Morris Minor Owners Club

Just brought some new Brake fluid it is Dot 4 but synthetic. Can I use this in the Morris or should I return it. Looking around it seems all Dot 4 or Dot 3 is now synthetic? Thanks

Brake fluids can be mixed only if the fluid that you add to the system belongs to a higher grade.

For example, a braking system that has a brake fluid DOT 3 specification can use a DOT 4 or a DOT 5.1 fluid. Also, a system with a DOT 4 can be topped up with a DOT 5.1 without bleeding the system.

However, never top up a DOT 4 system with a DOT 3 brake fluid. DOT 3 won’t be able to meet the temperature requirements because of its lower dry and wet boiling points.

Once again, do not mix DOT 5 with any other type of brake fluid because of its silicone-based composition.

Information source: https://www.valvolineglobal.com/en-ksa/ ... omposition.

morris63 wrote: ↑Thu Aug 22, 2024 2:25 pm Just brought some new Brake fluid it is Dot 4 but synthetic. Can I use this in the Morris or should I return it. Looking around it seems all Dot 4 or Dot 3 is now synthetic? Thanks

Just marketing, Dot 3 and Dot 4 has always been Synthetic.

Regards John