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Old 12-10-2004, 10:23 AM
yesgo yesgo is offline
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Here is a typical GM master with what appears to be the same size resivoirs. The front is for the front brakes. This is actually a drum/drum master, but their disc/drum were similar at first.

note that although they appear to be the same size, they are not. I just learned something too

This one is a typical distribution block with no valving. GM used the same one for disc and drum cars. This one I think is a Chrysler, but GM was very similar, save for the large weight:

note it is 5 port, with warning switch, with no button, or large nut to hold the prop spring/piston.

Here is a typical pre-71 GM prop valve used with the above valve, to reduce pressure to the rear brakes:

This one is a GM valve which holds fluid away from the front discs, allowing rear drums to catch up. It is used in the front circuit with the above:

you cant see it in the pic, but it also has a button to assist with bleeding.

Now here is a later brass combination valve for disc/drum. Note the button on the front, and the large nut on the back. Sometimes there is a nut under the button too.

and a diagram of above:

Here is a disc/disc valve. Note the lack of metering button:

GM has always used 1/4" line for the rear brakes until the axle, and 3/16" line for the front on RWD cars for as long as I can remember.

Some of their early combo valves were cast iron, and they later switched back to brass.
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