> After 15 years of driving, the same
> brake system remains rock solid plus I never blistered paint
> with the occasional spill. Doesn't silicone wear easier on
> rubber seals?
Overall, that has been my experience. New seals seem to last longer with
DOT 5. For example, I rebuilt the front calipers on my previous TR3A back
around 1987 and switched to DOT 5. That car is gone, but those calipers are
still working fine on my current TR3. Even the bleed screws opened up
easily!
The problem (if any) seems to only arise with seals (and hoses) that have
been run for a long time (decades) with DOT 3/4. It doesn't always happen
even with really old seals, but sometimes they turn to goo when run with DOT
5.
IMO the benefits outweigh the downside; so I'd say that if you can't change
seals, it's still worthwhile to make the change. I've done that several
times, and it has usually worked out OK. So I certainly won't way you "have
to" change seals or hoses.
But if you want your best shot at never having hydraulic problems again,
then new seals, new hoses (preferably braided SS over teflon), new aluminum
cylinders if the old ones are anything less than perfect, and new caliper
pistons (again if the old ones aren't perfect) is probably the way to go.
It's been a few years back, but I watched a fellow unload a very nicely
restored TR4 from it's trailer at Triumphest in Ventura. Beautiful car, a
definite contender for first place in the "Funcours". Then he opened the
bonnet to see why the brakes didn't work, and found a huge patch of
wrinkled, ruined paint streaming down the firewall from a master cylinder
leak. He touched it with a finger, and the paint came off. I don't know
how much it cost to repair that; but I'll bet it was a heck of a lot more
than a bottle of DOT 5.
ISTR they gave him the "Uff da" award (for best hard luck story), but I
don't imagine it was much comfort.
-- Randall
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