Brake fluid
 

Just about to finish the brakes on the '42, Wondering if I should go Dot5 or Dot3 for brake fluid. Is dot5 better for a vehicle that is not used alot? Is it safe on the rubber parts in wheel cylinders?

Re: Brake fluid
 

dont i say Dont use dot 5 ,use the dot 3 or 4 ,

Re: Brake fluid
 

Using DOT 5 in a DOT 3 or DOT 4 system without proper flushing will cause damage to the seals and cause brake failure. DOT 5 brake fluid is not compatible with anti-lock brake systems. DOT 5 brake fluid absorbs a small amount of air requiring care when bleeding the system of air.

[edit] Boiling points

Minimal boiling points for these specifications are as follows (wet boiling point defined as 3.7% water by volume):

Boiling point ranges [2]




Dry boiling point

Wet boiling point



DOT 3

205 °C (401 °F)

140 °C (284 °F)



DOT 4

230 °C (446 °F)

155 °C (311 °F)



DOT 5

260 °C (500 °F)

180 °C (356 °F)



DOT 5.1

270 °C (518 °F)

190 °C (374 °F)

Re: Brake fluid
 

Thanks Willie, Dot 3 it is!!