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 expenditure.
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 permit.
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 flushed.
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 handled.
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.
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 started.
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 finished.
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 block.
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 released.
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 holes.
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.
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.