On Sat, 16 Sep 1995 Bruce wrote:
> No flames intended...
>
> >i have always thought dual circuit brakes were uncle sam's best idea and
> >the idea of a warning light to suggest a leak in one circuit before
> >catastrophic failure is also a great idea,
>
> Although I agree that the warning light is a good idea, I do question its
> usefulness. Speaking from experience, you will notice a brake problem at
> least as soon as the PDWA warns that you have one, and I have found that
> the warning lags the problem by a great deal. In fact, as someone noted on
> this list a while back, the PDWA can probably cause trouble as you have
> a) that sinking feeling in your brake pedal, and b) see a very large, red
> light
> pulling your attention to the dashboard from the road.
I'm not sure I understand how "the warning lags the problem by a great
deal." I suppose it's possible that, if you (generic "you") are a
gentle user of the brake pedal, you could possibly not be pressing the
pedal hard enough to throw the switch in the PDWA. In my experience,
though, with a number of PDWA-equipped Triumphs, failure of the system
to do its job is usually a function of a DPO, in mucking about with the
wiring, disconnecting the wiring from the PDWA, not replacing the
warning light bulb, etc. Beyond that, they seem to work as intended.
> That said, I personally don't recommend removing the PDWA from the brake
> circuit, nor will I do that myself. But I just think that relying on it to
> warn of brake problems is optimism at its best. :)
Regarding the need for such an item, functional or not: one supposes
that an enthusiast such as we all purport to be would recognize brake
problems early on: by always being sensitive to pedal feel, pulling or
grabbing brakes; and by often inspecting the entire system for
leaks, etc. Like it or not, this level of sensitivity and awareness
cannot be assumed for the masses. Therefore, we have warning lights to
tell us that it is likely we won't stop before hitting that Senior
Citizen Tour Bus, and we have buzzers and chimes and lights to tell us
to buckle up, so that when we hit that Tour Bus, we won't launch
ourselves through the Triplex and into the bus.
How well does the PDWA warn? I can't say for sure, as I've usually not
waited for it to tell me there's a problem. I imagine, under the right
circumstance, you might get an overly sensitive PDWA to tell you, in
effect, that your rear brakes are so badly in need of adjustment that it
threw the switch trying to get them to work. I don't think that's a
likely scenario. Now take Mr. and Ms. Average. Put them in identical,
say, Spitfires with the PDWA disabled (electrically, of course, not
hydraulically). One has badly out-of-adjustment rear brakes; the other
has a pinhole leak in the rear half of the system. Have them drive each
car, then ask them to tell you which system leaks and which needs only 5
minutes with a wrench on the adjusters.
I suspect at least one of them will "guess" incorrectly, and it is for
that reason why the rest of us put up with warning lights. Not all of "us"
need to rely on the PDWA circuit, but enough of "them" do. ;-)
In fairness, though, I will mention that I'm not particularly fond of
the way the warning system in my mom's 1984 Volvo does NOT seem to work.
I drove it briefly about a week ago, and I suspected that something was
amiss. It was not until after her mechanic replaced the front pads (which
did need replacing) that he diagnosed an internal seal failure in the
master cylinder. Under certain circumstances, the pedal does slowly sink
towards the floor; the warning light has yet to come on.
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* Andrew Mace e-mail: amace@unix2.nysed.gov *
* NYS Library phone: (518) 474-8541 (voice) *
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