1979-1985 Buick Riviera Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 1979-1985 Buick Riviera the front brakes wear out first, usually well before the rears. These are heavy front-wheel-drive coupes with the engine and transaxle sitting over the front axle, so the front discs do most of the stopping. The rear is where owners get caught out: rear discs were an extra-cost option when this Riviera launched, so a given car may have drums or discs back there, and the disc version uses a caliper with the parking brake built in that needs a specific procedure.

How the Brakes Are Laid Out on This Riviera

The 1979 Riviera was Buick's first front-wheel-drive Riviera, built on GM's E-body alongside the Oldsmobile Toronado and Cadillac Eldorado, with the longitudinal V8 front-drive layout those cars already used. At launch buyers could choose the Oldsmobile-sourced 350 V8 or, in the S Type, Buick's turbocharged 231 V6.

Front disc brakes were standard. Rear disc brakes could be ordered for an additional charge, which means the rear axle on any surviving car is one of two designs:

• Rear drums with shoes, wheel cylinders and a cable-operated parking brake inside the drum.
• Rear discs with a single-piston caliper that carries its own parking brake lever. This is the GM caliper design that hot rodders later nicknamed the Cadillac-style caliper, and it works very differently from a front caliper during service.

Before you order a single rear part, pull a rear wheel and look. A drum hides everything behind a solid cast face; a disc car shows a rotor and a caliper with a parking brake cable running to a lever on the back of it.

Front vs Rear: What Wears First and Why

The pattern owners see most is simple: the front pads wear to the backing plate and the rear pads or shoes still have plenty of lining. On a disc car, the exception is a rear caliper whose parking brake mechanism has rusted or seized. It can hold the pad lightly against the rotor, wearing one rear pad set much faster than the other and making the rotor run hot.

Symptoms and How to Tell Which End Is the Problem

• Grinding or squeal on light braking, felt through the pedal: almost always front pads worn to the wear indicator or metal-to-metal.
• Car pulls to one side under braking: usually a front caliper sticking on its slides or a collapsed front hose. Check both front pads for uneven wear.
• Hot smell and one rear wheel much hotter than the other after a drive: a dragging rear caliper or a parking brake that is not fully releasing.
• Parking brake pedal goes nearly to the floor or will not hold the car: on drum cars, worn shoes or stuck adjusters; on disc cars, a rear caliper that has fallen out of adjustment because the parking brake is rarely used.
• Low fluid with no visible front leak: pull the rear drums and look for a wet wheel cylinder.

The Rear Disc Caliper: Why It Needs Special Handling

The rear caliper on four-wheel-disc cars uses a spring-assisted lever that mechanically pushes the piston against the pad to hold the car. Internally the mechanism takes up clearance as the pads wear, and regular use of the parking brake is what keeps it adjusted. If a car sat for years, or the owner never set the parking brake, the gap between pad and rotor grows and both the pedal and the parking brake suffer.

That design changes the pad job:

1. Do not clamp the rear piston straight back like a front piston. It must be rotated back into the bore with a wind-back tool that engages the slots in the piston face.
2. With the caliper reinstalled, cycle the parking brake lever repeatedly so the mechanism takes up the clearance.
3. Check that the lever rests just off its stop. Classic Performance Products gives a lever position of 1/16 to 1/8 inch from the stop on these calipers; if it is outside that, the adjusting shaft needs to be set before the system is bled.
4. Connect and set the parking brake cables after the calipers are adjusted.

Classic Performance Products warns that failing to adjust the parking brake lever can cause no brakes, dragging brakes, overheating and premature wear. If the lever or piston on a 40-year-old caliper will not move freely, replace the caliper rather than fighting it. Replacement rear calipers for these cars come in left and right versions because the lever sits on opposite sides; browse replacement brake calipers and confirm the side before ordering.

What to Replace, and What to Replace With It

Front brakes

Replace pads in axle sets and inspect the rotors for thickness, heat checking and a lip at the edge. On a car this old, new rotors are usually a better use of time than machining rusted originals. Replace the caliper slide hardware and clips at the same time; seized slides are the most common cause of uneven front wear. Shop front and rear brake pads and brake rotors, and add a brake hardware kit.

Rear drum brakes

Replace shoes in axle sets along with the springs and self-adjusters, and replace any wheel cylinder that shows fluid behind the boot. See our brake shoes.

Rear disc brakes

Replace pads in axle sets and inspect the rotors. For a quiet, low-dust option, the EBC Redstuff ceramic rear pad set for the 1979-1985 Riviera uses an aramid fiber, ceramic-granule compound that EBC says cuts dust substantially and contains no steel fiber. EBC also notes this is a hard-wearing pad that can take as long as 1,000 miles to fully bed in, so expect the bite to improve over the first several hundred miles.

Every brake job on this car

• Inspect the rubber hoses; original-era hoses can swell internally and hold pressure on a caliper.
• Flush the fluid. Old fluid absorbs moisture and corrodes the parts you just replaced. Use the fluid type printed on the master cylinder cap or in the service manual.
• Torque caliper and wheel fasteners to the values in the factory service manual.

How Hard Is the Job?

Front pads and rotors are a straightforward driveway job for anyone with jack stands and basic hand tools. Rear drums are moderate; the spring hardware takes patience. Rear discs are the hardest of the three only because of the parking brake mechanism: plan for a wind-back tool, time to adjust the lever, and possibly a pair of calipers if the originals are seized. If the parking brake does not hold firmly and the pedal is not high and firm afterward, do not drive the car until it is sorted.

Frequently Asked Questions

Does my 1979-1985 Riviera have rear disc or drum brakes?

It depends on the car. Front discs were standard and rear discs were an extra-cost option, so check by removing a rear wheel before ordering parts.

Should I replace front and rear brakes at the same time?

Not necessarily. The fronts normally wear out first. Replace the rears when their lining is low, when a caliper or wheel cylinder is leaking or sticking, or when rear wear is uneven side to side.

Why will my rear caliper piston not push back in?

On rear-disc Rivieras the piston is part of the parking brake mechanism and must be screwed back in with a wind-back tool. Forcing it with a clamp can damage the internal adjuster.

Why does my parking brake barely hold after new rear pads?

The integral parking brake needs to be cycled and adjusted after the pads go in. Work the lever repeatedly and check its position against the stop before bleeding.

Are ceramic pads a good choice for a car this old?

For street driving, yes. Ceramic compounds like EBC Redstuff run cleaner and quieter than many semi-metallic pads. Allow for the bed-in period before judging pedal feel.

Sources

1. Conceptcarz: 1979 Buick Riviera - front discs standard, rear discs an extra-cost option
2. Mac's Motor City Garage: Buick Adopts Front-Wheel Drive - E-body shared with Toronado and Eldorado, engines, front-drive layout
3. Classic Performance Products: Adjust Cadillac Caliper Parking Brake Lever - self-adjustment through parking brake use, lever position, consequences of poor adjustment
4. OnAllCylinders: How to Adjust a Cadillac-Style Rear Parking Brake Caliper - spring-assisted lever pushes the piston to hold the wheel
5. EBC Brakes: Redstuff Ceramic Brake Pads - compound, no steel fiber, dust reduction, bed-in distance