On Sat, 20 Aug 2011 23:16:37 -0400, micky
wrote:

On Sat, 20 Aug 2011 21:32:03 -0400, wrote:

On Sat, 20 Aug 2011 20:47:28 -0400, micky
wrote:

On Sat, 20 Aug 2011 19:57:34 -0400, wrote:


"Never tap into your vehicles brake hydraulic system... " Who's going
to do that!!!


Used to be the only way to get trailer brakes. All the brake
controllers were hydraulic over electric.

Wow. I guess that fully explains their warning, but it sounds
awfully hard to do, both at the car end and the trailer end.

Dead simple, actually. Remove the line from the master cyl (single in
those days), install a "T" and run the line to the controller. The
controller sent a varying current to the brakes, propoertional to
brake pressure.

I think the Toyoat manual was talking about something else. It said
it "would lower the braking effectiveness" which to me meant using the
hydraulic pressure of the car to apply the brakes of the trailer.
Which means running a hydraulic line from the car to the trailer!

Just using the pressure to run the controller a few inches away
wouldn't hurt braking effectiveness at all, would it? I assume the
line to the controller was bled. .
No - not alarmist - and it COULD reduce braking efficiency. The
hydraulic/electric systems are NOT RECOMMENDED on dual braking systems
- much-less anti-lock. ANd Toyota is not speaking of a different
system. I used to be a Toyota Service Manager, back when dual diaganol
braking systems, and dual circuit systems in general, first came into
use. At the same time, electronic brake controllers became REQUIRED.

So now I've changed my mind and it still sounds alarmist by Toyota.

Trailer end was the same as today. I installed dozens
- possibly hundreds of them over the years.