Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
3.
Turn master cylinder over, then pump pushrod by hand to remove any remaining brake fluid.
4.
Clamp master cylinder in a vise, with vise jaws gripping mounting flange and fluid ports pointing up.
CAUTION: Do not clamp master cylinder body in vise.
5.
Remove lock ring and primary piston assembly from cylinder bore.
6.
Apply compressed air to secondary outlet port to remove secondary piston spring and retainer.
7.
Using a 13/64 inch drill, enlarge hole in tube fitting insert of fluid outlet holes. Place a heavy washer over outlet hole, then thread a 1/4 X 20 X 3/4
screw into insert. Tighten screw until insert is unseated, then remove insert, screw and washer.
8.
Remove primary and secondary seal from secondary piston.
INSPECTION
Clean all parts not included in repair kit with brake fluid.
CAUTION: Do not dry with compressed air.
1.
Inspect cylinder bore for scoring and corrosion. Replace master cylinder if necessary.
2.
Polish discolored or stained cylinder with crocus cloth, then rinse in clean brake fluid. Ensure compensating port is clean.
ASSEMBLY
Lubricate all rubber parts with clean brake fluid prior to installation.
1.
With master cylinder in a vise, insert brass tube fitting inserts from overhaul kit into outlet holes.
2.
Using spare brake line tube, thread tube nut into outlet hole and turn down until tube fitting insert bottoms into outlet hole. Remove tube nut and
inspect outlet hole for burrs.
3.
Install inner secondary seal into groove in secondary piston.
4.
Install primary seal over end of secondary piston, with flat side of seal against flange of piston.
5.
Install outer secondary seal into groove in end of secondary piston.
6.
Install secondary piston spring retainer into secondary piston spring, then place the retainer and spring over end of secondary piston, with retainer
seated inside lip of primary cup.
7.
Hold master cylinder with open end down, then place secondary piston assembly into bore, with spring seated against end of bore.
8.
Clamp master cylinder in a vise with open end of bore facing up.
9.
Insert new primary piston assembly, spring end first, into bore.
10.
Hold primary piston down, then install lock ring in groove on inside of bore.
11.
Install new reservoir diaphragm into reservoir cover with beaded side out, then secure cover onto cylinder.
12.
Install master cylinder in vehicle. Bleed brakes.
Bendix Type
Master Cylinder
DISASSEMBLY
1. Remove master cylinder from vehicle.
2. Clean outside of master cylinder, then remove reservoir cover and diaphragm.
3. Drain brake fluid from reservoir, then remove reservoir attaching bolts and reservoir.
4. Remove O-ring, compensating valve seals, valve poppets and springs.
5. Depress primary piston, then remove snap ring.
6. Remove primary piston assembly and piston return spring.
