Orbital Valve Steering Problems – Troubleshooting and Preventing Issues

The orbital steering valve is among the most critical components in the vehicle/machinery steering system. It is designed to transmit and increase the steering wheel force to the transmission mechanism that changes the direction of movement of the vehicle or machinery. Through the orbital valve, the driver can realize a reliable, safe, flexible, and massive steering force control from his minimal operational input. 

Today, we shall discuss the operations of the orbital steering valve with emphasis on issues that may arise and prevent its proper operation. Further, the article will explore various troubleshooting techniques and highlight methods that could prevent these problems from occurring.

Overview

Orbital steering valves are precision flow valves that direct or steer pressurized fluids in a particular system. The orbital valves operate without the normal rubber tubing seals which are prone to constant failures. Orbital steering valves are directional hydraulic control valves that use a tilt-and-turn process of operation. The orbital valve is mainly applied in steering systems of vehicles, agricultural machinery, road construction machinery, and a host of other applications.

The absence of rubber seals enables the orbital valve to have an easy-to-use, reliable, and long-term performance. They have strong metal-like seals to enhance their performance in difficult situations. Apart from their use in vehicles and machinery, they are also best suited in suction isolation, flow lines, dryer switching, and emergency shutdowns among other functions in the gas, petrochemical, pharmaceutical, and oil industries.

How it works

• The orbital valve operates in a tilt-and-turn switch system for opening and closing.
• When the valve core sticks to the seat it shuts off the flow, while when the core tilts away from the seat, it allows a uniform flow through the line.
• Afterwards, the core turns from its seat to complete the process.
• The absence of rubber seals for the opening and closing processes reduces localized fluid pressure which would create uneven wear in the conventional valves.
• When turned, the valve core and stem make a 900 turn through precision grooves and fixed guide pins without touching the seat.
• Further rotation pushes the stem down which presses the core against the seat to shut out fluid flow.

This operational mode eliminates abrasion between the moving parts that usually causes wearing in the conventional valves. These parts are made of polished hardcore materials that work in tough conditions without the risk of losing the seal integrity common in conventional valves.

The orbital valve in the steering systems uses a dual stem guide technique with hard stem slots alongside strong guide pins that control the lift and tilt valve movement. The dual system enables the valve to switch between left and right to direct the steering force which makes the vehicle turn in the intended direction.

Symptoms of Failure

There are various types of orbital valves which include manual, electric, hydraulic, and pneumatic. All types of orbital valves are designed for performance with minimal maintenance requirements and are expected to last for a long. However, due to the environment in which they operate, they are prone to total or intermittent failures.

There are tell-tale signs that can give you a hint that your orbital valve has a fault. The following are some of the symptoms that tell you your valve is failing

• Leaking fluid

A faulty valve will leak steering fluid underneath your car. The steering fluid can either be clear or amber with a marshmallow smell and is highly flammable. You can place a screen/mat underneath your vehicle when parked overnight to check for any leakages.

• Whining Noise

You may get a whining noise when turning or when the engine is idle

• Difficulties in Steering

If you find it hard to turn a corner with your vehicle or machinery, there is a possibility that the orbital valve is not directing the fluid correctly as required. This reduces the fluid pressure thus compromising the ability of the steering unit to turn your vehicle. 

It is advisable that you always listen to any noises when turning, watch out for any stiffness/difficulty when turning around, and make regular checks for any fluid leaks below your car. These actions will go a long way in identifying orbital valve problems early enough.

Orbital Valve Problems

The orbital valve is likely to have the following problems

1) Structural breakage

The handle, the stem, or the end connector can become broken. This could be due to external impacts, misalignment, or frozen movements. To rectify this, ensure you diagnose the source of the problem and have it rectified.

2) Broken Valve Body

This can result from system misalignment, excess internal pressure, or chemical attack on the valve. Ensure the system is aligned properly, use the recommended internal pressure rating, and that non-compatible chemicals are not allowed through the valve.

3) Internal Leakage

Leakages may come as a result of thermal damage that arises due to excessive operating temperatures and external heat that may distort the orbital valve. Ensure the valve operates within the recommended temperature range.

4) Excess/Low fluid pressure

If the fluid pressure is too high, it will destroy the system while if it is too low, it will not be able to perform as per the expectations. High pressure and high flows lead to great heat generation in the system. Such heat leads to pressure spikes, uncontrolled fluid flow, and problems that damage the valve and by extension the steering system.

5) Steering not returning to the center

This may be due to a faulty Load reactive lever in the orbital valve.

6) Steering that pulls or drifts

The steering wheel may pull away or drift from the intended direction

7) The steering wheel of the center

When on a straight alignment, the steering wheel tilts away from the normal central position.

Troubleshooting

Most failures of the orbital steering valve can be diagnosed through testing and isolating various sections of the entire steering system. However, it is important to have the requisite knowledge of interpreting the test results.

When troubleshooting for orbital valve faults, always ensure you follow a logical and systematic order to be able to pinpoint the exact problem. Check and confirm the answers to some simple common questions such as:

• What is the fluid level of the pump when in operation?
• What is the condition of the fluid?
• At what pressure and direction is the fluid flowing?
• What is the fluid temperature?
• Are there any abnormal vibrations or noises being experienced?
• Is there any evidence of fluid leakage?

This and many other questions will go a big way in helping to determine the possible faults that may be crippling the steering of your machine.

Preventing the Problems

Though orbital valves are made to last, the above-mentioned problems could be largely avoided with routine checks and maintenance. Lubrication is one key routine that extends the valve life. Manufacturers recommend planned maintenance for orbital valves depending on their applications. One of the major causes of orbital valve failure is excess pressure and high temperature. 

To avoid pressure failures in your valve, carry out the pressure test as regularly as possible.

1) Steering Pressure Test

It is used to test the steering system's fluid pressure, pump, pressure lines the relief valve, and the control valve. Before carrying out the test, check for any visible external leaks as well as fluid levels in the system. Also, confirm whether any strange noises are coming through when you open or close the valve.

Procedure:

• Stop the engine and connect the pressure tester. Put the shut-off valve in the 'open' position.
• Start the engine and let it run. Turn the steering wheel several times right and left to raise the fluid to its operating temperature and also to release any trapped air.
• Connect the test gauge and close the shut-off valve for five seconds. Check the gauge reading and compare it with the manufacturer's recommended reading/specifications.
• Ensure you do not keep the valve closed for more than five seconds as this would cause the fluid to overheat and damage the pump,
• Put the shut-off valve in the open position and check for leaks in the gear housing. To do this, turn and hold the steering wheel to its end and note the fluid pressure reading on the gauge against the recommended reading. Release the steering wheel immediately to avoid damaging the pump. If the pressure is too low, you may have internal leaks.
• To check for faulty flow, record the gauge reading with the engine running at 1000 and 3000 RPM. Compare your reading with the recommendations and if they fall out of specifications, there is a fault in the fluid flow.

2) Orbital Valve Servicing

• The orbital valve should be serviced every 500 cycles when used in severe situations and corrosive environments.
• If the valve is used more than ten times a day, servicing should be done after every 1000 cycles.
• When the valve is operated once per day, lubrication should be done every three months.
• The valve should have a yearly service regardless of usage.

With these pressure tests and routine maintenance and servicing, the orbital steering valve will have an extended life span.