Re: brake conversion

["Nigel Heron" <nigel@psycode.com>]

"Ayham Eid Idrees ." wrote:

> what is the proportioning valve , i may know it under other name

if you look at the master cylinder you'll see 2 thin cylinders that are
attached before the rear brake lines start (the front brake lines don't
have them). Those are proportioning valves, they don't let the max
pressure of the master cylinder reach the back brakes immediately. Think
of as kind of bleeding the pressure gradually so that the rears don't
lock up all of a sudden... eventually the full pressure will reach the
rears, but because it came on more gradually there's less likelihood of
locking up. The proportioning valves that come on cars with rear disks
work at a different rate than those used with drums.

A2 golfs/jettas (and probably many others, A3, A4??) use a variable and
adjustable proportioning valve system, it's mounted on the rear trailing
arm. When there is more weight in the trunk the trailing arms lowers and
causes more rear braking. When the front dives or when there is less
weight in the trunk then there is less braking in the rear (lowering an
A2 screws this up).

A1s don't have adjustable valves, but you can buy levers/knobs from
Summit, Wilwood, etc. that can be added in to get the best ratio.

-nigel.


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