In a message dated 10/14/98 4:58:17 PM Eastern Daylight Time,
Daniel1312@aol.com writes:
<< Any conventional DOT 3 fluid will be fine. If you work the brakes hard it
is
worth using a DOT 4 fluid which ultimately is less kind to the seals >>
OOPS! NO, NO, NO! As I'm sure you heard from MANY others, NO DOT 3 BRAKE
FLUID. It will eat the seals in LBCs.
DOT 4 is the way to go. Castrol LMA is DOT 4 and came in the car when new.
DOT 4 works fine.
DOT 5 is silicone brake fluid, and please don't start the discussion of
whether silicone or DOT 4 is better. I did that and it took a month to get it
out of the system! BTW, DO NOT use DOT 5 (silicone) in any new car with ABS.
There is no lubricant in it to keep the hydraulic pump working.
The results of that last thread is that if you totally rebuild the brake (or
clutch) hydraulic system, you can successfully use either DOT 4 or DOT 5 brake
fluid, and live happily ever after. MY PERSONAL OPINION is that if you are
building a show car and are overly concerned with paint being destroyed by
brake fluid, rebuild the system and use silicone. Silicone will not absorb
moisture as easily as DOT 4 (even LMA) and will not have to be flushed as
frequently. Proper bleeding is very important with DOT 5 to remove all
trapped air and any moisture that is also trapped with the air. The moisture
will settle and cause rust if not removed. Good idea to bleed the system
annually when using DOT 5.
Otherwise DOT 4 will actually work a little better because it is less
compressible, as long as you change it (flush, refill, bleed, bleed, bleed) on
a regular basis, perhaps every year or two.
There is also a DOT 5.1 which is NOT silicone, but a different formulation of
DOT 4. I have no experience, hence no comments on DOT 5.1. Read about ALL
fluids used in cars on the Vintage Triumph Register Web site, www.vtr.org.
Allen Hefner
'77 Midget (about to rebuild ALL the hydraulics)
'92 Mitsubishi Expo LRV Sport (with ABS)
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