[Diy_efi] OT: ABS retrofit into older car...

[Shannen Durphey]

Adam Wade wrote:
> 
> However, it's far more important to maintain control
> with the front wheels, since they steer the vehicle;
> thus single-axle ABS is almost exclusively on the
> front axle.

Not true.
GM vehicles.  First app that I know of ABS is Oldsmobile, 1969, rear axle
"anti skid" electric brake control.  Offered on Cadillac in different forms
also.

Second "modern" abs application by GM that I'm aware of was in 1988 with
advent of new bodystyle pickups.  Brake bias in utility vehicles has always
been an issue.  Adding Rear Wheel Antilock allowed GM to remove the
mechanically activated, height adjusted bias valve.  This same RWAL was
added to S10, van, and RWD minivan platforms.  Rear wheel antilock braking
systems are also used in medium and heavy duty trucks, with both air and
hydraulic brakes.

> 
> Volkswagen had an ingenious solution for their
> Transporter in the 60s and 70s...  They had a
> tiltmeter in the form of a ball-bearing check valve.
> the harder one hit the brakes, or the more the rear
> lifted in a stop, the less it would bias the rear
> brakes.  As long as the system had the fluid changed
> yearly, it worked incredibly well.

GM's valve on pickups consists of a lever attached to the rear axle. 
Changes in height changed brake bias.  As long as one didn't use the truck,
the system worked incredibly well. ; )
Shannen

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