> +--Roger Garnett writes.....
> | 3) Another Castrol vs. Silicone brake fluid comment: If you have only
> | drum brakes, (early A's, Spridgets, other older cars) you should be less
> | prone to brake fluid heating/bubbling, than if you have disks. (calipers
> | seat directly against the hot pads, where a cylinder only pushes against
> | the edges of the shoes) Therefore, you should be able to use silicone
> | with no problems. (an autocross car might be an exception- Anyone
> | autocross a car with 4 wheel drum brakes?)
> +---
>
> Well, I run an autox car w/ 4wheel drums and Silicone, and haven't seen any
> fade troubles (yet). Most local autocross courses are 30-90 seconds, and
> that just isn't enough time to overcook the brakes [...]
I agree, the drums have no problems in an autocross, or even in daily driving
when it comes to a Mini. It's only when you're trying to repeatedly stop
from >90 mph that the twin-leading shoe drums aren't adequate on a Mini. Then
again, the noticeable fade is about only 20% more stopping distance required.
The problem I'm having, after reading this thread, is that Mini drums go oval
fairly quickly. That little bit of friction on each wheel revolution seems
to heat the brake fluid to boiling, causing expansion, causing the brakes
to rub more, causing friction, causing ....... in about 15-20 minutes, the
brakes are locked up!
I used to think it was due to a bad bleeding job, but during the recent
resurrection of Herman (the autocross Mini) I was meticulous and the brakes
were fine. Four days later, they're not. So, new return springs, drums,
and shoes are on the way.
__________________________________________________________________________
Someone asked why Mini disc brakes are so expensive: it's because the entire
hub must be swapped out. There are also four kinds of disc brakes. The
997/998 Cooper discs (are worse!! than the twin leading shoes), Cooper S
discs, 12" Mini discs, and the Turbo Metro 4-caliper 12" discs. If you're
on a budget, then go for the twin-leading shoes -- conversion from the
single-shoe 850 brakes is under $200.
--
George Emery - via FidoNet node 1:105/14
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|