Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Power Brake Units - BENDIX Single Diaphragm: Overhaul: Disassembly
- Scribe mark housings for reassembly. Remove master cylinder from power unit and set aside. Remove front housing seal and piston rod. Attach assembly to suitable holding fixture (J-22805).CAUTION: Ensure proper tool alignment to avoid damage to check valve in front housing.
Loosen lock nut and remove push rod clevis and lock nut, if equipped. Remove dust boot retainer, dust boot, and silencer from diaphragm plate extension. Partially straighten four deepest tabs on rear housing. Place suitable wrench (J-9504) over studs on rear housing and attach with nuts and washers. Press down on wrench and rotate rear housing clockwise to separate.
CAUTION: Housings are under internal spring tension.Remove wrench from housing.
- Remove air filter from diaphragm plate extension. Remove diaphragm from groove in diaphragm plate.CAUTION: Protect and handle diaphragm carefully.
Hold diaphragm plate so that push rod is in horizontal position. Depress rod slightly and rotate piston until air valve lock falls from diaphragm plate hub. Remove reaction disc from diaphragm plate bore (use push rod, or suitable tool, to push disc from seat).
CAUTION: Do not chip diaphragm plate. - Remove rear shell bearing seal with punch or screwdriver.CAUTION: Remove seal only if new one is available.
Do not reuse seal if it has been removed. Remove vacuum check valve and grommet.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.