On Wed, 8 Jun 1994, Greg Meboe wrote:
> Dear SOL'ers
>
> I've been thinking about designing a progressive brake system for my
> car, and I would like some other opinions. It's my street car, but with
> I'd connect the master cylinder pushrod to an adjustable lever arm actuating
> a conventional pressure reducing valve. System variables would be: Initial
The actual travel of the pushrod from min to max brake application is
probably very small once shoes and pads make contact, so the valve would
have to vary brake proportioning over an extremely narrow range of motion.
I'd think it would be hell to get and keep adjusted. Then you would hit
the brakes hard, the fronts would lock, and as you backed off a bit, the
rears would lock...
It sounds a bit like the electric brake controller I bought for our horse
trailer. It was more expensive than a conventional controller, but
avoided cutting into the hydraulic system of the tow vehicle. A pendulum
swung forward when the tow truck slowed and through a rheostat applied the
electric brakes of the trailer. Trouble was, if I slowed while going down
hill, the pendulum swung further from an already forward position and
applied the trailer brakes so hard that the whole rig came to a sudden
stop even if I took my foot off the truck brakes completely. It was
disconcerting on the interstate, to say the least, and could only be
avoided by adjusting the trailer brakes so they barely worked at all on
the level.
Anyway, I expect you could work it out with enough engineering. The
question is, why? If your rears are locking under heavy application, bias
it forward a bit and leave it there. Under light application, it won't
matter.
This will probably wind up triggering more megabytes than the infamous
"improve your cooling by welding your thermostat shut" thread.
Ray "I have no data, but a hell of a conviction" Gibbons
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