how do you tell typ...
 

[Closed] how do you tell type of existing brake fluid?

 bonj
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I need to change a hose, but i don't know if i've got 4.1 or 5 in there at the moment. The brakes are hope tech X2, the fairly newish ones.

I've got some hose on some old formula oro brakes that I don't use any more which i am hoping to use, if I can re use the existing hope fittings, so I am hoping that is the same type... if it's possible to tell?

IF it's not possible to determine is it ok to just flush it through a bit until all the old will have been flushed out?


 
Posted : 14/10/2011 12:16 pm
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dot brake fluid in hope brakes - 4 or 5.1 - compatible with each other. Just flush it thru with fresh fluid.


 
Posted : 14/10/2011 12:17 pm
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Wot he ^^^^^ said


 
Posted : 14/10/2011 12:20 pm
 bonj
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ok cheers, so it doesn't matter if there's tiny remnants of 4.1 among 5 or vv, as long as it's largely flushed through?


 
Posted : 14/10/2011 12:20 pm
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What he said.

In general DOT4 has a higher boiling point, but this drops off quicker as it absorbs moisture. So better for racers, or those who bleed their brakes regulalry.

Dot5.1 has a lower boiling point, but is more consistent as the moisture content increaces. So better for the maintenance shy who bleed their brakes rarely.

And before someone says thats not what the standard says, thats because the standard gives a minimum boiling point, it's the additives in 5.1 that prevent the wet boiling point falling that reduce the dry boiling point and you can't fail the spec for dot4 by beating the dry spec for dot5.1.


 
Posted : 14/10/2011 12:23 pm
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No such thing as 4.1 and 5 is completely different.

Dot3
Dot4
Dot5.1
Are all compatible.

Dot5 is silicone based and incompatible with all the above.

Magura and Shimano use mineral oil which is completely different again.


 
Posted : 14/10/2011 12:29 pm
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Aye, 4 or 5.1 will be fine. But 5 is not to be mixed with 4 or 5.1. Not likely that's what's in them though, reason being it's expensive and s**t.


 
Posted : 14/10/2011 12:35 pm
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Not likely that's what's in them though, reason being it's expensive and s**t.

Actualy it's quite good.
Boiling points on a level with PEG based brake fluids.
Doesn't freeze or thicken in cold weather (DOT thickens, mineral oil turns to wax as a lot of Shimano users find during the recent snowpocalyps's).
Doesnt absorb water, so as long as you don't open the system up it never needs maintenance.

It's used mainly in cold countries, and the IIRC its the standard in NATO vehicles?


 
Posted : 14/10/2011 12:43 pm
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Actualy it's quite good.
Boiling points on a level with PEG based brake fluids.
Doesn't freeze or thicken in cold weather (DOT thickens, mineral oil turns to wax as a lot of Shimano users find during the recent snowpocalyps's).
Doesnt absorb water, so as long as you don't open the system up it never needs maintenance.

It's used mainly in cold countries, and the IIRC its the standard in NATO vehicles?

Depends on the application. It's shit for performance. Very hard to remove the absorbed air from, so pedal/lever always spongy.

Its two main advantages to those who don't require performance are its non-corrosive nature (safe on ones classic car), and the fact that it isn't highly inflammable like regular brake fluid (the cause of most post-crash car fires incidentally).


 
Posted : 14/10/2011 12:52 pm