Why Does My Log Splitter Bogs Down Under Pressure?

What can be worse than discovering that the machinery you require to meet an urgent commitment slows down at an even lumbering pace? Not an ideal situation. Agree? 

Now imagine during a cold winter night, you reach out to your log splitter to get through some firewood and you are disheartened to find out that the log splitter stalls under load. By and large, log splitters are simple machines used to slice the wood into smaller pieces, not often does a log splitter face any problem in functioning. 

In case a log splitter stalls under load check for the model of log splitter, that way it is easier to reach out to the root cause. Simpler the design of a log splitter is, easier to find out the exact reason!

Before digging deeper, let’s take a quick look at the possible reasons to this problem – Why does my log splitter bogs down under pressure?

  • The log is not kept properly.
  • The log is either too big or too hard exceeding the splitter’s capacity.
  • The cutting edge of wedge might be blunt.
  • The adjustments of the screw that controls maximum pressure might be unauthorized.
  • There can be a partial blockage in oil-ways in the pump and endplates.
  • The operating lever may be loose or not bent at 90 degrees to the mounting side thus the valve cannot operate correctly.
  • The presence of silicon sealant or any other contaminant in the tank can also be a deterrent. 

Most of the issues can be sorted on your own if you have functional knowledge of log splitter’s working. If the log splitter is failing under pressure and stalls out, there are chances that the system is not working in accordance with the size of the hydraulic pump and its capabilities. 

A hydraulic pump is used to control and regulate the flow of hydraulic fluid to the cylinder to create pressure; this pressure helps the wedge to split the logs. Well, hydraulic issues are very common but equally easy to identify and mend. Let us guide you through a few steps that can help you in troubleshooting.

First and foremost, pin down the observations that are occurring. It might be possible that the logs you want to split are too large or maybe too green. Such logs expect greater force than what your splitter is capable of handling, hence it is recommended to check the capacity of the hydraulic pump. If this is not the case, check for the motor fan if it is spinning effortlessly. If you observe any glitch in spin, it may have a blockage.

If that is also not the case, ensure that no physical part of the machine such as a handle or other is loose. It will prevent the lever from pushing down completely. Similarly, make sure the splitter is pointing upwards to distribute the power equally since it will create stress on the machine if faced downhill. 

Make sure the coupler or a connector that joins the hydraulic pump and the motor is not damaged. The coupler consists of three parts viz. one shaft connecting the motor upwards (motor shaft), the other shaft facing the pump down (pump shaft) and between both the shafts there is a rubber spider gear. However, if any part of the coupler is broken, it can easily be replaced and it would also not cause a hole in your pocket. 

Besides this, there is a possibility that some air is trapped inside the machine that affects the power. Bleeding your log splitter is a possible solution for the same. Just rotate clockwise the oil-filling plug and remove the plug. Now release the ram and put back the oil-filling plug. This will remove all the excess air trapped inside the splitter.

If still your log splitter shuts off under load, most likely your hydraulic pump is jammed or stuck in its high flow/low-pressure stage (described as the first stage). In this stage, the pump produces about 400-900psi which is far less than its rated GPM. 

An automatic process is carried out for transition from the first stage to the second stage i.e. from high flow/low pressure to low flow/high-pressure stage, achieved through internal valving inside the hydraulic pump. 

Try and check if revolving the valve to almost 2 turns helps in achieving the required GPM. If the valving is posing some malfunction, it is recommended to replace the whole pump which is a more economical option.

There are also high chances that the cylinder piston has been poorly sealed down which causes a log splitter to stall under load. Unless it has no severe internal damages, rebuilding a cylinder is a more cost-effective option. 


On the whole, the most common causes of log splitter bogging down under load are related to either hydraulics or engine maintenance. Generally, the issues are simple and can be fixed easily on your own. Still, if the problem persists you can always resort to the replacement of parts.