What Brake Fluid...
 

I know I need DOT 4 but do I get Silicon or Synthetic??

Re: What Brake Fluid...
 

Just normal DOT4 from your local Halfrauds or motor parts shop - whatever's cheapest will do as long as it's a known brand like Castrol, Comma etc. Unless you're racing I wouldn't bother getting anything flash.

Re: What Brake Fluid...
 

+ 1 As lozzo says, any Dot 4 brake fluid.

pete

Re: What Brake Fluid...
 

not racing and looking for the cheapest named brand but do I want Silicon or Synthetic?

Re: What Brake Fluid...
 

They're all the same in reality, makes no difference.

Re: What Brake Fluid...
 

Have a look here.

http://www.demon-tweeks.co.uk/produc...07&tlgrp=MCR07


It is all personal preferences.

hope this helps.

pete

Re: What Brake Fluid...
 

Funny that I was just on that page when I came across the Silicon or Synthetic stuff, which is why I asked.

Re: What Brake Fluid...
 

Thats the answer I'm after, THANKS

Re: What Brake Fluid...
 

How much???...I got 5 litres of Comma brake fluid for about 12 quid from my local car parts shop - it works fine in all my bikes.

Re: What Brake Fluid...
 

Also have found this article....
5. "Should I use DOT 3, 4 or 5 brake fluid when replacing?"

(Thanks to Michael Ragsdale, from the race list, for some of this info.)

DOT 3 and DOT 4 are functionally very similar. 4 has a higher boiling
point, but motorcycle brake systems don't generate the kind of pressure and
temperatures that need it on the street, in general, although it certainly
won't hurt your system to put it in.

DOT 5 is very different--it's silicone based, doesn't absorb water, isn't
corrosive, is bad for some seals, is hard to bleed, and is not miscible
with 3 or 4. Stay away from it--it needs a system designed for it. And it
comes as stock item in Harley's, so it must be terrible. :->

DOT 5.1 is compatible with DOT 3 & DOT 4 (If I ever get hold of the
bonehead who named DOT 5.1...)

Here's more detail than you really want:

DOT3 is an aliphatic polyether.
DOT4 is borate ester based.
DOT5 is polydimethylsiloxane (silicone based).
DOT5.1 is borate ester based, thus its compatibility with DOT3 and
DOT4.

More information can be obtained from the following standards documents:

DOT3: SAE J1703
DOT4: FMVSS 116; proposed SAE standard J1704
DOT5: SAE J1705
DOT5.1: No SAE spec

If you are interested in obtaining copies of these standards documents, you
may order them directly from SAE at
http://www.sae.org/PRODSERV/STANDARD/gv/179.htm

According to DOT Federal Motor Vehicle Safety Standards specification
49CFR571.116 (which refers to SAE documents J1703, J1704, J1705), the
minimum equilibrium reflux boiling point requirement in deg C for each is:

DOT 3 205
DOT 4 230
DOT 5 260
DOT 5.1 260

This shows that, all else remaining the same, DOT 5.1 has a significant
advantage in heat capacity over DOT 4. Note that these specifications are
for completely dry (no H2O content) brake fluid.

Of course, all else does not remain the same and other than boiling points
and H2O content (which is very detailed in itself), most other properties
were beyond the scope of testing/interest of my friend. Any other
information should be gained from SAE, DOT or other authority.


pete