Document 2jX81vYB7nX2bKr3yy2KDJL35

M U LTIB E S TO S; HANDBOOK FOR.B R A KJE. SERVICE HYDRAULIC BRAKE SYSTEMS A--Rex* &--Platon C--Comp*ntlnR Port HoU D--Primary Cup Cp-!Vcom1ai7 Cup F--Vent G--Boot H-- U'sa.Ser I--Spring Oto 9rVe Sv*tem K^Piiof Cffpa !* -- (Mil. 11 Vent Cap iJ it(. * * ! nVf V*v* 0---0ul !rt Valv? P--ti Spring Wd*Hr * Fit?. 2 ` Spring Stup R--TeJIet Port S --Boot CHp T--Double Chock Valve Fig. 2 Box Type Master Cylinder Bi El Fi Di FjEe Fir. - Step-Bore Wheel Cylinder A'--Outer Ca*^g B*--RobSeT Soot C -^onneet'ng Link D1 --P!ton Cup Koturo Spring ' --Pltton 2--Smeller Putao Ft--Pietoa Cup FJ--3metf*r Putaa Ct Ci-BMir Va>o 44 Bi Tire bjrdnwlle wheel cylinder need o* the SteeldranlJc brake U ehown in Pig. 5. Note the see of a rigidly held rabbet diaphragm*. Bf At t' S' t! Fig- S--Wheel Cylinder MUL.TIBESTOS HANDBOOK FOR BRAKE SERVICE TThE master cylinder shown in Fi*. 1 is the integral tank master cylinder (compensating type) in common use on 'ate model cars. The Barrel Type cylinder (not shown) is on the same pr;nciple, except that a dash type gravity supply tank it used. The Box Type master cylinder (Fig. 2) is the same as the barrel type except that the master cylinder itself is submerged in a reservoir of hydraulic fluid instead of having a dash supply tank. The plain mastet cylinder (non-compenaa#ing) is a simple cylinder used in con junction with a dash supply tank equipped with a plunger pump t*> replace fluid lost by seepage or when bleeding the system. Compensating type cylinders: 1. Constantly maintain the correct volume of fluid under varying heat conditions. 2. Constantly maintain the correct volume of fluid under extreme cold conditions. X Automatically replace fluid lost through gravity seepage or slight leaks. 4, Eliminate pump in supply tank necessary during bleeding operation. \Wheet cylinders, although differing slightly in appearance, all operate under the tame principle as the cylinder picture in Fig. 3. The workings of a hydraulic system are as follows: 1. Depression of foot pedal causes piston (B) and cup (D) to move forward in the cylinder barrel. A very small movement forward of cup (D) close* com pensating port hole (C) and the pressure stroke commences. 2. Fluid is forced through copper tubing and flexible hose to the wheel cylinders, which, under hydraulic pressure, causes the wheel pistons (E.) and connecting links (Ci) to move outwardly againet brake shoes, thus expanding the shoe* and lining against the drum. The column of fluid being incompressible and auto matically maintained at the correct volume, is, by the principle of hydraulics, transmitted to all surfaces with equal and undiminished force. This assures equalisation ol pressure at all four wheel cylinder*. 3. Removal of pressure from brake pedal permits return of pedal and push rod (A) to their off position and return of piston (B) and cup (D). Removal of hydraulic pressure at the wheel cylinders allows return of the brake shoes to relaxed position because of tension of return brake springs. 4. The construction of the above type of compensating cylinder equipped with a secondary cup (E) allows fluid on both sides of the primary cup thus avoiding Air pocketing. The return to off position of piston (8) and cup (D> i* much faster than the return of fluid from the braking system through outlet (J). A* a consequence a momentary vacuum is created in cylinder barrel and additional fluid is drawn into system through drilled holes in piston (B) and past lip of cup (D) a* well a# through compensating port hole (C). As the fluid finally returns to master cylinder excess is by-passed through compensating port hole (C) back Into the reservoir. 5. Expansion of fluid due to heat, contraction due to cold or loss by seepage or bleeding system is compensated by flow in either direction as the occasion demands* through compensating port hole (C). 6. A double check valve (T) is used in all master cylinders of the compensating ype. It is held at the closed end of the master cylinder barrel by the piston cup return spring (I). This valve performs two functions: (a) It acts as a seal to prevent fluid or air being drawn into the system during the bleeding operation and prevents entire loss of fluid in case a break in the tubing occurs. (b) It maintains a slight pressure (approx. 7 lbs.) in the brake system--not suffi cient to cause the shoes to drag but enough to assure immediate action at the wheel cylinders when foot pedal is depressed. A slightly higher pressure (!C-!2 !bs.) is maintained in some of the newer hydraulic systems, Wheel Cylinder* on Some 1935 Model* 1935 Chrysler. Dodge. Plymouth, and S^udebaker cars are employing a new "Step-bore" wheel cylinder construction (see Fig- 4) in which pistons of different diameters are uaed on forward and reverse shoes within the same brake assembly. 45