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Drum Brake Restoration

Inexpensive project to make your vehicle safer

Many restorers can only dream of taking their vehicle off the road to do a total ground-up restoration. For most it's too large a commitment of money, time and, quite frankly, the garage space to do it. A good alternative is to restore while you drive. The advantages are obvious—your favorite vehicle isn't off the road for years at a time and the drain on the family budget is more gradual. The key to being successful with the restore-as-you-drive-approach is to concentrate on one area of the vehicle at a time, prioritize the mechanical aspects to make it a safe and dependable driver first, then concentrate on the cosmetics later. Our '69 Buick GS 400 is a perfect example. It badly needed new universal joints so we removed the driveshaft, fully cleaned and painted it, installed new U-joints and put it back in the car. A couple of paychecks later we removed the trailing arms, cleaned and painted them, installed new bushings and hung them on a totally "ugly" rear end housing. In this installment we will clean, detail and rebuild the rear drum brakes, which leaves only the axle tubes and differential housing to clean and paint. By then, the entire rear end and driveshaft assembly will be restored and the car will have been off the road only one day at a time.

Prep

Restoring drum brakes (front or rear) is quite simple and inexpensive. Because most collector vehicles since 1965 feature front discs and rear drums, we will cover restoring rear brakes. To get started you need to jack up and support the rear of the vehicle with jack stands and remove the wheels and tires. Make sure that the emergency brake is off so that you can remove the brake drums. Our Buick had a little surface rust around the axle flanges and where the wheel studs fit through the drums so it took a few light taps with a dead-blow (soft plastic) hammer to get the drum off. If it's really stubborn, remove the rubber adjuster plug and back off the brake show adjuster to take pressure off of the drum.

With the drum removed, a quick visual inspection will tell you how involved this resto segment will be. The brake wheel cylinders located at the top between the front and rear brake shoes can leak. If they are leaking, you will see wetness near the ends of the cylinder. If that's the case they need to be rebuilt or replaced. Now is a good time to check and see if the axle seals are leaking too. Leaking axle seals or bearings must be replaced or the brake rebuild will be a waste of time and money. If either the wheel cylinders or axle seals have been leaking, your brakes won't have been working very well or possibly locking that wheel under hard braking.

Assess

Our Buick GS was in pretty good shape. The wheel cylinders look like they had been recently replaced and the axle seals were intact. The brake shoes had lots of material left but the drums were heavily scored and didn't look that good. Someone must have done the last brake job without turning down the surface of the drums. And this is an important step to make sure the drum surface is totally round and the braking surface is smooth and clean. One obvious item on the Buick was that the small brake parts such as brake shoe anchor pins, return springs, and spring seats were pretty beat-up and had never been replaced.

Tools

We made a plan of attack. First we got the brake drums turned at our local parts store ($20 labor charge). Next we purchased a small parts kit that comes with enough springs and anchor pins for both brakes (about $6). We purchased a set of new brake shoes because the others were heavily scored ($10 total!). And finally, we purchased a couple of cans of spray brake cleaner, a rotary wire brush for the cordless drill, some semi-flat black paint and a small container of gray cast-iron high-temp paint from a restoration company.

Disassemble

Before we disassembled the shoes and emergency brake system, we took a digital photo just to remind us where everything fit. A Polaroid camera or a good shop manual will accomplish the same thing. Next with the two brake tools shown we removed the springs, shoes and all of the actuation levers and adjusters. The levers and adjusters were given a soak in the solvent tank. Next we sprayed the axle, wheel cylinder and backing plate with brake cleaner and wiped them off with shop rags. Any surface rust was ground off with the cordless drill and rotary wire brush. Be careful that you don't contact any of the rubber seals with the wire brush or the job will just get more complicated by replacing those seals.

Install

Next, we wiped all of the surfaces to be painted down with enamel reducer to clean off any grease or brake dust residue. We taped off the wheel cylinder and sprayed the backing plate with a rust preventative paint. Then we pulled the levers and adjusters out of the cleaning solvent and dried them off prior to re-assembly. The new anchor pins, retainers and springs were used to reinstall the old shoes after putting a dollop of grease on the backing plate where the edges of the shoes rub. A little grease was also used on the threads of the star adjusters and the new brake springs were carefully pried in place with the special brake tool (be sure to wear safety glasses for this operation). The final touch was to bead blast the outside portion of the brake drum to remove the ugly rust and give them a coat of cast-iron gray high-temp paint. The Buick drum brakes are heavily finned and look great when cleaned up.

Adjust

If your vehicle needed new wheel cylinders you'll need to bleed the brake hydraulic system now before you proceed with the brake adjustment procedure. After the fresh coat of cast iron gray paint is dry, just slide the drums over the studs and axle flange. Our Buick has automatic brake adjuster mechanisms so we simply assembled the brakes with the adjusters screwed all of the way in. Simply driving the car easily and applying the brakes several times will adjust the brakes.

A little known fact is that new brake shoes need to be "bedded in." This simple but important procedure requires a series of short hard stops from 30 mph. Let the brakes totally cool down (about 15 minutes), repeat the process and you should be good to go. Our total tab for this Saturday project was less than $50. Not bad when you see the results and know that your vehicle is one step closer to a total restoration.