How To Repair 8n Ford Tractor Hydraulic Lift

Question:

"My hydraulic lift isn't working correct."

Answer:

The 8N hydraulic system is simple yet elegant and works cracking when properly adapted and maintained. It consists of a pto driven piston blazon pump with internal control valves and a lift cylinder connected to the rear lift arms. The command lever and quadrant moves the valve spools on the pump to command the elevator. The most mutual complaints are addressed below. The general data provided below is no substitute for a repair manual. If you lot need to work on the hydraulic organisation, it'southward highly recommended that you lot first buy the I&T FO-4 shop transmission and follow the instructions at that place for repairs and adjustments. It's also highly recommended that you change the hydraulic oil (gear oil) and go along it fresh and clean at all times. The oil sump holds 5 gallons that is shared with the transmission and rear end of the tractor. It has a trend to accumulate moisture from condensation inside the gear cases and the h2o collects in the bottom of the sump where it is fatigued directly into the hydraulic pump. In cold climates the water can freeze and break the chambers in the pump. You definitely don't want that to happen. If the oil looks milky, it'southward got water in it. Change it.

Question:

"My elevator isn't working at all."

Respond:

If the lift won't heighten at all, commencement make sure the pto is engaged and the pto shaft is turning as information technology should be. Brand sure the oil level isn't low. If those ii things check out ok plough off the engine and remove the right side access cover (the one with the dipstick) and slide your hand downwards along the command rod into the oil and feel the cease of the rod where information technology goes into the control valve pin. Make sure the rod is connected and that it is moving the control valve spools in and out equally yous move the lift control lever up and downward. Other possibilities are a defective relief valve or a ruptured oil tube that goes from the pump base of operations to the superlative cover. To check these, leave the side cover off and start the tractor. Have a fairly heavy weight or load on the lift arms. Raise the lift control lever and scout inside the crenel for oil spraying out in the area of the relief valve or from the side of the cavity where the tube is located. If no oil is spraying out anywhere, you could have a bad pump. Check the pump force per unit area as outlined in the I&T FO-4 manual.

Question:

"My lift only comes upward half way and so stops."

Answer:

This is a very common complaint and tin almost e'er exist attributed to a worn cam follower pin in the lift control linkage. Loosen the 4 bolts holding the quadrant command lever bracket to the top cover. Slide the quadrant bracket toward the rear of the tractor (bolt holes are elongated). If the quadrant subclass is all the way back and the lift notwithstanding doesn't come all the way upwardly, you'll have to replace the worn cam follower pin. Remove the top cover and place it bottom side up on the workbench.

Cam follower pin location

A badly worn pin

Detect the worn pin. Disassemble the control linkage until you lot tin can get the part with the worn pivot out of there. Press or drive the worn pin out. Supercede with the correct hardened dowel pin part number 374072S from Ford/New Holland. This is listed equally a v/16″ x 7/eight″ dowel pivot but it is really .309″ diameter non five/16″ (.3125″). Pressing or driving a mutual .3125″ pin into the .309″ hole tin can crusade major problems and I strongly advise confronting it (Some thrifty folks rotate the one-time pin 180 degrees and reinstall it to get another few years of wearable out of it. That usually works ok if you can't spare the two bucks for a new one). Reassemble the linkage and adjust equally per the shop manual instructions. Many times you volition find that simply replacing the worn pin volition take care of the problem without whatever further adjustments, but you have to completely reassemble the tractor to find out if you are lucky or not. Before replacing the meridian cover, take the time to inspect everything else in at that place for wear or other issues. This is an fantabulous time to rebuild the lift cylinder also. See the adjacent question.

Question:

"My lift drifts down when the pto stops."

Answer:

Leakdown is probably the virtually common complaint with the Due north tractors, but it'due south usually piece of cake to set up. If you have an implement on the lift and it drifts downward over a few minutes fourth dimension after the tractor is close off you lot take some leakage. If the implement drops as shortly as you push the clutch pedal in, you have major leakage. In some cases the relief valve can leak and crusade this problem, only if the relief valve is leaky it usually also shows up as a weak lift (won't lift a heavy load or implement). The control valve spools in the pump base can leak due to scoring in the bores simply this is rare and generally non repairable except by a major pump rebuild. The most common cause of leakdown is worn lift cylinder piston rings. You can determine if the leakage is coming from the elevator cylinder by removing the right side encompass (the one with the dipstick) and starting the tractor. Accept a fairly heavy weight or load on the lift arms. Heighten the lift control lever and watch inside the crenel for oil leaking out from above in the area of the lift cylinder. If the cylinder is leaking, y'all will run into it. If the relief valve is leaking y'all will see the oil bubbling up from the pump expanse. The N tractors originally had a piston with 3 cast iron rings to seal it. These rings are even so bachelor, inexpensive and will piece of work just fine, but a small amount of leakdown is normal and is to be expected with them. With the NAA tractors Ford switched to a piston with a neoprene rubber o-ring and leather fill-in ring that tin exist used in the older Northward serial tractors. This provides a much more positive seal to eliminate the small leakage from the cast iron rings. The NAA piston and seal will price more to replace than only buying new cast iron rings. The determining factor in which way to become is the condition of the cylinder bore. Remove the lift cover and remove the 4 bolts property the cylinder to the comprehend. You tin remove the piston fron the cylinder by applying a footling compressed air to the oil inlet hole in the cylinder. Don't use a loftier pressure or you'll blast the piston out of at that place like a rocket. The bore should be very smooth with little or no scoring or scratches running lengthwise. Information technology can (and probably should) be lightly honed to a cleanup. If the scratches are deep, they will permit some oil to leak down the grooves past the cast atomic number 26 rings. In this case the NAA seal will work meliorate, merely only for a brusk time. The scratches or grooves volition chew into the new neoprene seal and it will leak worse than ever. If you have deep scratches and do not want to spend the coin to supervene upon the entire cylinder associates you should employ the cast atomic number 26 rings and live with the small leakage. If the cylinder bore is in practiced shape or has simply very faint scratches or grooves use the NAA piston and seal.

Question:

"My lift went upwardly only now it won't become down."

Answer:

This is nearly e'er caused by the control valve spools in the pump base getting stuck in the bore, most probable due to water or clay in the oil. Turn off the engine and remove the right side access cover (the i with the dipstick) and slide your paw down along the control rod into the oil and feel the end of the rod where it goes into the control valve pivot. Brand sure the rod is connected and that it is moving the control valve spools in and out every bit you move the lift control lever upwards and downward. Chances are, you volition find that the valve pivot is stuck and not moving. Y'all may be able to become it to interruption free past prying lightly on it with a screwdriver between the pivot caput (ball socket) and the pump base. When it breaks free and starts working again, CHANGE THE OIL. If it'southward really stuck tight, yous'll take to pull the pump and rebuild it.

Question:

"My lift works by itself but not with a heavy load on it."

Answer:

This could exist astringent leakage at the cylinder, a bad relief valve, or a badly worn pump. Check for elevator cylinder leakage and for relief valve leakage as described in the questions to a higher place. If no major leakage is noted, so cheque the pump pressure as outlined in the FO-4 manual. A rebuild is probably in club.

Question:

"My hydraulic pump makes knocking noises under load."

Answer:

What yous're hearing is the sound of cams/pistons in the pump banging together. When the pump is new you get a slight knocking as the lift reaches the set height. That'south normal in all of them because the pump closes off the inlet port when it stops and the pump cavitates as it starves for oil. Only every bit the cams habiliment they begin to knock louder as they actuate the pistons from side to side in the pump. The louder the knock, the more wear your pump has on information technology. It's generally not an immediate pressing problem. If the knock is faint you lot can probably put off repairs for quite a while. If information technology'due south knocking loudly yous should buy a pump repair kit and practise a rebuild before it quits all together. Leaky or sticking valves in the side chambers will as well make the pump knock loudly.

Question:

"My lift is very jerky and erratic when raising."

Answer:

This is usually a sign of a defective or sticking valve in the pump. The pump piston pushes the oil out then pulls information technology dorsum in as it returns. Time for a pump rebuild.