Brake Fluid

[DuaneCollie <drcollie@xxxxxxxxxxxxxxx>]

>A couple of posts in the last digest made me think
>of a question: does brake fluid changechemically or something
>when it has been boiled(i.e., with the result being that the boiling
>point is lower in future)?  I think I may have boiled mine at the track. 

Andrew,

Brake fluid is hydroscopic - which means it absorbs moisture like I absorb
Rolling Rocks. Over time it deteriorates and the boiling point becomes
lower.  So, if you start out with 500 degree brake fluid, it will degrade
to 450, then 400, then 300 etc.  The higher the boiling temp (in general)
the more expensive the brake fluid.  Castrol makes a brake fluid for Indy
cars that is very expensive ($ 80.00 + a quart and is non-compatible with
conventional brake fluids) but has a much higher temp rating near twice
that of Super Blue. 

You can test the boiling point with various tools ranging from handheld
computerized devices to simple dip strips. If your boiling point stays up
high there really is little need to change it.

Your brake pads generate gobs of heat, which transfers to the caliper and
hence the fluid.  Once it boils - you're screwed.  That's why everyone who
really starts honkin' at the track changes their fluid to the racing fluids
(like Super Blue)for the higher temp. ratings.

You can loose a head gasket at the track, drop a muffler, etc. and not
suffer any damage.  But loose the brakes and you're in a world of hurt.
Hence the constant harping to stay on top of brake fluid changes.

Duane Collie
RM3DR1/UUC/PizzaFest II
National Capital Chapter

------------------------------