Power Steering Pump (s) and Engine PTO Ratio’s.
The power steering pump is critical to the performance of the power steering system. These power steering pumps are driven from PTO’s on truck engines and different brands and models of truck engine have different PTO rotation directions and engine speed ratio’s.
Well a power steering pump which is rotating slower or faster than it has been designed to will cause problems in the long run.
If the truck pump is running faster than required the pump will be producing excessive flow which is being returned back into the reservoir via the flow control. This will not only be wasting energy, thus fuel, it will also be heating up the power steering fluid. Power Steering systems which run hotter than designed will cause premature failure of seals and hoses as well as creating excessive wear and tear on the pump itself.
A pump which is running slower than required, will produce a lower flow. This will reduce the responsiveness of the power steering system potentially making it harder to steer.
Why would this happen.
There are a number of reasons why a power steering pump would be incorrectly driven.
The pump fitted from new could have been incorrect if a non-standard engine was fitted or because of an engine transplant to a different engine model without upgrading the power steering pump. Another reason is an incorrect replacement pump has been installed, possibly because it was available and got the truck back on the road quickly.
What ever the reason, the pump flow rate must be correctly matched to the engine and steering gear configuration to maximize the life and effectiveness of the steering system.
Common Engine PTO Ratio’s
As mentioned above different engines have different Engine PTO Ratio’s, the table below provides the ratio’s for some common engines.
These problem’s can occur with any type of pump, Eaton / Vickers pumps including V20/VTM/V10 or LUK, ZF and TRW branded pumps or any other Brand for that matter.
If in doubt give Hydrosteer a call on 1300 010 338.
We help with advice, replacement pumps or parts such as complete Bearing, Gasket, Shaft and Seal kits for V20f Vickers pumps, 32-919805BGS and much more.