A Customer Concern

When a service dealer called his CARDONE sales representative with a concern about his 20-25% steering warranty rate, CARDONE's quality team contacted him to learn more and find the root cause.

They learned that the technician uses a reliable, national brand of power steering fluid that meets CARDONE criteria (see article “Not All Power Steering Fluids Are Created Equal”), while also flushing with new fluid and bleeding the system every time. However, the technician also mentioned that he uses brake cleaner to wash out all the debris and build-up from the inside of the power steering lines/hoses.

This off-the-cuff statement led to further investigation into common automotive cleaning chemicals and the potential effects they could have on the steering system

Brake Cleaner, Carburetor Cleaner & Engine Degreaser


Brake cleaner was specifically mentioned above, but carburetor cleaner and engine degreaser were additionally explored, as all three are common cleaning chemicals.

Rubber components in a steering system are either Viton or BUNA material; therefore seals of both compositions were spray tested with all three chemicals at 100% concentration. Both the brake cleaner and carburetor cleaner samples began to swell 15 minutes after exposure, however, the engine degreaser had no visual change. The seals were then soak-tested for 24 hours in 100% concentration, and further degradation occurred (see picture). The results of the brake cleaner and carburetor cleaner are both undeniable, but the engine degreaser did not cause significant damage to the rubber.

Testing continued with the presumption that the chemicals would not remain at full strength when power steering fluid was added to the system, as in the case where the hoses are sprayed out. Therefore, new seals were soak-tested for 72 hours in a 10% chemical to 90% power steering fluid mixture. Results were not as dramatic as shown in the photo, but the rubber hardness did degrade. In a power steering system, where dynamic function is key during all ranges of heat, flow and pressure, even small changes in the rubber integrity can cause leaking and premature failure.

The Aftermath

The seals seemed to react well against the engine degreaser, but visual appearance is not a viable analysis method, so additional testing will be performed to analyze if any long-term effects occur.

It is understandable that technicians would use brake cleaner and/or carburetor cleaner as a method to clean the system, as both are sold in every parts store across the country, and are known to remove grease and grime better than anything else. However, the attempt to “do some good” can result in the exact opposite.

Therefore, the best advice is to avoid all chemicals completely and simply use the old-fashioned power steering flush method to remove contaminants from the system, as it will avoid introducing foreign elements into the system.

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