Sealants for steering control - a panacea or a catalyst for malfunctions?

Leaking fluid from the hydraulic power steering system is a common issue that every driver encounters at least once. In such cases, most professional mechanics recommend contacting a specialized service to check the steering system and fix the leak.

However, there are also specialists who suggest using sealing additives to eliminate leaks and extend the lifespan of all power steering components. Whom should you believe? Let's find out.

What is a Hydraulic Power Steering Sealant?

A hydraulic power steering sealant is a liquid product added to hydraulic power steering oil to stop leaks. The sealant contains substances that act on rubber components (oil seals, O-rings, and gaskets), restoring elasticity and inducing controlled expansion of the rubber. The enlarged seals (found in the repair kit of power steering pumps or other components) close gaps and seal the hydraulic power steering.

Yes, that's how power steering sealants work. But the results are not always as straightforward as promised by manufacturers and sellers of sealants.

Delayed Action: The sealant doesn't start working immediately. To stop the leak, you need to cover a distance of 50-160 km (exact distance specified in the instructions for each sealant). It requires driving with the sealant to take effect.

No Guarantee of Success: There's no certainty that the sealant will work after the first attempt. If the first try fails, manufacturers suggest doing it all over again, without recommending a professional check of the steering system to identify the cause of the leak. More is presumed to be better.

No Guarantee of Effectiveness: Importantly, there's no guarantee that the sealant will work at all. The actual cause of the hydraulic power steering leak may not be the wear of repair kit elements. Consequently, applying the sealant may not only fail to fix the leak but also introduce fluid that harms the system's components.

Cases Where Sealants Might Not Help

• Damaged Rack or Seal: If the steering rack or seal is cracked, pouring sealant won't make the leak disappear. Sealants cannot repair damaged rubber elements. Pouring more sealant won't solve the problem.
• Worn High-Pressure Hose: A worn-out high-pressure hose won't be fixed by sealant. It doesn't address the issue, and pouring more sealant will only expedite the degradation of steering system components.
• Worn Metal or Teflon Parts: Components like a cracked bushing, relief valve, or bypass tube won't be fixed by sealant; it may accelerate the degradation of these parts.
• Incompatibility with Oil: Manufacturers claim compatibility, but mixing sealant with different power steering oils might not be as trouble-free as advertised. The reality is often less rosy.

Compatibility Issues and Consequences

Impact on Oil Properties: Sealant alters the chemical structure of power steering oil, causing it to lose essential properties. This can lead to issues such as thickening, loss of viscosity, foaming, or reduced resistance to extreme temperatures.

Temporary Fix: Even if the sealant temporarily fixes a minor seal or O-ring issue, it's not a permanent solution. Sealants don't selectively target damaged parts; they act on all rubber elements, including those in good condition.

Adverse Effects on Power Steering System

• Increased Friction: Expanded rubber may block oil channels, reducing the supply to cylinder chambers. This overloads the power steering pump, possibly leading to overheating and malfunction. Turning the wheel becomes heavy, accompanied by audible noises.
• Higher Friction Between Components: Excessive friction affects wheel sensitivity during turns. Increased friction also strains the pump, resulting in noise.
• Interference with Moving Parts: Overexpanded seals may hinder the movement of steering system components, worsening control and causing difficulties while driving.

Conclusion

Using sealants as a solution for power steering leaks is not foolproof. It may temporarily address minor issues but can lead to long-term damage and increased repair costs. If you suspect a power steering leak, consulting a professional mechanic for a thorough inspection and targeted repair is the wisest course of action. Sealants are not a universal remedy, and their consequences on the power steering system can be detrimental.