the drain plug will do no harm.

Perhaps the most vulnerable connection in the petrol system is the short section of flexible piping between the frame and engine on some models with flexible mounting , and the unions at each end of this should be periodically examined to ensure that they have not worked loose.

Water leaks are rendered evident by the presence of rust stains, and constitute a danger in giving rise to engine overheating throug loss of water. They mostly emanate from the rubber hose connections between the radiator and engine. The hose clips occasionally become a little slack and a leak so caused can usually be remedied merely by tightening the offending clip. If this does not have the desired effect, it may be necessary to reajust the position of the hose after draining the cooling water and slackening the clips at each end. If the rubber hose has perished, renewal is the only remedy.

On models fitted with the RP type of thermostat having the "On" and"Off" setting, leakage is possible along the valve spindle if the gland is at all slack. The gland is behind the adjustment disc and can be tightened with a 3/16 in. flat spanner. The same, of course, applies to water pump glands, which in addition require regular lubrication.

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Oil can leak from below the Seven monobloc if the monobloc nuts are not kept secure

Perhaps the most vital of all in respect of water-tightness is the cylinder head gasket. This may develop a leak towards the outside of the engine, or, more seriously, into the cylinders, in which case the engine will in all likelihood cease to function.

Usually a serious leak from the cylinder head gasket can only be cured by fitting a new gasket, but tightening the cylinder head nuts , beginning at the centre and working to the ends, as recommended for the oil reservoir, may prove an effective remedy. If a new gasket has to be fitted, the head and cylinder block joint surfaces should be clean and smooth, the gasket greased on both sides and fitted with the plain side up. It is also a wise precaution to try the cylinder head nuts for tightness a few hundred miles after a new gasket has been fitted, as it is often possible to take them up slightly when the gasket has bedded down.

Other sources of water leakage are the core or welch plugs in the engine and cylinder head casings. Faulty plugs cannot be rendered watertight but must be replaced by new ones. This process is not difficult. With the aid of a hammer and punch should be made through the centre of each plug so that it can be prised clear. The plug hole should then be smeared round with one of the usual jointing compositions to ensure a watertight joint when the new plug is fitted. The new plug itself, which can be purchased from an Austin dealer for a few pence, is concave, and when placed in the plug-hole, hollow inwards, should be an exact fit. It can then be tapped sharply in the centre with a hammer and drift until by expansion it becomes secure. If the offending plug is not readily accessible the cure should be effected by a garage.

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Occasionally the cylinder head nuts should be tested for tightness or the gasket may allow cooling water to leak, perhaps into the cylinders

If water is seen dripping from the exhaust pipe when the engine is warming up it must not be assumed that the gasket is leaking. Such water is a by-product of combustion, having condensed before emerging from the yet cool exhaust pipe. When the engine and exhaust are at normal working temperature the water content of the exhaust is not noticeable as it emerges in the form of steam.

In the event of a leak from the radiator itself, caused perhaps by a slight accident or a stone thrown up from the road, it should be attended to by an expert, as repairing such a leak can prove very difficult to the uninitiated and it is very easy to find the leak worse at the conclusion of operations than at the beginning.

Finally, mention must be made of air leaks, and in this respect we are concerned with air leaking into the induction system and upsetting the mixture to cause difficult starting, or even explosions in the silencer. If these symptoms occur, loose manifold nuts or a bad connections between the carburetter and the manifold pipe should be suspected, although explosions in the silencer will also arise from a leaking exhaust joint.

The majority of leaks of this description can be dealt with quite simply by renewing the joint washers or by tightening the various nuts. The manifold nuts should be tightened evenly, a little at a time, and though they should be quite secure they must not be forced, as they are made of brass and the threads are liable to strip.

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The manifold required to be airtight or the mixture may be weakened, to render starting difficult

After prolonged usage over a mileage sufficient for wear to develop, air may leak into the engine up the valve guides. This will also cause difficult starting and erratic running and the remedy is usually one of valve renewal. Another point at which air leaks can be of detriment is the petrol pump, as air entering this unit above the diaphragm either round the diaphragm flange or the top cover joint, will affect the efficiency of the pump.

It will be seen that the majority of leaks can be cured quite simply by the motorist, and timely attention to them will often prevent more serious troubles.

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Reprinted from The Austin Magazine, June 1944

This article details historic practices that may or may not be relevant an/or correct for contemporary circumstances. Please be sure that any information provided is correct for your application before using on a vehicle.