I run DOT 5.1 in Monty, as already covered by RichardV6 if you're stuck you can top up with DOT4 no trouble at all.

DOT 5 on the other hand is silicone fluid and definitely not compatible with 4 & 5.1, I'm just back from the Le Mans Classic and that mistake (by a well meaning mechanic) nealy took the Aston out of the game.



I flushed it through and bled it up on good old DOT 4 and I did get the clutch back, but the slave seals were very swolen and knowing that situation would only get worse I was surprised we we're able to complete the trip. TBH I would'nt have wanted to do another day more because by day six we were getting through a whole resevoir of DOT 4 a day!

Don't mix it folks, as soon as I saw the tell tale 'oil & balsamic viniger' spots in the empty reseviour I knew exactly what had gone on, a classic case of... "A little knowlege is dangerous" frown

Of course the good old TR3 saved the day, a quick trip to the local mechanic and we were back at the Aston holding a fresh half litre of DOT 4 thumbs

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