Is your pipe bending machine underpressure? Don't rush to call for repairs; check these steps first.

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Is your pipe bending machine underpressure? Don't rush to call for repairs; check these steps first.

2026-05-13

If your pipe bending machine can't clamp tightly, can't bend properly, or has excessive angle rebound, it's most likely a pressure problem. Follow these steps, and you can usually fix it yourself.

Step 1: Check the fuel level – the simplest yet easiest to overlook.

If you can't see the fuel level in the fuel glass, the fuel pump is sucking in air, and the pressure won't be high enough. Fill the tank to the middle of the mark, and while you're at it, check the fuel color – whitish indicates water ingress, black indicates high-temperature contamination, both requiring an oil change.

Step 2: Listen to the fuel pump sound to determine if it's due to air ingress or wear.

A hissing, sucking sound from the fuel pump usually indicates a leak in the fuel inlet pipe or a clogged filter. Check the connections for looseness, and how long the filter has been used; replace it if necessary.

A clicking, metallic sound from the fuel pump indicates internal wear; large gaps indicate serious internal leakage, requiring pump repair or replacement.

Step 3: Check the pressure gauge and the relief valve

Turning the relief valve's adjusting handle should cause the pressure gauge needle to move, indicating the valve is working properly. Adjust it to your desired pressure. If there's no response, the valve core is stuck. Disassemble it, clean it with diesel fuel, and then reassemble.

Step 4: Check for leaks in the cylinder and piping

If the pressure builds up but drops immediately upon operation, it's likely due to a worn piston seal in the cylinder, causing high-pressure oil to leak from one side to the other—this is called internal leakage. Another possibility is a bulge in the high-pressure hose or oil seepage at the joint, resulting in obvious external leakage. Replacing the seal or the hose will solve the problem.

Step 5: Confirm motor rotation and voltage

If the motor reverses direction after installation or electrical repairs, the oil pump won't deliver pressure. Replacing two phase wires will resolve the issue. Low voltage will also weaken the motor and prevent pressure buildup; use a multimeter to check the voltage.