[DML] Re: Pressure (was Vacuum) brake bleeding

["daveswingle2" <dswingle@xxxx>]

I know this will probably start another Brake Fluid Holy War, but 
here goes. 

You probably ought to keep looking for the Castrol. Any quality DOT-4 
is *probably* OK, but I've heard that the Castrol for some reason is 
the most compatible with the natural (as opposed to synthetic) rubber 
used in the DMC braking system. 

DOT 5 is a whole 'nother animal. That is Silicone fluid. Not a good 
idea to mix with DOT 3/4. (It won't mix, you'll get a barrier region 
between the two.) BTW - the DOT5 containers often say NOT to use it 
at all in ABS (not an issue)systems OR in clutch hydraulics. It is 
slighly more compressible than DOT 3/4, so you could see some clutch 
issues. 

DOT 5 is popular with the collector-car crowd because it does not 
attack the paint when it does leak. That's really the only advantage. 
It also does not absorb water, but IMHO that just means that you'll 
end up with water bubbles in the fluid instead of absorbed into the 
fluid. Better to stick with the real stuff and change it every year 
or two. 

Dave Swingle



> Also, I'm using Castrol GT-LMA brake fluid, but I only have one 
quart left.
> If I run out, and need to add more, and I can't get any more GT-LMA 
(it's
> hard to find), what's the next best compatible brake fluid I can 
use? DOT 4?
> DOT 5?