Hand Pallet Truck Repair

FIRST, SOME QUESTIONS

• Are you feeling confident, dismantling; removing seals; procuring seals; re-assembling?
• Do you have all the necessary tools, or are you happy to procure them?

THINGS YOU WILL NEED

• Degreasing liquid.
• Set of winkle pickers – seal removal spikes with different end shapes.
• Hammer.
• Set of pin punches. Longer the better. Best quality is worth it.
• Hydraulic fluid.
• Hydraulic grease.
• Rags and Containers (to hold parts / drain fluid into).
• Shifters in different sizes.
• Metric Allen key set.
• Screwdrivers – various sizes.
• Long nosed pliers.
• Circlip pliers.
• Other. Dependent upon make and model of truck.

FIRST

I always start with a good degreaser. We make our own – King Machinery Degreaser. It can be used alone by simply spraying on then wiping off – great for when there is no water available, or if you clean, inspect and repair hydraulic lifters as we do through our subsidiary The Equipment Inspector, where we cannot get the lifters wet.

If preferred, leave the degreaser on for 5 minutes, agitate and grease or dirt with a long brush, then hose off.

When the equipment is thoroughly clean and dry, look for leaks. Test the lifter under a heavy load. You can then choose to just repair the obvious leak, or do as we do, which is to remove all the seals and replace them. The reason being, is that you don’t know when another seal will give way, especially if the pallet truck is old.

There are three main seal areas to consider. Main piston, pump piston and down control piston.

HANDLE REMOVAL

Before removing the handle from the frame, be aware that the chain that links the lever in the top of the handle goes through the handle pivot pin at the bottom, so you need firstly to lift the down pivot fork, using a thin screwdriver from the outside, to release the screw with a nut on it from the fork, then pull the chain, screw and nut through the hole in the pivot pin.

It is at this point, that you need to observe how the pump piston is retained, as it is sprung. On this model, it came with a piston retaining pin. Pull the handle down to tension the spring, then slide a pin in the two holes provided. When you bring the handle back up, the spring cap with the spring underneath it, will have been captured, and you can then knock out the pivot pin retainers, then using a large diameter pin punch, knock out the pin. Be careful not to burr the outside edge, or it will be difficult to put back in.

Using a large screwdriver as a lever placed over the spring cap, the spring retaining pin can be removed and the spring will rise slightly, allowing access to the pump piston.

MAIN PISTON SEALS REMOVAL AND FITTING

 At this point, I would place the pallet truck onto the forklift, across the tines, with the rear wheels dangling down.

Undo the screw holding the top of the piston to the top of the frame. The screw goes into a groove that allows the piston to rotate but secures the piston to the frame.

The piston will just pull out of the frame. Be careful, there is a ball bearing sitting in the top of the piston. Clean it, and place it into the parts container. The rear wheels and housing will fall slightly.

Clean the piston and place it into the parts container. Hydraulic fluid may come out of the housing.

Inside the housing you will find seal/s and O rings. Remove them carefully using the winkle pickers.

PUMP PISTON

Pull the pump piston out of the housing, along with the spring and spring cap. Some caps may be retained by a circlip or a roll pin. Hydraulic fluid may flow out of the housing, so place a clean dry container underneath. Clean the parts removed, and place them in the parts container.

Some pistons may have seal/s and O rings on the shaft. Remove them with your winkle pickers, taking much care to ensure the point of the removing tool is not scoring the internal piston seal surface.

Some pistons may be sealed using seal/s, O rings and a wiper seal embedded into the housing itself.

If you feel unsure about how they will be re-assembled, draw each part, showing which way up the seal is.

DOWN CONTROL PISTON

Similar to the other pistons. Check that you haven’t missed any O rings on the inside of the shaft.

RE-ASSEMBLY

Obtain all the seals, O rings and any replacement parts from the supplier. Note: If not sourcing original parts, take as many of the parts with you for measuring confirmation purposes.

If you have been paying attention during the dis-assembly, or taking notes, you will have no trouble re-assembling all the parts.

Remember that cup seals face down, whilst the lip on the wiper seal faces up.

A word of warning. Some seals are placed way down inside the wall of the housing. It can be tricky to push them down, then fit them into the groove provided. The seal has often to be twisted in order to get it down to where it can be expanded into the groove. Hydraulic grease helps

Plastic washer / spacers are often used in order to fill up the gap between the groove and the seal. They are cut on an angle, in order to be able to remove and re-fit them. You must ensure that the overlap is correct and that the spacer is flat during re-fitting.

Two important points:

• After fitting the pump piston, spring and spring cap assembly, use a long screwdriver to force it down into the housing, then re-fit the retaining pin through the two holes. This will allow you to fit the handle easily. When fitted, remove the retaining pin.
• After you have knocked the pivot pin in, then secured it with the roll pins, thread the chain with the nut on it, through the hole in the pivot pin and tuck it under the down control pivot fork. Failure to do so, will have you scratching you head as to why it won’t work after being repaired.

IMPORTANT NOTES 

• All tools, components housings must be clean and free of water at all times.
• Use fresh hydraulic oil of the correct viscosity to re-fill the reservoir after servicing.
• The use of hydraulic grease on all sliding parts is necessary during re-assembly.
• It is imperative that you obtain the correct seal kit for the model being repaired, or that you have been supplied like for like (or better) by a reputable seal supplier.
• Not all systems are the same, but the principles remain the same. Some cheaper trucks come with poor or no plating on the pistons. Some have seals that are unique to that brand. Sometimes it is cheaper to scrap the truck, as they are no longer an expensive commodity, but in today’s environment, anything you can do to help save the planet must be a good thing.

Ron Mileham.

Pack King. www.packking.com.au