Re: Front disc brakes for 1941-47 Clippers

Posted by jfrom@kanter On 2013/4/24 12:34:10

Quote from post #12:

"Secondly if you stay with a BTV you may need to install a residual valve to the brake system."

Did u mean to say proportioning valve as opposed to residual (pressure) valve????? The BTV already has a residual (pressure) valve in it from the factory.


I did mean residual valve


Residual Valves are used in both front and rear brake systems in the following ways

2 psi residual valves are used in the front of a disc brake conversion when the master cylinder is at or below the height of the calipers, the residual valve acts as an anti siphoning valve preventing fluid siphoning back to the master cylinders when the brake is released. But be aware in the case of a BTV unit, as they are equipped with a check valve. The check valve would then have to be removed as it would be redundant and caused the calipers to stick.

You would know that your system would need a front residual after converting if it takes more than two pumps of the pedal to get a good strong high pedal.

10 psi residual valves are used in a rear drum brake setup (when converting to front disc) to prevent air from being sucked in to the system when the pedal is released. Typical wheel cylinders seals will only seal when there is pressure behind them. In a system without a residual valves the rapid release of the pedal cause a vacuum inside the brake system which relaxes the seals and can cause either induction of air to the systems or leakage of fluid. By keep a 10 psi on the wheel cylinders this prevents this from happening. Depending on what master cylinder you are using it may already be equipped with an internal residual valve.

A proportioning valve goes in the rear in the case of a disc brake conversion and provides CONTROL of the rate at which pressure within that part of the system rises.


Thanks
James From
Kanter Auto Products