It depends. When a car uses four wheel drum brakes on a single chamber MC
they usually build the rp valve into the Master cylinder, a spring and
rubber ball are a crude rp valve. I'm not sure how the stock spridget MC
works for a drum/disk car. They may have compromised and used a low
pressure rp valve and just put up with having to push a little farther the
first time you engage the drums. A modern MC has the rp valve built into
each output line on the MC - normally 2lb for disc and 10 lb for drum. On
my 4 wheel disk brakes on the 46 Willys I found that not putting the 2lb rp
valve in caused a need for an additional pedal pump to get enough pressure
in the brakes.
I'd be curious to hear how the stock spridget system handles this. one of
the mods I was planning on was to install a dual chamber MC to guard againt
total brake failure.
Chuck p
http://home.off-road.com/~chuckp
46 CJ2a
65 MG Midget (Wifes ride - eventually)
I seem to remember when I rebuilt my MC, that there is a rubber non-return
valve
on the brake side (dual master). Doesn't that pretty much take care of this
issue, or at least partially address it??
- Bryan
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