I know the Copen takes Dot 3 brake fluid, but as that's getting harder to find, has anyone used Dot 4?
Out of interest, how often do you change your brake fluid? Is the recommended every 2 years too often? I was always told brake fluid absorbs water, so with hard braking, this can heat up and turn to steam creating bubbles and spongy brakes. But is this really true? Rex.
I change mine every two years, along with the air filter. In Ireland, you will fail your NCT (Irish MOT) for dark brown or black break fluid, as it severely degrades performance. You may be reported to the police if you drive out after failing on this, as you fail in the "unsafe to drive" category (in reality, this never happens for brake fluid). Yes, it is hydrophilic (attracted to water), so it will degrade over time due to moisture in the air - which is why it comes in such small bottles. It will also eat a hole in your hand / paintwork / floor, if you leave it there.
Thanks everyone. Dot 3 boils quicker and I prefer Dot 4, but I thought I'd check in case there was some peculiarity with copen that it couldn't handle the viscosity of Dot 4. Rex, every 2 years to change the break fluid is a sensible time. I've always done the brakes on all my cars and just combine it with new pads and anything that needs attention on the brakes.
I've not done brake fluid change much. Left it to main services. But with doing more servicing I will be doing it. Though hadn't planned on every 2 years lol probably nearer 3. But thats mainly due to laziness. I think by the time your oil is that dark number 6 it is either way passed 2 years or you have some other issue.
