• Hydraulic Systems Mgr

What's wrong with my wrench? - Troubleshooting topics with hydraulic torque wrenches

Just like every other hydraulic tool or ram, if a wrench is leaking and losing oil when your pump is on, then you probably have a blown o-ring. The only cure for that is to open the wrench up and to replace whatever broken seals and o-rings you find there. However, there can be other situations where a wrench is not actively leaking, but it is also not operating correctly. Below we have listed out some of the common issues we find, which aren’t leaks, but which keep the wrench from working the way it should.

Pressure at the pump but no movement - Since the wrench, the pump and the hoses probably all have quick connects (QD’s) they can be a common source of problems. If the quick connects are not made up properly, you will always have issues with the operation of the wrench. An easy way to spot this situation is if the pump goes up to full pressure quickly but the wrench does not move. In this situation the oil is running into a QD which is not letting the oil pass through and preventing the action of the wrench.

Wrench piston extending when the pump is not being actuated - If you are working with a wrench which actuates (extends) when the pump is idling, then your fittings are probably backwards. In this case the wrench should retract when you actuate the pump. This can also happen if you are combining two hoses end-to-end. The solution here is obvious that you should inspect your setup and trace the advance and return lines. You will probably need to swap your fittings. In the case of the hoses, it may be easier to just use an odd number of hoses (use 3 hoses instead of 2).

Wrench actuates but the hex head has no power or slips - This situation is a bit more unusual but the good news is that it is easy to spot and should be easy to fix. In a situation where the wrench is actuating, but the hex head is slipping, you may find that the Drive Segment has been installed backwards(pictured). If this is the case then it is as simple as disassembling the wrench head and re-installing the drive segment correctly.

Wrench is not actuating - If you are working with a wrench and it is simply not operating when the pump is actuated then the issue may be with the pump or hose instead of the wrench. Unlike the situation with the quick connects, where the pressure quickly spiked, you may find in this case that the pump is just not providing pressure for some reason. The other reason this might happen is if you are asking the wrench to do more than it actually can. For example, we can see this if there is any confusion about converting pressure to torque. The wrench stalls as it just isn’t strong enough to budge the nut it is on.

Wrench pressures up but doesn’t leak or the piston only extends partially - In this situation you may be facing something more than just a simple fix. When we see this sort of response from a wrench it can mean that there is a damaged spot on the piston or cylinder surface. Meaning that, the piston extends as the pressure builds behind it, but at some point along its path it encounters an area where the oil bypasses the seal and goes around it. It is leaking internally and you might have heard this called “bypassin”.

If you run into one of these or if you have questions about something not covered here, please call us and we can discuss.

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