Re: Re Residual Pressure Valve

[Matt Haas <mhaas@xxxxxxx>]

Note that Frank's procedure is just for Bendix type master cylinder's. 
Wagner master cylinders have a nut that you have to remove (it's knurled, 
not threaded -- TSM says put the master in a vise and use locking pliers to 
get it out) and then you remove the small rubber valve, the metal plate 
behind it, and the spring behind the metal plate.

One other thing to consider with disc brakes is that a lot of the systems 
use 1/4 inch brake lines (I have no idea if AMC did on any or all of their 
systems). This is because disc brakes need more fluid volume than drums. If 
the donor car had 1/4 inch brake lines to the front, you'd be well advised 
to put 1/4 inch lines in the car getting the disc brakes and the larger 
master cylinder that was designed with that fluid volume in mind.

Matt

At 08:45 PM 6/4/2005 -0400, you wrote:
> That's not right Bill, you can remove the valve. It's behind the valve seat.
> 1. Find a screw that will fit the hole in the center of the small hole in 
> the valve seat after you remove the hose. Screw it in 2-3 threads at 
> least. The screw should protrude out enough to grab it with a pair of 
> pliers or better yet a claw hammer.
>
> 2. Pull the seat out with pliers or hammer.
>
> 3. A piece of black plastic/rubber should come out along with a spring. 
> You might have to lightly tap the brake pedal to pop it out, but most will 
> come right out.
>
> 4. Put the seat back in, tap the screw with a hammer to seat it good, then 
> remove screw and put line back in.
>
>
> As long as the bore is the same in the master cylinder it can be used for 
> drum or disc brakes. The stroke is the same. The only reason the front 
> disc reservoir is bigger is to idiot proof the system. There's enough 
> fluid in there to keep the brakes working even if you never check the fluid.
>
>
> On June 4, 2005 Bill Strobel wrote:
>
> > Larry.  If you added disc brakes to your car but did
> > not change the master then that is the problem.  Drum
> > brake systems use a 10 lb residual valve in the master
> > to keep the shoes nearer the drum.  If you swapped for
> > discs up front then the master is slightly holding
> > pressure out on the pads hence the dragging.  In a
> > disc setup the cut seal at the piston maintains enough
> > outward pressure to keep the pads near the disc.  You
> > can not just remove the residual valve as it is
> > machined into the master, you need to get the correct
> > disc/drum master for your application.  Check the TSM
> > circuit for the master and you should see the residual
> > valve.  Hope this helps,

mhaas@xxxxxxx
Cincinnati, OH
http://www.mattsoldcars.com
1967 Rambler American wagon
1968 Rambler American sedan
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