> I've never used dot 4.
Just to clarify my earlier comment, both DOT 3 and DOT 4 (and DOT 5.1) are
glycol-based brake fluids. Among other bad things, glycol will attack
paint, and promote rust underneath the paint. There doesn't appear to be
any effective It also absorbs moisture, and should be replaced every few
years when used in a car, like our LBCs, that leave the top of the MC open
to the atmosphere. (American cars have had a rubber bladder since the 60s,
for this very reason.)
DOT 5 is silicone-based, and will not attack paint (or absorb moisture).
(In fact, many car finish preservation products contain silicone, as it's an
excellent preservative.) The biggest problem with silicone is that it will
cause "fish eyes" if you try to paint over it ... it even protects the paint
from new paint !
> Now let me see if I have this straight; the leaky
> m/c that I replaced last year was probably what ruined the
> booster, if I replace the booster, the new m/c probably won't
> leak. Is this the correct assumption?
Yes, that's right. However I'm very worried about your statement that you
have to add fluid weekly. That says you have a pretty big leak somewhere,
and a leaky seal may be on the verge of failing completely.
In fact, I had this happen to my Stag not long after I bought it ... I knew
the seals in the MC were bad (although it was leaking internally, not into
the booster) and was literally on my way to the shop to have a rebuilt one
installed (along with other work) when it suddenly failed completely !
Later inspection determined that both cups in the MC had torn. No idea why
they gave up the ghost at the same time, and it's at least possible the rear
cup was already torn when I got the car and I didn't know it (PDWA is
disconnected). But, it gave me plenty of warning if I had just paid
attention !
Sailing through an intersection with the brake pedal on the floor and
pulling on the handbrake with all my strength is an experience I won't soon
forget ... fortunately no one was coming and the severely faded rear brakes
were able to stop me once I got on the flat surface street.
Randall
|