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Friday, October 26, 2018

Warning turn of the PTO Power Take Off before driving away to avoid Catastrophic Pump Damage


One of the most common failures we come across after hydraulic hose bursting or being damaged is the hydraulic pump which is part of the PTO on mobile hydraulic machinery.

What is a PTO? Power Take Of (Unit) is a specially designed gearbox that bolts to a Truck's Gear Gearbox or Transmission. They are used to drive Hydraulic Gear or Piston Pumps and to provide Fluid power to Mobile or Truck Mounted Hydraulic Systems such as those found in:

  • Compactors, 
  • Mobile Cranes, 
  • Walking Floors, 
  • Tilt Trays, 
  • Tow Trucks, 
  • Tippers, 
  • Low Loaders, 
  • Container Loaders, 
  • Winches, 
  • Skip Bin Trucks and
  • Concrete Agitators.

Most PTO Systems are designed to be engaged and operated whilst the vehicle is stationary and running at low to medium low engine speeds.

Click here to talk to one of our team about a new or replacement PTO System

So what happens when you forget to switch off the PTO and decide to drive off to the next destination? Over speed, Cavitation, Heat, Noise = Massive Wear and or eventual Catastrophic Failure.

Another Failed Idler Gear removed from a Damaged gear pump out of a Skip Bin Truck, the owner of this truck was wondering why the hydraulic pump could not generate enough power to lift bins on and off the truck.
In the example below the PTO was driving a pump for a tipper application the driver may have heard the additional noise and should have felt a great reluctance for the transmission to change gears.

The Picture shows such a failure probably caused by a combination of over speed, cavitation,  heat and sometimes lack of lubrication because correct oil level has not being maintained.

In the picture below The PTO is on the Right and Gear Pump is on the left.
Cavitation is the rapid formation and violent collapse of vapor pockets in a flowing liquid caused by areas or regions of very low pressure (read vacuum). Cavitation can and will cause Structural and Errosive damage.

Damaged power take off  gearbox and Hydraulic Gear pump caused by over speed when driver forgot to disengage the PTO gear box from the main transmission. Gear pump input shaft has sheared off in PTO out put shaft when gear teeth broke off  prevented further rotation.  

Cavitation damage can also be found in other types of liquid pumps as well as boat propellers.

In this example, running the PTO at High Speed caused the pump to Cavitate, Over Heat and rapidly Wear and Errode and eventually caused a hardened tooth to break off one of the gears. Being a solid the broken tooth jammed the rest of the gear pump and caused the whole pump to almost instantly stop. Because the PTO was still engaged and driving the pump the input shaft of the pump then sheared off in the PTO's Output shaft.

A failure like this will also require that the whole hydraulic system including hoses, pipes, cylinders, tank and suction strainer be flushed cleaned and all hydraulic oil and filters be replaced.

To Buy Online

  • Replacement PTO Pumps, 
  • Suction & Return Filters, 
  • Flow Control Valves,
  • Pressure Test Kits
  • Hydraulic Hose  
  • Remote Control Systems, 
  • D.I.Y Medium Pressure Hydraulic Hose Fittings to 270 Bar (4000 PSI) 
  • Custom Made High Pressure Hose Assemblies. To 410 Bar (6,000 PSI)
  • Click Here