Brake fluid type

[sutton4ord]

Will 5.1 brake fluid be ok in osf or should you stick to dot4 might have to put master cylinder in the old girl,Think higher the dot higher the heat range ?

[LEONMEX]

I was always led to beleive that if you change to dot 5.1 it can only be on a brand new brake system as it reacts with dot 4 & swells the rubber seals up. Any trace of dot4 is enough to react so keep with the dot 4 if i was you. I was told this by a delphi lockheed engineer who develops fluids so i guess he knows what he is on about

[baz105e]

dot 5 has a higher boiling point

[gearbox100]

I beleave dot 5 is the stuff that reacts with dot4 , but dot5.1 is fine , just less water in it to a higher boiling point

[sutton4ord]

I did notice it reacted rebleed with dot 4 thought 5.1 was a bit to thin see how it goes