Browse Publications Technical Papers 2001-01-0947

A Study on the Service Interval Performance of Borated and Non-Borated Glycol Ether Brake Fluids 2001-01-0947

There is a quite a wide range of brake fluid performance parameters affecting the lifetime of a brake fluid while in service in a car. However, in particular a high boiling point stands out as one of the most important product characteristics, in order to provide adequate protection against vapor lock in a car's brake system.
Using laboratory experiments and on the road car trials, we have investigated a number of key parameters that affect brake fluid service life. In particular we have compared the boiling performance of DOT 3 versus DOT 4 brake fluid types, i.e. non-borated versus borated glycol ether based types. The results lead us to the conclusion that DOT 4 compared to DOT 3 brake fluid offers consistently better boiling point performance; i.e. up to several years DOT 4 offers a considerable better margin against vapor lock.
Furthermore, comparing different types of DOT 4 fluids in various car trials, we obtained solid evidence that higher wet boiling point fluids offer the potential to increase the service interval, provided the brake system minimizes moisture ingestion.


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