Cadillacs of the '50's have always been among my favorite cars. They were cars that really stood out; you always knew they were coming by that Cadillac grin, and then when they were leaving with those classic tail fins. I remember in 1952, at age four, when my Uncle Claude came to visit us in his '51 Black 4-door. The sight of that overstuffed Blue-gray interior, the power windows and crests everywhere, became part of an experience I never forgot. In the mid-nineties, I was fortunate to find a '54, low-mileage Coupe deVille in Azure Blue with a White top, fully optioned, with power steering, windows, seats, air conditioning, Autronic Eye, Continental kit and sabre wheels! Aesthetically, the car just needed a little detailing, but it did need some mechanical and a/c work (see the Archives section). We were told by the previous owner that the brakes were new, but I never felt that they were working at 100 percent. About a year ago, we replaced the rear shoes and wheel cylinders, when we noticed a wheel cylinder leak on the drivers side. We were able to find the original type shoes with riveted-on linings and a 1/2" heat dissipating groove down the center. At that time, we also had the brake booster professionally rebuilt. When we put it back on, we were told by the rebuilder not to bleed it, but just to bleed the wheel cylinders in the usual way. As we later found out, this was incorrect information. After making these repairs, we continued driving the car periodically, but it still had the same problem--a hard pedal, and needed excessive pedal pressure to stop.
The Cadillac factory manual for Bendix (1) lists the following under Brake Troubleshooting:
Problem: Hard Pedal & Excessive Pedal Pressure; Causes: Brake shoes improperly adjusted, Brake Pedal or Linkage bind, Lining making only partial contact with drums, Incorrect linings, or Linings glazed.
Wanting to get this fixed once and for all, we decided to remove all drums front and back, and go through the system. The rear brakes were correct and wearing evenly(linings showed no high or low spots and were making contact with the drum all the way around). Upon inspecting the fronts, we found that the linings were not correct. The primary lining was an inch short of the 11.45" X 2 1/2" X 1/4" called for in the manual, and the secondary lining was over an inch short of the 12.92" X 2 1/2"X 1/4"as the manual indicated. The linings were also not hitting the drums uniformly, having high and low places all along the surface. Incorrect linings making partial contact with the drumsis exactly what the manual listed under Extreme pedal pressure. Once we had installed the correct new shoes, and put everything back together, we made preliminary adjustments to all of the brakes, adjusting them so that the wheels turned freely with just a little drag (heard and felt). It was now time to bleed the system. The factory manual states that on cars equipped with power brakes, bleed the power cylinder first, by attaching a bleeder hose to the fitting on the end cap (lower bleeder), pump brakes up and hold while backing off the bleeder ¾ of a turn, holding the brake pedal until bubbles cease. Repeat until there are no more bubbles. Tighten the bleeder, then bleed the upper valve until the bubbles cease, then tighten the bleeder. Always check the master cylinder while bleeding the brakes, keeping it topped up and not letting it run out of fluid (DOT 3 brake fluid is OEM for this car).
We then bled the wheel cylinders, right rear, then left rear; right front, then left front. With everything back together and bled, we readjusted all of the brakes and hand-rotated each wheel to setthe shoes in the drums. They turned freely with a slight drag, so we were ready for a road test. To break in the old style asbestos linings, we drove the car at low speeds and applied the brakes lightly a number of times, letting them seatthemselves. Later, we road-tested on the interstate and off-ramps at high speeds. It was a big improvement! The '54 now stops with a more secure feel, making it more likely that well drive the car on a regular basis. I think this happens a lot with old cars. There is that one thing that is not major, but is just annoying enough to keep you from jumping in and feeling secure about the car. Just a little time and research could make it just the way you want it. See you next month--and, oh yeah, watch for an upcoming article on Replacing a Brake Light Switch on a '54 Cadillac. I discovered that was not working while going through the brakes! Keep 'em driving!