Quote:
Originally Posted by kevinshea
Glenn .. thanks for the reply..
I got a price from White Post (who bought out Ed) for the Midland for $595.
OR i can get a new PBR vh44 out of Australia for about $400 including shipping.
The VH44 has a 3/4" bore.
The generally available VH44 (chinese) from Ebay have a 5/16" bore.. Cheap at 64$. but could prove to be "undersized"
I believe this is a mistake by the Chinese in description. I bet the 5/16" is referring to the "VALVE PISTON ASSEMBLY" and NOT the slave cylinder bore.
-5/6" OD slave would NOT move enough fluid volume
- The Chinese copied the AUS design! and they sure wouldn't come up with a change leading to a non-functioning booster.
I will be installing a JEGS vacuum canister to be sure that I have plenty of Vacuum.. my 59AB has an ISKY 77 B cam that may draw down vacuum.
Very unlikely that you need this. Try without it first making sure you use an intake manifold vacuum source
So I am currently researching to see if one is "better" than the other.
One thing for sure tho is that I will be using wilwood proportioning valve to assure the I can balance the system.
If you keep a dual pot master cylinder with drums all around, just boost the front brakes. For this setup, you MAY need to the proportioning valve but for the front brakes.
As noted I have a dual Master .. don't remember the manufacturer, but it is a very common unit. My 40 brakes are all stock lockheed. I operate the system with stock 35 pedals and the mechanical brake crossbeam arm. Master is mounted midships
BTW I am in Old Orchard Beach.
Almost missed that :-)
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"All power brake systems use engine vacuum to assist the normal operation of the brakes. Utilizing a vacuum cylinder or chamber with a diaphragm inside, they increase the brake line pressure and decrease the driver’s effort needed at the brake pedal to stop the car. Engine vacuum from the intake manifold acts on one side of the diaphragm, and valving devices let air (at atmospheric pressure of 15 pounds psi) in on the other side. As you depress the brake pedal, air is let into the cylinder, and the difference in pressure between the vacuum side and the atmospheric side causes the diaphragm to move. The diaphragm moves a rod connected to the master cylinder’s piston and increases the brake fluid pressure to the wheel cylinders. After the brake pedal is released and the supply of atmospheric pressure is cut off, springs in the cylinder return the diaphragm to its normal position and stop the assist action.
With the integral-type units, the diaphragm works directly on the piston of the master cylinder, but with the
multiplier types we are concerned with here, the power brake unit has its own hydraulic cylinder. Mounted away from the master cylinder, the multiplier is connected to the master cylinder by a hydraulic line. The diaphragm works the piston of its “slave” cylinder, which in turn is connected by a line to the wheel cylinder junction fitting on the frame, and the slave cylinder adds the necessary extra braking pressure to the wheels.
When the brake pedal is held at a steady position, pressures on the diaphragm are equalized by a control valve, slowing down the assist action so you don’t lock up the wheels every time you step on the binders.