1975-1978 Nissan 280z Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 1975-1978 Nissan 280Z the front disc pads almost always wear out first, because the front brakes do most of the stopping and the rear drums are held back by a combination valve. The rear shoes last much longer, but the rear wheel cylinders, self-adjusters and parking brake parts are where these cars tend to give trouble with age. Replace pads and rotors in front axle pairs, and service the rear drums as a set when you are in there.

How the 280Z Brake System Is Laid Out

The 280Z uses a split system: disc brakes up front and drum brakes in the rear. According to the factory-style repair data for the 1976-77 cars, the front brakes are Girling-Sumitomo dual-piston fixed calipers, and the rear brakes are leading-trailing shoe drums. The system is hydraulic, fed by a tandem master cylinder and a Master-Vac vacuum power booster.

The tandem master cylinder runs two separate circuits, one for the front discs and one for the rear drums. That matters for diagnosis: a leak in one circuit leaves you with the other, and a brake warning light tied to the combination valve comes on when pressure drops in either the front or rear circuit.

The rear drums on the S30 Z cars are finned aluminum with cast-iron liners. The parking brake is cable and lever operated and locks the rear drums, and working the parking brake is also what drives the rear self-adjusters.

Why the Front Brakes Wear First

When a car stops, weight shifts forward onto the front tires. The front tires then have more grip, so the front brakes are sized and plumbed to do the bulk of the work. On the 280Z the combination valve limits rear pressure to prevent premature locking of the rear wheels, which keeps the rear drums from ever working as hard as the front discs.

The result is predictable: front pads go first, and front rotors come next because they absorb the heat. Rear shoes on a Z that is driven normally can outlast several sets of front pads. That does not mean you can ignore the rear. On a car this age, the rear is where parts stick, leak or stop adjusting, often long before the linings are worn.

Front Brake Symptoms and What to Replace

Signs the front brakes need attention:

• Squeal or grinding when braking, especially at low speed.
• Pulsation in the pedal or steering wheel, which points at uneven rotor thickness.
• Pull to one side, often from one fixed-caliper piston sticking.
• Low pad material. A common replacement point used on these cars is 3/32 in. (2.4 mm) of friction material or less.

Pads: the front pad for the 1975-1978 280Z is the same shape used on the 240Z and 260Z. Hawk lists its HB169F.560 HPS front pad, which is 0.560 in. thick, for the 1975-1978 280Z as well as the 240Z and 260Z. Browse our brake pads for classic and import cars or the ceramic brake pads collection for a quieter, lower-dust street pad.

Rotors: 1974-1978 260Z and 280Z front rotors are a shared part, but they are matched to the round-style front wheel bearing hubs used on those years. Confirm your hub before ordering; a rotor built for a different hub will not bolt up the same way. See our front brake rotors.

Calipers: the fixed dual-piston caliper does not slide, so uneven wear from one side to the other usually means a sticking piston or a torn dust boot. A caliper that pulls or drags should be rebuilt or replaced in pairs. Our brake calipers collection covers replacement units.

Rear Drum Symptoms and What to Replace

Signs the rear drums need work:

• A pedal that sinks further than it used to, or a parking brake lever that pulls up too many clicks. Both point at shoes that are no longer adjusting.
• Wet brake fluid on the inside of a rear tire or the backing plate, which is a leaking wheel cylinder.
• A rear wheel that drags or gets hot after a drive, from a seized wheel cylinder or a parking brake cable that will not release.
• Scraping from the rear, usually a shoe worn to the rivets or a broken return spring.

Because the rear self-adjusters work off the parking brake, a car that is rarely driven with the parking brake used can creep out of adjustment. Before you blame the master cylinder for a low pedal, check the rear adjustment and cycle the parking brake.

When the drums come off, replace the shoes on both sides together, inspect or replace both wheel cylinders, and fit a new brake hardware kit with fresh springs. Old springs lose tension and can let the shoes drag. Shop rear brake shoes to match.

What to Replace at the Same Time

• Front pads and rotors together. New pads on an uneven rotor can bring back pulsation quickly, and Z owners commonly replace both at once.
• Rubber brake hoses. On a car this old, the flexible hoses can swell internally and hold pressure on a caliper. A braided line kit is a common upgrade; we carry the Russell stainless braided brake line kit for the 1975-1978 280Z. You can also browse brake hoses.
• Brake fluid. Any time you open the system you need to bleed it, and a common recommendation is to flush it at least every two years. Use the DOT fluid type specified on your reservoir cap or in your owner's manual.
• Front wheel bearings, if the hub comes off. A rotor job means pulling the hub, so it is a good time to repack or replace the bearings with high-temperature wheel bearing grease and a new seal.

How Hard Is the Job?

Front pads on the 280Z are one of the easier brake jobs on any car. The fixed caliper stays on the knuckle for a pad swap, and the pads come out once the retaining pins and anti-rattle clips are removed. Rotors take more time because the hub has to come off, which means dealing with the wheel bearings.

The rear drums are more involved. The shoes, springs, wheel cylinder and parking brake linkage all have to go back in the right order, so work one side at a time and use the other side as a reference. Torque the caliper mounting bolts and wheel nuts to the values in the factory service manual, bleed the brakes starting at the wheel farthest from the master cylinder, and bed in new pads before normal driving.

If you are unsure where to start, our full brake parts catalog is a good place to match each part to your car.

Frequently Asked Questions

Does the 1975-1978 280Z have rear disc brakes?

No. The factory setup is front disc brakes with dual-piston fixed calipers and rear leading-trailing shoe drum brakes. Rear disc conversions exist but are aftermarket modifications.

How often do 280Z rear brake shoes need replacing?

Much less often than the front pads, because the combination valve limits rear braking. On most cars the rear wheel cylinders, springs and adjusters need attention from age before the shoes wear out. Inspect the rears every time you do the front pads.

Are 240Z, 260Z and 280Z brake pads the same?

The front pad shape is shared. Hawk lists the same HB169 front pad for the 1970-1973 240Z, 1974-1975 260Z and 1975-1978 280Z. Front rotors differ, though: 1974-1978 260Z and 280Z rotors are matched to the round-style hubs.

Why does my 280Z brake pedal feel low?

The most common cause is rear shoes that have drifted out of adjustment, since the rear adjusters rely on the parking brake. Other causes are air in the lines, a leaking wheel cylinder, swollen rubber hoses or a worn master cylinder.

What does the brake warning light mean on a 280Z?

It works off the combination valve and indicates a pressure drop in either the front or rear hydraulic circuit. Check the fluid level and look for a leak before driving.

Sources

1. Datsun 280Z 1976-77 Brake Repair Manual - front Girling-Sumitomo dual-piston fixed calipers, leading-trailing rear drums, self-adjusting via parking brake, tandem master cylinder and Master-Vac booster, combination valve and warning light
2. ZCarGuide: Replacing Front Brake Pads and Rotors in a Datsun S30 - finned aluminum rear drums with cast-iron liners, separate front and rear circuits, 3/32 in. (2.4 mm) pad replacement point, bleeding every two years, rotors with pads
3. Hawk Performance HB169F.560 - 0.560 in. HPS front pad listed for 1975-1978 280Z, 260Z and 240Z
4. The Z Store: Front Brake Rotor, 74-78 260Z-280Z - shared 1974-1978 front rotor requiring round-style wheel bearing hubs