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Doug Byam 

I purchased my ARK System 9000 Loader (Simplicity Product #1690157) in semi-basket case condition. I had a lot to learn about loaders and very little experience with hydraulic systems. Fortunately I didn’t mount the loader on the tractor to find out if it worked OK. I decided to paint it and go through the components first in fear that it would leak all over the place and I would then have to go through the agony of removing it for repairs. 

If you already have a loader on your tractor you know where the kinks are located and perhaps you will find something in this bulletin that will help you straighten them out. 

I purchased the Operator’s Manual from Simplicity Publications and it’s an OK Parts Manual but little else. The photos are too fuzzy to be of much use and the operator’s instructions are very brief. No trouble shooting is included. 

Click for a closer view


Before you remove anything it is important to mark certain components to assist in re-assembly. Of primary concern are the hoses that connect the steel lines to the control valve. In my case I disconnected the rubber hoses from the steel lines leaving them attached to the control valve. This worked out well except I didn’t mark them. I never detached the steel lines from the tees, I just straightened the lines and painted them while fastened to the tees. 

There are two types of cylinders Lift and Tilt, identify each end as Rod (where the rod sticks out) or Piston, this covers all four lines. I suggest the lines be marked, using masking tape flags or any other method you prefer, with a code that shows Lift (L) or Tilt (T) end of the cylinder, Rod (R) or Piston (P) and the valve port letter. I marked them thus: 

Lift Rod, Port A:        LRA 

Lift Piston, Port B:            LPB 

Tilt Piston, Port C:            TPC 

Tilt Rod, Port D:        TRD 

Actually as long as you have this chart of codes you really don’t need to mark anything. Just be sure you familiarize your self with the orientation of the steel line ends where they attach to the rubber hoses on the right side of the loader. Each of these lines is bent a little different at the end so that they don’t interfere with each other. If you have a damaged line you should be able to replace it by purchasing one from a local hydraulics distributor. It is standard ¼” ID steel tubing with a JIC flange joint on each end. The system is designed with 1250# of pressure so you don’t need any exotic materials. You can bend the line yourself if you have a small hand tubing bender using the old line for a pattern. 

If you have the loader mounted on the tractor you should pump out the reservoir first before removing any other fittings. Detach the Supply Line from the Control Valve and direct it into a five-gallon bucket. You may want to cut a cardboard cover to reduce splashing. Run the pump until the reservoir is dry and no more oil comes out. You can then disconnect the large suction line from the base of the upright with minimum loss of oil to the floor. 

It’s almost impossible to remove the cylinder lines without dripping some oil. Fortunately there isn’t much oil in them. I put a large sheet of cardboard over the floor and have a lot of Kitty Litter or Oil Dry handy. 

I don’t recommend purging the cylinders while they are attached to the loader. It’s an invitation to an oil batch. We will cover this in the next section. For the time being unhook them and lay them on cardboard, some oil will come out but most will stay in the cylinder. 


If you had the loader mounted and used it you will know if you have a leaking cylinder. Before you hustle it to a repair shop read on and check out all the cylinders before making your move. 

Most cylinder problems are caused by bent piston rods. Usually they become bent from overloading. This caused the rod to drag on the internal guide that is behind the oil seal. This wears the guide and the side of the rod where it is dragging. When enough material is worn away the seal won’t hold the oil in the piston causing leaks. Wear can also occur from dirt scuffing the rod at the seal area. 

To check the cylinders further you must remove the oil from them and then check for free movement. Since the piston should already be retracted you will need to force the cylinder into the extended position. Do this with air pressure. Slip a length of air hose over the fitting on the rod end and place the other end in a bucket, making sure the hose can fly out of the bucket when you pressurize the piston end. Use a blowgun and pressurize the piston end fitting carefully. If the cylinder is in good condition the oil will be driven out and the rod extended with 25-30# of air. If the rod is bent it is likely you will not be able to move the piston with 100-125# of air. 

Once the oil is removed you should be able to freely move the rod in and out by hand. If the rod is bent take the cylinder to a hydraulic cylinder repair shop. They will either straighten the rod or install a new one. They will also install and new guide and seals. The cost varies but mine cost about $65 each to overhaul. 

Check the rod and cylinder ends for slop where the Clevis Pins go through the bushings. If these are worn badly buy new bushings, drill a hole for the grease to go though and press them into the eyes. It is not important to have a perfect snug fit on these pins unless you plan to use this loader eight hours a day every day. If it is for casual use you can stand a lot of slop. 


My loader had been used hard for 25 years or so cleaning chicken barns. Moving all this chicken poop exposed the weak points in the loader. The Under Frame had been broken, where the uprights attach, several times. I had to grind it out and re-weld it before painting it as it leaked oil at the bottom of the reservoir. Needless to say the welds looked a lot like the product they had been loading all the years. 

In many cases the Upright Braces, which are made of flattened tubing, are bent. Straighten them out as best you can. Replace any undersized or worn bolts. 

The Lift Arm assembly had been completely broken off at the top of the large front cross brace. The lift arms were fish plated with a diamond shaped plate and an additional brace was installed on both sides from the cylinder end of the lift cylinder to a point just outboard of the break. 

Two of the cylinder rods were badly bent, likely when the lift arms broke. 

The Bucket Guide Rod and Tube were completely gone but easily fabricated.  

It is very easy to find existing cracks in the components if you first sand blast them. This may seem a little extreme but if you want a strong loader with a nice restoration I recommend the blasting first. 


Loaders of this age that have had a long working life usually have a replacement pump installed. Mine had a very large pump and I am replacing it with a smaller one for several reasons. You can check the displacement of your pump by disconnecting the pressure line from the control valve, arranging a small jar to catch the fluid, and revolving the pump pulley one revolution by hand. Mine displaced 1.26 cubic inches or .7 oz of oil per revolution. This amount times 1800 rpm equals 9.8 gpm. This speed is not much more than an idle on this tractor!  

Part of the problem lies in the size of the PTO pulley built into the Pow’rMax. It is 6.5” in diameter and because of an interference problem with the suspension pivot bolt the pump drive pulley must be smaller than the drive pulley resulting in a “speed-up” condition. Consequently at 2500 RPM where we operate the engine the pump is running at 3000 rpm and my pump puts out over 15 gpm. I have extended the drop arms, on my pump mounting bracket, one inch and the largest pulley I can use on the pump is 6.5”, a one to one ratio. 

Pow’rMax Paul has calculated the size pump required for normal use on this loader and he recommends 3-4 gpm at working rpm which gives 6-8 seconds lift time. It appears that a pump that displaces .4 to .56 cubic inch per rpm is ideally suited to this loader. Too large a pump is very hard on the drive belt and heats up the hydraulic fluid rapidly. If you buy a new pump be sure you get one that is designed to run “Clock-Wise” rotation. A counter clock-wise pump will pull oil from the pressure side and expel it into the reservoir resulting in a Loader that will not work. 

I replaced the large pump on my tractor with a Fenner Series E pump, it has a displacement of .384 cubic inches per revolution. It pumps 4.3 gallons per minute at 3200 rpm. The loader works smoothly and it puts much less load on the engine when I engage the front clutch. 

To select the correct belt run a tape measure around the two pulleys with the belt tensioner fully raised. Be sure to use a 5L or B Section belt as a 4L or A Section is likely to stretch rapidly. 

Please feel free to copy this material and distribute it to others if you choose. If you have any questions mail me at dbyam@tds.net










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