How to assemble Bendix front drum brakes

15 Nov 2021

When I first get a "new" car -- meaning someone's old abandoned junker with 50 years of accumulated wear and neglect -- I take brakes (and every other system) fully off the car the first time, clean, paint, and examine closely. This resets the brakes life to zero, essentially. Next time brakes need work I do it on the car as per usual practice. But this first time around, there's often hidden damage or wear. It also makes for good photographs.

The shoes contact the backing plate in three places, these often have deep wear grooves. If that's the case, they must be welded in and ground flat. If not, the brakes will never work right; the shoes catch in the grooves, the shoes are not square to the drum, and these issues make pedal feel and braking uneven and unpleasant. These backing plates were in good shape, somehow.

Note that there is a non-stock screened hole in the backing plate; these are my hot-rodded drum brakes. Ignore the hole; they're otherwise correct.

Assembly procedure

Very little text. I think the photos get the job done.

This is a passenger side, right side, assembly. Left and right are mirror symmetry. The self-adjuster is always towards the rear of the car, Bendix or Wagner, front or rear.

The front shoe is called the leading shoe, the rear is called trailing.

Wear areas shown here. I probably should have welded the two lower ones.

There is a left and a right wheel cylinder on most front brakes; rears sometimes have the same cyl left and right, with a center hose location.

The wheel cyl bolts are just 1/4-20, but short with small heads. They are not under great load, substitute Grade 5 no problemo.

Bendix shoe holddowns are these funny square anchors that press in from the back side. You might have to tap them through. Align the hole intentionally (up, down, etc) so you can find it in the next step.

Here's my home made holddown spring tool. 3/16" bent rod.

Place a shoe onto the backing plate, insert the holddown spring, positioning it so that the hook end is lined up with the anchor, and stretch the spring with the tool, and hook the loop.

First time on "new" cars I try to use new brake springs and self-adjusters. They're very cheap, and stretched-out springs, frayed cables are a safety/reliability issue. Self-adjusters, the wheels and the toggle plate, the ratchet teeth get rounded and less likely to adjust when worn enough. New parts every 25 years is compatible with Rambler Mentality, no?

The self-adjuster cable guide plate is a PITA, in that it needs to sit perfectly flat on the shoe. Initially easy, as shown here, it tends to lift up when you insert the spring and cable (next steps). Note the rolled edge on the guide plate, that fits into the larger hole in the shoe.

The cable goes on first. Note that the crimp on the cable is up, so that the "washer" portion sits flat. This also covers the tip of the trailing shoe.

Here's where the guide plate likes to lift. Run the cable over the guide and pull tight with your fingers, and partially install the spring, and rotate the guide so that there's no binding. Things are close but when you get it right it falls into place.

If you have the right tool for the job use it, I just use a screwdriver to stretch the spring so that the hook catches the center post of the backing plate.

This is where you will find that the cable guide plate has lifted off the shoe, if it does. It must be flat. You may have to remove the spring to re-do it. Note also that the guide should not be digging into the spring; rotate it, gently, so that there's cleraance around everything. Don't bend the guide plate. Like I said, you might have to remove the spring.

Now install the leading shoe spring. The leading spring is always last, always on top.

Ready to install the self-adjusters. Note that there are left and right toggle plates and adjusters! Most parts are stamped with an L or R. Double-check that the cable runs through the guide and that the guide plate is flat on the shoe.

Place the toggle plate hook into the trailing shoe, the adjuster spring into the leading shoe.

Put a tiny bit of brake-compatible lubricant in the adjuster pivot. Graphite works fine. Note the stamped letter. The right side adjuster has left-handed threads. Thread the adjuster as short as possible here, for assemmbly.

Insert the adjuster between the lower edges of both shoes. There's a flat on each shoe meant to accept the socket. Things are loose here and the parts tend to fall out.

Hold the toggle with one hand and hook the spring into the loop with the other. It usually moves far enough to hook the spring with little effort. Pliers are fine.

Grab the toggle just below the loop with pliers, and turn the toggle towards the cable end, so far just dangling. Hook the cable into the loop.

This is the completed brake. You can tug on the adjuster cable as shown and operate the self-adjuster. The toggle will lift, and the flat blade will click over the teeth in the adjuster; releasing the cable turns the adjuster and increases the distance between the bottom edge of the brake shoes, compensating for wear. If you swapped left and right adjusters, well, you won't like how it works. Note that the toggle might not catch the teeth, when the adjuster is screwed all the way in like this. In this case manually turn the adjuster longer a few turns.

Here's the drivers side, assembled. Note the mirror symmetry.





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