What brake fluid???

This is an easy one. What is the best brake fluid for my S70R auto? and why?

[the great one]

dot 4 volvo use

[bobcat]

volvo now use dot 4+, but i would go with at least dot 5.1. if you have a look around you can even find brake fluid that will exceed this like ate superblue etc.

but i would just go with any off the shelf dot 5.1.

Originally Posted by garnet red

and why?

As others have said, minimum of DOT 4 but the higher the better.

Bobcat recommends DOT 5.1, reason being it has a higher boiling point so you will suffer less brake fade. The higher the number though the more hydroscopic it is and thus the more moisture it will absorb. However, changing it every two years should be sufficient.

DOT 5 is silicone and I believe is not suitable for our cars. I have heard though that it is suitable but just can't be mixed with non silicone fluid thus requiring a thorough flush of the system.

Personally I'd avoid DOT 5 and go with Bobcat's recommendation of 5.1.

Regards

Andy

[Simon J]

Originally Posted by mraldonnelly

The higher the number though the more hydroscopic it is and thus the more moisture it will absorb.

Are you sure about this? DOT 5.1 a has higher wet boiling point than DOT 4 (191 C compared to 155 C) so it can probably absorb more water before boiling than DOT 4, but I don't think it is therefore more hygroscopic.

[pyaap]

I'm currently using Redline R600+ and I've not managed to boil it over yet; can't say the same for all the others I've tried though. In my experience, the only other brake fluid I've tried which I think is better than the R600+ is Castrol SRF but its silicone based.

Originally Posted by garnet red

This is an easy one. What is the best brake fluid for my S70R auto? and why?

I reccomend the ATE Superblue. You can see exactly when you flushed your old fluid out and not waste any. When the blue is in, I then switch to ATE Type200 clear and just alternate between the two. They are both identical, ie boiling points and characteristics, and are one of the best brake fluids out there.

Kevin

[Engineer]

Interesting one this, hydroscopic used widely and comes up ok on most spell checkers but not in the dictionary, hygroscopic does however. In either case there is a lot of opinion from brake fluid manufacturers and experts on the absorb rate of water by different dot fluids.

So use a brake fluid tester once a year for road cars and after every meeting for race cars. Silicon dot 5 for long term stationary vehicles show cars etc. as any water absorbed into the brake lines due to usage in silicon fluid will not be absorbed and will cause a spongy pedal as found by old F1 pilots).

Now we have a base line lets use the best wet temp. manufactures figures for dot 3, 4, 5.1 we can find. Having said that some claim 60 months service change schedules for synthetic fluid. dot 4, 5.1. I want my mum.............

[Simon J]

The correct term is hygroscopic.