Hydraulic Ram Repairs Self Inspection Guide
This article is aimed at the agricultural industry as a self help guide to farmers on inspecting their hydraulic rams to see if seals need replacing or whether the cylinder needs repairing.
As you probably are aware, a hydraulic ram is used to convert oil flow into powered linear movement, in either one direction (single-acting ram), or two directions (double-acting ram).
A double-acting ram provides powered linear movement in two opposing directions, like the ram on a shear grab for example, which uses hydraulic power to both open and close the grab.
A double acting hydraulic ram has two internal rooms, one for providing power in each direction. There are some internal seals which prevent the oil from passing from one room to the other. When these seals fail, the oil moves between the rooms, causing unwanted linear movement in the ram. This can often be seen on an attachment like a front end loader.
How to tell if you have a problem
If you leave the loader in a raised position for a period of time, it will slowly start to slide down. This is generally caused by oil escaping from one internal room to the other due to worn or damaged internal seals.
Changing the seals isn’t a difficult job once you understand a bit about the internal works of the cylinder.
What you will need to do
You will need to fully remove the ram from its working position to take it apart, so make sure of the ram is not supporting any weight or load that will suddenly move/change as you remove the connecting pins.
Health and Safety: Remember to never work under an unsupported load or object and keep safety in mind at all times and have someone working with you and conduct a quick risk assessment before you begin. Make sure you have all the right tools that you will need for the job as well to avoid accidents to yourself and to prevent damaging the cylinder.
It is also a good idea to place each component on a soft clean surface whilst removing and inspecting. This is so that you can avoid damage from surrounding debris and dirt, because although the parts can withstand high pressure, they are also easily damaged. In addition, you may wish to create a diagram of the parts so that it is easy to reassemble afterwards.
How to dismantle your hydraulic ram for inspection
- Unscrew the gland from the main body of the ram, using an appropriate tool.
- After you have unscrewed the gland fully, draw the whole rod out of the main cylinder. Any oil within the ram will flow out at this point, so have a good container ready to catch it. Be careful not to mark or scratch the polished surface of the rod. There are seals sliding on this polished surface and any scratches and flaws will quickly ruin it.
- Having drawn out the rod, inspect the internal bore of the main tube. It should be clean, smooth and clear of marks and scoring. Any marks or scoring on this inner bore will create problems with the piston seals.
- Next, unscrew the piston from the rod. Make sure the roll pin or grub screw is removed before trying to loosen the piston.
- Having unscrewed the piston, you can now slide the gland off the rod which was loosened in step 1.
- Inspect the general condition of the gland. Check the condition of the first primary O-ring and the secondary O-Ring (at the tip of the screwdriver). If it is cut or scored in any way it will need replacing.They are not expensive, so after going to the trouble of removing the cylinder it is a good idea to replace the hydraulic seals whilst it is disassembled.
- Inspect the wiper seal on top of the gland. This is a hard polyurethane seal which plays the important role of wiping the rod clean as it slides back into the ram. This prevents dirt and foreign matter entering into the ram and hydraulic system. Replace if necessary.
- Inspect the condition of the piston. It should be clean, smooth and unmarked, with undamaged faces on to which the seals are seated. Take off the piston seals and evaluate their condition and replace if necessary.
- Inspect the condition of the wear ring. There is an O-ring seated behind this wear ring so make sure that is undamaged as well. Remove the wear ring so you can full evaluate the condition of the O-ring and replace as necessary.
- Thoroughly clean and wipe down all components with a soft cloth before reassembly. This will prevent contamination into the hydraulic system and stop dirt entering in to the cylinder.
Important: Even the smallest imperfection of the seals can cause the hydraulic ram to leak oil. So be absolutely certain that there is no damage to them before reseating them. If in doubt it is always best to replace.
To reassemble the ram, simply reverse the steps. If parts need replacing, please contact us as we can supply the highest quality seals for your machinery.
After reassembling the ram, return it into its working position, connect the hydraulic hoses and you’re back in action.
If you discover that your hydraulic ram has damage to any of the components, please give us a call, as we can repair even the most badly damaged hydraulic cylinders.