By Staff
1 / 6
Removing the dash.
2 / 6
New Fordson brake assembly.
3 / 6
Tractor split and method of blocking up sections.
4 / 6
Finding play between piston and cylinder walls with feeling gauge.
5 / 6
Installing split keys on transmission shaft over which the clutch fits.
6 / 6
Method of holding differential while removing worm wheel.

Suggestions That Will Enable Tractor Owners to Keep Their
Machines in Best Order and Prolong Their Life

Author: F.M. Service, Reprinted from Farm Mechanics February and
March 1925. submitted by Dick Hamp, 1772 Conrad Avenue San Jose,
California 95124

In the following article we have recommended the replacement of
all parts that were found to be badly worn, etc., though they may
in some cases be still usable, because the cost of the replacements
is so low that the satisfaction of a job done right, together with
the increased efficiency of the tractor, will more than offset the

It will be found that we have started in at the first operation
of a complete overhaul and have followed through with each unit as
it is removed in the sequence of tearing the tractor completely
down, and have given as complete a description as space would

Fuel Tank:

This is the first part to be removed. Take off the nut on top of
the steering wheel spider and remove the wheel from the splined
shaft by tapping from the bottom. It is necessary to take the wheel
off to give clearance to the fuel tank. Disconnect the kerosene
line from the sediment bulb, and remove the four
3/8 -inch nuts holding the tank straps to the
radiator and the dash. The tank can then be lifted off. Drain out
the kerosene in the tank and remove the sediment bulb on the
bottom. Put a quart of kerosene back in the tank and splash it
around, holding your finger over the sediment plug hole. Now drain
it off. This is to remove any dirt that may be in the tank. If
there are any leaks, they can be repaired by soldering. Next take
apart the sediment bulb and clean off all dirt. Also clean the
small screen in the feed line cap. In replacing the fuel tank, the
lining on the straps must be replaced if not in good condition, as
a metal to metal contact will cause friction that may develop a
leak later. All tractors manufactured after June 1, 1924, are
equipped with the gasoline tank as part of the kerosene tank. This
is accomplished by placing a partition in one end of the fuel tank,
which permits the holding of ? gallon of gasoline for starting
purposes. The small iron gasoline tank is thus eliminated. These
new style tanks are interchangeable with the old style.


It is not necessary to remove the radiator unless there are
leaks in the tubes, and if there are leaks that cannot be reached
easily by a soldering iron, remove the radiator by disconnecting
the four bolts holding the outlet to the cylinder head and the
three cap screws holding the bottom tank to the cylinder front
cover. To remove a leaky or damaged tube, take off the top and
bottom iron tanks by removing the small bolts and nuts holding the
cone outer shells and tanks together. The core can then be removed
and the damaged tube unsoldered from the top and bottom core
plates. With a pair of pliers the old tube can be pulled through
the fins and a new one inserted which must be soldered to the top
and bottom plates. In assembling the radiator, care must be taken
that the gaskets are in good condition and shellacked to keep them
water tight.

If there are no leaks in the radiator, it would be well to flush
it out thoroughly and if any tubes appear to be stopped up, run a
piece of soft copper wire though them, as they are being

Air Washer:

The only part that ever needs repairing or replacing is the
float. To inspect this, remove the cover of the air washer by
disconnecting the main air supply flange and the four cover bolts.
If the fuel tank is off, the float can then be lifted out and
examined. If the floats are badly collapsed or dented in on the
bottom, caused by operating the motor with insufficient water in
the air washer, they must be replaced with new or they will settle
too deep in the water. If the floats are not dented, shake them to
see if there is water in them, and if there is this must be removed
and the leak soldered up. Before replacing see that the bowl is
clean and in assembling the cover, etc., renew the gaskets if they
are not in good condition.

Splitting the Tractor:

In order to inspect the clutch and transmission it is necessary
to split the tractor or disconnect the engine from the
transmission. The first thing to do is to remove the steering wheel
and fuel tank as described above. Then remove the two cap screws
from the cylinder head holding the clips to guide the spark rod.
Remove the two cap screws fastening the air washer to the dash and
the two screws holding the dash to the transmission cover. Also
remove the small gasoline tank when taking off the air washer. To
remove the dash, take out the two remaining screws fastening it to
the transmission case, and after disconnecting the drag link on the
steering arm wall, the dash can be lifted off. Very little trouble
is ever experienced with the dash and its parts, though it would be
a good idea to be sure that the clutch lever and steering pinion
are tight on their shafts. If they are loose they can be tightened
by riveting the pins and replacing the keys. The tractor is now
cleared off and ready to split, but first the two sections must be
supported when they are pulled apart. To do this, block with heavy
timber the front end just back of the connecting flange and high
enough to hold it in its original position. Next place a jack under
the rear end about 8 inches from the front flange of the
transmission housing and then in front of the jack, block up with
timber to the same height as the front end. The jack is to raise or
lower the rear end, if bolt holes, etc., do not line up in removing
or assembling. The engine must now be blocked from both sides so it
will not roll over on the pin holding it to the front axle when the
tractor is split. To do this wedge-shaped blocks can be placed on
the front axle between it and the front cylinder cover. Now remove
all the bolts and nuts in the flanges, and the rear end of the
tractor can be slid out of the way. It is best to remove the rear
end instead of the front, as it is lighter and can be more easily

Grinding The Valves:

Remove the cylinder head by taking out the four bolts connecting
the radiator inlet to it, and all the long cap screws fastening it
to the engine block. It can then be lifted off with the gasket.
Inspect the cylinder head gasket carefully before laying it aside,
and if there are any tears or flat spots in it, it must be replaced
with a new one or loss of compression will result. Next clean off
all the accumulation of carbon on the cylinder head, the valves and
the pistons. This can be done with a knife or screw driver. To
remove the valves, take off the valve cover on the right side of
the motor block, which is held in place by two cap screws. The
valves are removed by lifting up the valve spring with the tool and
pulling out the little pins under the valve spring seat. The valve
may then be lifted out by the head. For grinding the valves, use
any well advertised brand of valve-grinding compound. Put the
mixture sparingly on the bevel face of the valve and put it back in
the valve guide it was taken out of. Of course if the valve does
not go all the way down to the seat, the motor must be turned over
until that valve is down. Now rotate the valve back and forth about
one-quarter of a turn at a time, in each direction, using a
grinding tool. Constantly lift it slightly, changing the position
of the valve as it is turned. Every two or three minutes remove the
valve and wash the face and valve seat in the cylinder with
kerosene and inspect the surface being ground. Continue to grind
with a new application of grinding paste, until the bearing surface
is smooth and bright, and no small black spots remain. If the valve
seat on the cylinder block appears to be seamed or badly worn, it
is best to reseat it with a valve seating tool, which is simply a
reamer made to the exact bevel of the valve face. The operation of
reseating requires some skill and is best done by an experienced
mechanic, for if the reamer cuts too deeply it would be necessary
to retime the valves.

After the valves are all ground, the clearance must be inspected
between the valve stems and the push rods. When the valve is closed
the correct space is never more than 1/32 or less than 1/64 of an
inch. There is no way of adjusting this clearance, but if the valve
stem is too close to the tappet, file it off until the correct
distance is had, and if the clearance is too great the valve had
best be replaced with a new one.

The cam shaft, cam shaft bearings and valve tappets will
ordinarily outlast the rest of the tractor, though it would be well
to inspect them carefully and if excessive wear has developed, they
should be replaced. This also applies to the timing gears, where
very little trouble ever develops.


Reblock the engine under the fly wheel and remove the front
radius rod. Next remove all the bolts and nuts holding the lower
crankcase to the cylinder block. After these are removed, if the
case does not come down easily, pry gently with a screw driver, as
it may be stuck with shellac. After the crankcase is off, wash it
thoroughly and lay it to one side. Now with a prick punch mark all
the lower bearing caps on the connecting rods and the rods
themselves. These marks should be placed on the side toward the cam
shaft, marking the connecting rod nearest the radiator with one
punch and the next one to it with two punches, the next with three,
and the last with four. The purpose of doing this is to insure
getting both the rod and the cap back just as they came off. The
three main bearing caps that bolt to the cylinder blocks must also
be prick punched on the cam shaft side. Number one being nearest
the radiator and number three at the flywheel end.

Main Bearings:

Remove each main bearing cap and fit up separately. Start at the
front bearing and remove the cap screws and carefully lower the
bearing cap. Between the halves of the bearing are a number of
brass shims about .003 of an inch thick. Remove one of these from
each side at a time and put back the cap and bolt up tight. Then
test the tightness of the bearing by turning the motor over with
the crank. If the crank cannot be turned with one hand, the bearing
is too tight and you have removed too many shims, so one must be
put back on each side and tested with the crank again. If, on the
other hand, the crank seems to turn too easily, take out another
one on each side. If there are no shims in the bearings a fit can
be had by carefully filing off the bearing cap, being sure to file
it perfectly square. Do not take the bearings up too snug, or by
the time all the main bearings and connecting rods are fitted, it
will be impossible to start the tractor. After the first bearing is
fitted to your satisfaction, loosen it up and proceed to adjust the
center one. Then loosen that and fit the rear one. On this bearing
depends the adjustment of end play which keeps the magneto on the
flywheel the correct distance from the magneto coil, and if the
crankshaft can be moved back and forth more than .010 of an inch,
replace the bearing cap with a new one (part No.2565), which will
remove the excessive end play. Always be sure when the bearing caps
are being put up for the last time to oil the surfaces of them well
or the metal is liable to cut before the oiling system can
lubricate them. After all bearings are fitted, loosen them up and
proceed with the rods and pistons.

Pistons and Connecting Rods:

To remove the pistons and rods turn the motor so as to bring the
first piston to the bottom. Then remove the cotter pins in the
connecting rod bolts and remove the two castle nuts. If the lower
half of the bearing does not come off easily, tap it gently with a
hammer and be very careful not to drop or misplace any shims that
may be found between the two halves. Now push the connecting rod
and piston up so it is clear of the crankshaft, and replace the
lower half of the bearings exactly as it was when on the
crankshaft, being sure the prick punch markings are the same as
they were and that the shims are in exactly the same place as they
were before you took the bearing cap off. The rod and piston can
then be pushed out of the top of the cylinder. Repeat the operation
with each one of the three. Next remove all the piston rings from
the pistons by inserting a knife or the handle end of a small file
under the ring near the break or end, and raise up above the
groove. Then press that end of the ring out of the groove and run
the file or knife around the piston under the ring until the ring
has been completely lifted out. Lay the rings in separate groups so
you will know from what cylinder they were taken. Take the piston
and, holding it by the rod, insert it in the cylinder it was taken
out of, and with a set of feelers see how much play there is
between the piston and the piston wall. If there is more than .006
of an inch play the piston is very likely to slap and it should be
replaced with a new oversize one to eliminate the wear. The only
oversize pistons obtainable are .0025 of an inch larger than
standard, and if when these are tried in the cylinders they should
stick, it will be necessary to lap them in, by using a mixture of
fine valve grinding paste thinned with oil. This is smeared on the
piston which is then worked up and down on the cylinder and
revolved back and forth at the same time. When it will pass
entirely through the cylinder remove all grinding compound from
both the cylinder and the piston, with gasoline, using great care
to see that there is none left to cut the walls when the motor is

Whenever new pistons are fitted, new rings should also be
installed and if new pistons are not necessary be sure and try each
of the old rings in the cylinder it came from by inserting it in
the cylinder and measuring the gap where the slanted ends of the
ring come together. If this gap measures more than .008 of an inch
install new rings, being sure in putting them on the piston so that
the small punch mark or the word ‘Fordson’, that will be
found on the flat side of each ring, is placed up in each piston
ring groove. This mark is placed by the manufacturers to identify
the bevel of the ring surface, and if placed on the bottom will
cause the motor to pump oil. If on fitting new rings it is found
that when placed in the cylinder the gap is too small it can be
made larger by filing. This gap must never be under .004 of an
inch, to allow for expansion from heat. Also run each ring around
the groove in the piston it is to go on and be sure it will move
freely all around.

To test the wrist pin for excessive play, place the connecting
rod firmly in a vise and holding the piston in both hands try to
tip it back and forth. If there is any play it will be felt and a
new oversize pin should be installed. To do this run a rod through
the hole in the wrist pin and place in a vise. Then remove the cap
screw that clamps the wrist pin. In fitting a new wrist pin, it
must not be so snug that it cannot be turned with the fingers.
After the necessary repairs are made to the pistons and the
connecting rods have been put back on, place the pistons in the
cylinders they belong in and proceed to fit up the connecting rod
bearings in exactly the same manner as the main bearings. If it is
found that there are no shims between the halves of the bearings
you can file off the lower cap, until the proper fit is had, but be
sure and file evenly or the bearing will be out of line when it is
finally fitted. Tighten up all the main bearing cap screws and
connecting rod bolts and nuts, and try to turn the motor with the
crank. If the bearings have all been taken up correctly, you should
just be able to turn it over with both hands. If it is all right,
rewire and cotter pin all bolts as they were and then replace the
crankcase, being sure that the gaskets are in good condition and
will be oil tight. Next replace the cylinder head and the motor is

It might be well to mention here some of the repairs which the
layman would not be able to handle without special equipment and,
if found when the motor is being overhauled, had best be taken to
the nearest Fordson service station to be done. First, if the
cylinder walls are found to be badly scored or out of round the
cylinders must be rebored or reground or efficient results cannot
be had. If this is found to be the case it must be sent to the shop
for reboring and fitting of oversize pistons. Second, when the
crankshaft and bearings are being inspected, if the shaft appears
to be badly ridged and worn, it must be reground or replaced with a
new one, otherwise you could not keep a tight bearing in the motor.
Third, if the upper main bearings appear loose or burnt, they must
be replaced. This will necessitate the removal of the cylinder
block, as the bearings are cast directly in it.


If no trouble has been experienced in the past with the magneto,
it is advisable not to touch it except to see that all the cap
screws and clamps are tight. However, if the magneto is weak or has
given trouble, it had better be tested. Remove the six nuts on the
flywheel studs and the flywheel can be removed. The field coil can
then be taken off by taking out the cap screws that hold it to the
cylinder block. To test the magnets to see if they are of the
proper strength, remove them from the flywheel, great care being
taken that they are laid down in the exact position as they were on
the flywheel. Then take each magnet separately and if it will hang
suspended from a bar of iron or steel it is all right. If any are
found to be weak the entire set should be replaced. They can be
turned in for a new set and an allowance is given on the price of
the new ones for the ones returned. When they are being reassembled
on the flywheel they must lie so that their opposite sides are
together, or, in other words, so no magnet will stick to the one
next to it. The field coil should be tested for shorts in the
winding by disconnecting the ribbon wire where it is grounded to
the coil frame. This can be broken away by a sharp cold chisel.
Then connect one end of a storage battery to this wire and with a
wire connected to the other terminal of the battery rub on a bare
spot on the iron of the coil frame. If you get a spark, the coil is
grounded in one of the sixteen spools and should be replaced with a
new coil assembly, as a practical job of repairing cannot be done
on the grounded one. If, however, you do not get a spark the coil
is all right. The ribbon wire can then be soldered in place, and
the magneto can be reassembled to the motor. With the coil and
flywheel in place, the faces of the magnets must be separated from
the surface of the coil spool by 1/32 of an inch. The correct
distance can be had by shimming out the field coil from the motor


Remove the coil units from the coil box on the side of the
engine and inspect the points. If they appear to be worn or pitted
replace them with new. If the pits are small on the points they can
be removed with a fine file. In adjusting the points turn the
adjusting nut so that when the spring is held down the gap between
the points will be a little under 1/32 of an inch. Then set the
lock nut so the adjusting nut will not vibrate loose. The spring
should have enough tension so that it will spring back sharply when

The wire loom connecting the coil box and the timer should be
carefully looked over and any place where the insulation has been
worn off must be taped up. If the wires appear to be badly worn and
oil soaked they had best be replaced with new.

Remove the timer and inspect the shell and roller, and if the
shell is worn out of round or has ridges in it, replace with a new
one. The roller should also be replaced if worn badly enough to
wabble on its shaft. Always be sure that the roller arm has enough
spring or tension to it to bring the roller in positive contact
with the contact surfaces on the timer shell. This tension can be
increased by placing a screw driver in behind the roller and prying
out, bending the roller arm and extending the roller. It has been
found to be good practice to pack the entire timer shell with soft
cup grease which will lubricate it for a considerable period.

The spark plugs should be taken apart and the porcelain examined
for fine cracks. These can easily be found by loosening the small
nut on top and tapping the porcelain gently with a pair of pliers.
If there is a crack the porcelain will fall apart and should be
replaced. In assembling the plugs be sure and tighten the small nut
and replace the gaskets under the large hexagon nut. The distance
between the sparking points should not be more than 1/32 of an inch
or about the thickness of a smooth dime.


The clutch used in a Fordson Tractor is of the multiple disk
type operating in oil and it is non-adjustable. The only troubles
experienced is the clutch slipping, due to weak clutch springs or
worn plates and the clutch sticking or not releasing properly which
is generally caused by bent or warped plates. To remove the clutch
after the tractor has been split, simply pull out the cotter pin
and remove the large hexagon nut on the clutch shaft. The clutch
can then be withdrawn from the shaft. Before housing and the
clutch, drum flange with two clamp screws so that when the bolts
have been removed the clutch will not fly apart and injure the
operator. After the bolts are out relieve the pressure on the
‘C’ clamps and the clutch can be taken apart. Remove the
plates and inspect them. Their surfaces should be smooth and
bright, and if any plates appear to be scorched or have bumpy
surfaces, they should be replaced with new ones. Test all plates
for trueness of surface and replace plates that are warped. Inspect
all the springs, and if any are shorter than the others it is best
to replace them. If any trouble has been experienced with the
clutch slipping and the plates appear to be in good condition, it
is recommended that all springs be replaced with the new style
150-lb. pressure  ones, which can be obtained from your
dealer. In assembling the clutch, place the plates in the drum
alternately, starting and ending with a large plate. Before drawing
all the bolts and nuts tight, line up the small plates so they will
fit over the flywheel studs easily. After the bolts are all tight
be sure and replace the locking wire through all of the eight

Brake:This is known as a transmission brake and
operates when the clutch pedal is depressed beyond a point where
the clutch releases. This compresses the brake plates, of which
there are three, two being stationary and one rotating, and they
grip the idler gear, causing the tractor to stop. About the only
repairs that ever need to be made is to adjust the brake when it
becomes loose. This is done by removing the foot bracket at the
side of the transmission housing and turning up on the brake
adjusting screw. The brake comes out complete with the transmission
plate and gears as described above and can be disassembled and the
plates inspected when the gears and bearings are removed. It is
very seldom that the brake plates become worn enough to need
replacement, but they should be inspected and if badly worn
replaced. When reassembling the brake be sure the head of the
adjusting screw points to the front of the tractor and the foot on
the front end of the brake shaft points upward where the head of
the adjusting screw will strike it.

The brake is only standard equipment on the late model tractors,
but can be installed on all models by replacing the necessary
parts, a list of which can be obtained from our Fordson dealer.


To remove the transmission it is first necessary to drain the
transmission oil by taking out the drain plug just under the
shifter cover. Then remove the gear shifting lever by taking out
the four cap screws holding it and the cover to the transmission
housing. Next pull out the locking wire and remove the eight cap
screws that bolt the transmission plate to the housing. Then by
pulling on the shaft that the clutch was on, the transmission plate
with the lower transmission shaft will come out, and the upper
shaft with its gears can be pulled out next. Clean all the parts in
kerosene and carefully inspect all the ball bearings. If any of
them do not run true or have side or up or down play in them they
should be replaced. The gears that show signs of bad wear should
also be replaced with new ones. To remove the gears or bearings
from their shafts requires the use of an arbor press and special
arbors and if any such work is necessary we would recommend that
you have it done at the nearest Fordson service station. About the
only trouble that is experienced outside of bearing trouble is the
gears coming out of mesh when in speed. This can be caused by
several things, namely, sprung transmission shafts; too much play
between the shafts and gears; worn gear teeth and a bent shifter or
weak locking pin on the shifter. These causes are all so apparent
that no trouble should be experienced in locating and correcting
them. In reassembling the transmission the gears are meshed by
reaching through the hole left by the shifter plate. Before
replacing the shifter assembly inspect it and see that the shifter
locking pin and springs are in good condition and that the rivets
holding the shifter forks are tight.

Rear Axle:

To completely overhaul the rear axle, jack up the housing and
remove the rear wheels. This is accomplished by removing the four
bolts from the hub, then inserting two of these bolts in the
threaded holes in the rear wheel bushing. By screwing these in
evenly the wheel will be freed of the bushing. Then the bushing can
be pried from the splins of the axle shaft. In replacing the wheels
be sure and draw up on the four screws evenly until the bushing is
flush with the ends of the axle shafts. After the wheels have been
removed put the rear half of the tractor up on the transmission end
and the differential can more easily be removed. Remove the 12 cap
screws fastening each axle housing to the transmission housing and
they can be pulled off. The differential assembly can then be
lifted out. Before laying aside the axle housings, pry off with a
screw driver the steel cover that is on the outside end of each
housing. The felt grease retaining washers can then be taken out
and the outer roller bearing removed. Inspect this bearing and if
the rollers appear to be worn or crystallized or the bearing frame
is loose, replace the bearing. The bearing sleeves inside the
housing should also be looked at and if they are worn or cracked
they should be taken out and replaced. After the bearings have been
put back in, install new felt grease washers and replace the steel
cap, the edge of which must be bent into the groove in the end of
the housing and will prevent it coming off.


Remove the bolts and nuts holding the worm wheel and the
differential housings together and pull apart, exposing the spider
and differential pinions. The spider and gears, if badly worn,
should be replaced, and the differential gears on the end of the
axle shafts examined for wear and fit. If they are loose on the
axle shaft they can be replaced by forcing them down on the shaft
by an arbor press until the two-piece lock ring is exposed. This is
then removed and the gear forced off the shaft. The differential
ball bearings can be inspected for cracked or pitted balls and
replaced by forcing them from the differential case. In replacing,
care must be taken that the bearings are put back with the longer
tip of the outer ball race toward the housing. Before assembling,
inspect the axle shafts for cracks or bad wear where the outer
roller bearings ride. The worm wheel should be examined to see that
the teeth are smooth and bright the full width of the gear. If they
are worn more on one side than the other, or have a blue burnt
appearance, due to being operated without sufficient lubrication,
the ring gear then should be replaced.


The worm is removed by taking off the draw bar cap and pulling
it out. If the tractor is all assembled and the worm only is to
come out, simply push the tractor forward and it will screw out.
The worm should show a bright, smooth surface on the screw, but if
it is worn or burnt a blue color is should be replaced. The
bearings on the worm must be inspected for pitted, cracked or worn
balls and races and replaced if not in good condition. It is very
important that this bearing be in good condition, as it takes the
entire thrust of the drive. If it is necessary to remove the
bearings, one of the bushings from the rear wheels can be placed in
a vise and the splined end of the worm will fit in the splins of
the bushing and hold it, while the larger hexagon nut is removed
and the bearings can then be forced off. On some Fordsons this
thrust bearing is of the Timken type instead of a ball race, but in
either case must be carefully inspected and replaced if necessary.
In assembling replace any gaskets that are torn, shellacking them
on one side to hold them in place. Front System:

Remove the front wheels and inspect the bearings, replacing any
worn or broken ones, and while the wheels are still jacked up feel
out the play in the spindle bodies and steering connecting rod. If
this is excessive, replace the bushings and pins. The play can be
taken out of the drag link by removing the caps on the ball points
and filing off until a fit is obtained.

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