Brake fluid

Author:  cyfa2809 [ Mon Feb 07, 2011 10:02 pm ]
Post subject:  Brake fluid

do i have to use the brakes own brand? i.e hayes for my hayes brakes


Author:  ajantom [ Mon Feb 07, 2011 10:42 pm ]
Post subject: 

No :D

But some people don;t recommend mixing old/new fluids, so it is suggested that you drain out the older stuff first................but I've mixed Dot 5.1 motorbike brake fluid with the existing stuff in my Hopes before, and not died yet!

Author:  cyfa2809 [ Mon Feb 07, 2011 10:51 pm ]
Post subject: 

cheeeeeers for replying :wink:

not sure on what fluid to 'experiment' with :? was just looking at getting more as my hayes fluid (dot 4) has run out and i now have an empty hayes nine line :evil:
only needs a few more drops too!

do i need to look at dot5 or whatever?
recommended is dot 3 or 4
just didnt want to buy the hayes one as i can get a litre for the same price as 4oz! :shock:
mobil too

Author:  ajantom [ Mon Feb 07, 2011 11:30 pm ]
Post subject: 

Use the same Dot - so if hayes fluid is 4, use 4. Hope uses 5.1, so I use 5.1, etc.
Apparently you can mix different synthetic Dot fluids (3,4,5.1) but it's not recommended.

Author:  mountainloz [ Mon Feb 07, 2011 11:32 pm ]
Post subject: 

i'd stick to the recommended dot 4 etc, however you aren't tied to hayes fluid
you can use any really
just flush your system through with the new stuff :)

Author:  cyfa2809 [ Tue Feb 08, 2011 12:16 am ]
Post subject: 

nice one guys!
just what i needed
the irony is i probably only need a teaspoon or less now :lol: :lol:

but i know i have more brakes to bleed in future 8)

maybe i should buy the mercedes one :lol: even thats cheaper than the hayes fluid

think of how cool i would be! 8)

Author:  teethgrinder [ Tue Feb 08, 2011 12:28 am ]
Post subject: 

Ordinary car brake fluid is perfect. DOT 4 is only a few quid for half a litre and 5.1 isn't much more. Both are PEG based but 5.1 has a higher boiling point.

DOT4 is compatible with systems that use DOT5.1 (but NOT DOT5 which is silicone based) but as said, make sure all the old fluid is flushed.

Mineral oil is the work of Satan. And Citroen. And isn't compatible at all with DOT fluid.

Author:  cyfa2809 [ Tue Feb 08, 2011 12:32 am ]
Post subject: 

is dot5.1 compatible with dot4 systems?

not sure to male the jump or not, the dot4 has been fine for me so far.
what are teh advantages of dot 5.1 othe than higher boiling point?

Author:  teethgrinder [ Tue Feb 08, 2011 12:53 am ]
Post subject: 

4 and 5.1 are compatible as long as thoroughly flushed. the higher BP (both dry and wet) means less brake fade as the fluid has to reach a higher temp before boiling, turning into vapour and becoming compressible...not what you want on hydraulic brakes!

Whilst I don't think mtb brake discs get quite to the temps car discs get to, the bike has a much smaller volume of fluid and therefore heats up faster.

Brake fade is somewhat FAIL.

TBH 4 will be fine. I didn't know the history of my Hopes and erred on the side of caution.

Author:  cyfa2809 [ Tue Feb 08, 2011 1:13 pm ]
Post subject: 

ok i see

went with 4 in the end 8)

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