Very probably. It's likely it's effectiveness will be diminished quicker than Dot4. After one very scary moment on a track with 'regular' Dot4 I used to use it in a 911 which i did track days in and was advised to change it every year. However, as I said above, IMO, it's unnecessary for road use.
I may be wrong, but I think Dot 5 isn't hygroscopic i.e. doesn't absorb water. This may sound good but the fluid will then float on top of all that water on your calipers - which isn't so good. That may be Dot 5.1 though Dot 4 is more than good enough for the road
Yep Dot 5 is silicone based, won't mix with anything else. Dot5.1 is glycol based and safe to use if Dot 4's been in there before.
Just to clear your confusion Harry, DOT5 is silicon based, doesn't absorb water and doesn't mix with other brake fluids. DOT5.1 is a conventional glycol based fluid but with a higher boiling than DOT3 and DOT4. Read more about them here.
That's right - as I was typing I thought - hold on am I talking about dot 5 or 5.1, anyhoo - stick with 4 for the road
My Monster 1200 had a soft brake lever too which would come up great with one quick pump. Then after a short period of only a few seconds was back to soft again. The mechanic who bled it for me to try and remedy explained it as the pistons binding slightly on the seals, which would then "rock" as the lever was squeezed instead of the piston sliding further through the seals. This would then cause the pistons to retract further than they should, on releasing the lever, as the seals "rocked" back to their relaxed position. Made sense but I never got to the bottom of it, and they stayed like that, the lever not quite coming back to the bar. I adjusted the lever out a bit to compensate...
Update, bled it myself with DOT4 and nothing more complicated than squeeze, squeeze, open/close nipple, release. Lever is as firm a week later as it was at bleed, even after running a track day, with the brakes engaging straight away. Verdict? They do not all do that sir, suspect poor bleeding on the dealers behalf, this isn't the first negative experience I've had with them but I dare say it will be my last.
