Hudson Terraplane K 1934 Mechanical Procedure Manual page 190

SECTION 14
Page 8
The movement from both the hand brake and the foot pedal
is transmitted to a rotary equalizer mounted under the frame "X"
member, to which the rear brake operating cables are also
attached. An adjustable pedal push rod (10), Figure 1403, pro-
vides an adjustment for determining the amount that the me-
chanical application of the rear brakes will lag behind the
hydraulic application. Normally only hydraulic application is
made when the foot pedal is depressed.
Figure 1405—Master Cylinder
THE MASTER CYLINDER
Description
The master cylinder, Figure 1405, consists of a supply tank
cast integral over the master cylinder proper, in which compen-
sating features are incorporated.
This unit performs two supplementary functions. Its first
function is to maintain a constant volume of fluid in the system
at all times, regardless of expansion (heat) or contraction (cold).
The second function is its action as a pump during the bleeding
operation.
The return to released position of piston (2), Figure 1405, and
cup (4) is much faster than the return of the fluid through outlet
(10) into the master cylinder. A momentary vacuum is created
in the cylinder barrel and additional fluid is drawn into the
system from the reservoir through the drilled holes in piston (2)
and past the lip of cup (4). The pressure exerted on the fluid by
the brake shoe retracting springs is sufficient to lift valve (16)
off its seat to permit the fluid from the lines to return into the
master cylinder. Any excess is returned by port (3) into the
reservoir; thus we have a cylinder full of fluid for the next brake
application.
It is imperative that rod (1), Figure 1405, which is attached to
brake pedal operating rod, be adjusted for clearance where it
seats in piston (2), so that there is 1/4" free movement of brake
pedal pad before the pressure stroke starts.
HUDSON-TERRAPLANE
This will permit cup (4), Figure 1405, to be clear of port (3)
when piston (2) is in its released position; otherwise the compen-
sating action of the master cylinder will be destroyed and the
brakes will drag.
Secondary cup (5) prevents fluid from leaking out of master
cylinder into boot (7). Supply tank filler cap (11) is conveniently
located, accessible under the left side of engine hood for checking
fluid level. Supply tank should be kept at least half full of fluid.
CAUTION: Before removing supply tank filler cap (11), Figure
1405, extreme care must be used to prevent dirt from entering the
master cylinder.
The use of other than Genuine Hudson Hydraulic fluid or the
introduction of oil with a mineral base into the system will cause
the rubber parts to swell and become inoperative. Grit and abra-
sive substances permitted to enter into the fluid reservoir will
cause the cylinder barrel to become scratched or pitted. When
either of these conditions occurs it becomes necessary to remove
master cylinder for inspection.
Disassembly
After removing the master cylinder from the car, the unit is
disassembled as follows:
Remove large boot strap (12), Figure 1405, that fastens boot to
cylinder casting. This permits removal of boot, link and small
boot strap. With a sharp- pointed screwdriver remove retainer
spring (13) from its groove. This permits the removal of internal
parts. Rubber parts and cylinder bore are then checked.
If inspection shows cylinder walls scratched or pitted it be-
comes necessary to have the cylinder walls honed to renew the
highly polished surface necessary for efficient operation. All
Wagner Branches have the equipment necessary to recondition
cylinders.
After cylinder has been honed and new cups procured it is
recommended that reassembly be made in the following manner:
Wash castings and parts in clean alcohol, dip casting and parts
in Genuine Hudson Hydraulic fluid for lubrication purposes.
Install valve (16) and return spring (9) as shown in Figure 1405.
Assemble primary
Figure 1406—Wheel Cylinder