Electronic Brake Controllers

[John Hofstetter <hofs@domain.elided>]

>Tom, Dan, Epp,
>  From my experience with both types, Tom's absolutely right.  My '77 had 
>the hydraulic type, which I removed in a brake line replacement project, 
>but then replaced it with the electric/plumb weight type.  I didn't relize 
>there was a plumb weight that varied the amount of braking, I just thought 
>it was it was a constant level of braking.  What you say makes more sense, 
>living is learning.;)
>- ---
>Layda,
>Tark
>'77 Terra 345/T19/D20
>   Survivor of '98 Scout Nationals
>
>"there are two kinds of electric (or electronic)
>brake controllers. The kind that actaully hooks into your brake hydraulic
>lines and uses the pressure there for reference (the best he tells me).

Digesters,
I'm sometimes guilty of being a bit overly simplistic in explaining how 
things work. I did this to Tom in the belief that the concept was more 
important than detail. I'm referring to the "plumb bob" type of 
electronic brake controllers. The early ones actually had a physical 
plumb bob to sense the tow vehicles deceleration and apply current to the 
trailer brakes proportionately. These were sensitive to "level" and you 
had to adjust the sensitivity first of all to compensate for levelness, 
and then you adjusted the rheostat to determine how much braking you got 
at any given amount of unplumbness. In the more modern versions 
deceleration is determined by electronic devices and levelness of the 
control unit is no longer particularly relevant. But the plumb bob effect 
still explains how it works even without the plumb bob better than any 
other way I know of to explain it. I might also point out that the 
electronic controls are activated by the stop light circuit rather than 
the mechanical switching of the old hydraulic units.

As far as I'm concerned the hydraulic controls are much much better than 
any of the electronic controllers and whatever one may think of ABS 
brakes, the demise of the old style controllers was a negative event 
attributable to them. (I happen to be a proponent of ABS brakes, having 
had a real life potential accident prevented by my ABS brakes, but ......)

John Hofstetter