Field Service Operations and Lubrication

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Contributed Article

Fordson Model N
Field Service Operations and Lubrication
By Anthony West

The daily or weekly servicing of any vehicle is of the utmost importance, and in days gone by when our favorite tractors were doing an important and Commercially vital job on the farm, these service operations would make a major difference to the running costs and economy of the farm. This being so, it surprises me to see how many enthusiasts attending rallies, shows etc, seem to be unaware of the importance of this constant attention. Possibly the modern machine with its 6,000 mile or even once a year service requirement has lulled them into a false sense of security. Maybe the fact that the machine they own no longer does a hard days work, has lead them to the impression that the service period maybe extended or even forgotten about. The true fact of the matter is this. Today's costs incurred when a tractor is restored can be quite considerable and yet many owners still run the wrong lubricants or use unsuitable cooling water, often... either through lack of awareness or complacency they will say we don't put fluid in the air cleaner "it runs okay without" or its only had this oil in two months and all it does is run from here to there!.

What we do with and how we restore and treat our machines is very much our own affair, but this article for those with an interest, is aimed at collectors who wish to get the best of and longest life from their tractor.


The Fordson Model N engine, has no pressure lubrication system and relies solely on "splash" caused partly by dippers on the big ends collecting oil from troughs in the sump and partly by the motion of the tractor. Thus when the tractor is stationary and engaged on "Belt work" it is doubly important to keep the sump up to the correct level on the dipstick.

The life of a Fordson, as with any splash lubricated engine, can be greatly shortened by running the engine with the oil level only a little below the dipstick "L" level. When running the engine on vaporizing oil it is most important to drain the sump every 50 hours and refill it to the correct level, with oil of the correct grade (which in the owners manual is classed as S.A.E 30 or equivalent.)

The choice of oil is a difficult one these days, there is some evidence to suggest that modern detergent rich oils can corrode the old fashioned bearing metals, it must also be obvious that these oils which carry the carbon and other pollution in suspension cannot work correctly without a modern sophisticated filtration system to remove these bodies, a filtration system in fact which most vintage tractors do not have. With these facts in mind consideration should be given to obtaining an SAE 30 oil which contains only a slight rust and oxidization additive.

The only filter on the Fordson tractor is the one accessible when the plate is removed from the base of the sump, in fact this is more of a sludge trap than a filter, and is in fact nothing more than a gauze screen. It should also be noted that the engine is designed with a "dam" which when the oil is circulated in normal operations retains the oil passing it through this filter. If the oil becomes to thick it goes without saying that the filter will become clogged and the oil will spill back over the dam and into the sump where it will be re-cycled UN-filtered and reduce your engines life.

It is therefore recommended that the sump strainer be removed and cleaned with paraffin at the same 50 service interval. Do not forget to re-oil the filler cap wire wool every 50 hours too, or the sump back pressure may cause oil leaks, usually shown up at the front crank shaft seal, valve cover and magneto platform seal.

If you experience oil leaks at these locations always suspect the oil filler cap of being dirty and not breathing correctly

Cooling System

The engine is cooled by the circulation of water in the jackets round the cylinders. The heated water flows by thermo-syphonic action, assisted by a pump at the front of the cylinder head to the radiator, and as it flows downwards through the radiator tubes, it is cooled by the stream of air induced by the fan placed behind the radiator.

On later models a radiator callormeter, or temperature indicator, is fitted to the cast radiator top and enables the operator to see at a glance if the cooling water is at the correct temperature. For efficient operation the indicator needle should be within the white sector.

Clean the water daily or more often if working hard. On cast water jacket systems holding alot of water, it will be impracticable for cost reasons to use anti-freeze, but on other makes or models, particularly with high corrosion prone aluminum components in the cooling system, anti-freeze should seriously be considered for its corrosion inhibitor as much as its anti-freeze properties. in any case, clean the system out by thoroughly hosing out once each year.

Water Pump

Use the correct water pump grease, ( some Fordsons have a screw cap which has to be turned clockwise, whilst some have a nipple which is located on the side of the pump body) use a small amount day. Whilst doing this check there is 1" play on the fan belt and adjust as required.

Grease Nipples

All nipples marked "D" on the accompanying picture should be greased daily, all marked "H" should be greased every 50 hours running.

Steering Box.

On Model "F" and "N" tractor with the large water filled air cleaners the steering is lubricated partly by grease nipples and partly by sump "Fumes". On oil filled air cleaner models 1937-1952 the steering box is oil filled and should be filled to the level of the filler plug with 140 Gear oil. The level should be checked every day-drain and refill every 200 hours. Never run the tractor without oil in the cleaner or with hoses missing or damage and engine wear will accelerate by a very high proportion. Water filled cleaners have the level checked twice daily and be drained and flushed weekly.

Rear Transmission

The Fordson Gearbox and rear axle is a common chamber, the recommended lubricant was E.P 140 viscosity oil, this meant a thick glutinous liquid not at all like a model 90/140 oil which is quite free flowing. This free flowing characteristic is one of the problems modern oils present to us, and this is one reason why the Fordson is often difficult to get into gear!. The old thick oil really caused heavy gear drag, which helped tremendously to free the clutch on cold mornings.

The old 140 oil was so thick that when repairing the tractor in winter I've heard tell of farmers having to put a 5 gall. drum on the top of the primus stove 2 hours before it was needed to be poured into the tractor. So for the best result run on thick gear oil, E.P 140 (not 90/140), it is not quite as thick as the old stuff but it is the best that is available. Check the oil level every 5 hours and change It every 300 running hours.

Dependant on whether there is a call for or demand for this type of information I may consider outlining general repair and maintenance articles which will cover a number of topics from the Fordson service manual aimed specifically at the Fordson tractor owner. They will incorporate any topic considered to be of interest accompanied with pictures from the service handbooks and other period information. For now though may I wish you all safe and happy mendings from the UK.

old style brochure showing all components of a Fordson tractor

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