Dot 3 or Dot 4

Technical Area Engine, Transmission, Exhaust etc
1

I am about to replace a leaking slave cylinder on a uk 1994 mk1.
Reservoir caps say only use DOT3, I guess that was before dot 4 came along?.

Is it safe to new seals to use dot 4?, I will replace all clutch fluid, its mostly gone anyway!.

2

Dot 3 and Dot 4 are compatible, so in theory, yes OK to use dot 4. But lots of different types out there. I just put castrol dot 4 fluid in my NC but only after checking it was FMVSS116 spec as per the manual.

3

thanks, I ordered from MX5 parts as that was all they offered so guessed it must be alright!!

4

Yes, no worries there.