Gimme a brake!!
My dad and I were car nuts together when I was young and starting to drive. He was a Buick lover (1938 was his favorite), of course, I loved LaSalles.
His spoken theory was that you could forgive an awful lot in a car if it would start good, stop good and not overheat. We have talked a lot about overheating and about some tune-ups, so I guess it is time to talk about brakes.
We will be talking primarily about ’30s and ’40s hydraulic systems typical on LaSalles and Cadillacs, however, many principles will apply to later models prior to power brakes.
Braking comes when brake shoes are pressed against the brake drums. Both are dependent on each other for maximum efficiency. If you let your shoes wear down too far or get dirty, the drums can get scored and require turning down or replacement.
When you reline your brakes, always make sure each shoe is properly arced to its own drum. Failure to do so will greatly reduce efficiency because of uneven surface contact. You will also cause rapid lining wear. Any good brake shop can do this and you should insist on it. Relining without rearcing just means wasted money and will cause you to have to do it all over much sooner.
OK, now you have good drums and lining, let’s move on to the hydraulic system. You can still buy master cylinder and wheel cylinder rebuilt kits across the counter for most of these old cars. Rebuilding the master cylinder is not really difficult, but must be done right.
After disassembly and cleaning of the master cylinder, it needs to be honed. Don’t overdo it! You only need to get it smooth in the area where the rubber cups travel. In most of these older cylinders, you will have a small rust spot in the center of the cylinder where moisture settles over the years.
When you hone these out with a fine brake hone, you will get a better, more even surface by having the cylinder submerged in cleaning solvent. Keep the hone moving steady and even, and don’t stop the hone in the cylinder. Inspect and make sure it is smooth and clean. When you are satisfied, then make sure both ports between the reservoir and the cylinder are clean. This is important!
Then dry the cylinder well with compressed air and use a heat gun. Check the ports again. Liberally clean the insides of the cylinder again, this time with brake fluid and blow dry again. This will clean out any foreign material.
When you are ready for reassembly of the master cylinder, make sure you liberally coat all of the inside of the cylinder as well as all parts going into it, with fresh brake fluid.
When you reassemble the cylinder, it is a good time for a little extra insurance and install a new stop light switch. Make sure all connections are good and tight, and install the master cylinder to the frame before you hook up the hydraulic line; and assuming you have the wheel cylinders off, you should use compressed air to blow out all the brake line.
Now is the time to hook up your brake lines and fill the master cylinder with brake fluid, and let it set and soak while you finish the rest of the brake job. Cleaning and honing the individual wheel cylinders is simple and nearly identical to preparing the master cylinder. Clean up the backing plates and install the wheel cylinders and you are ready to start the assembly of the brake system.
Follow your service manual for reassembly. Make sure when you assemble the brake mechanism that the star wheel adjustments are all the way in and the eccentric pivot is loose; otherwise, you may have trouble getting the drums over the new linings.
Before you put the shoe and lining assemblies on the backing plate, be sure you lightly lubricate the ridges on the backing plates where the shoes ride. Failure to do so will cause some real strange noises when you apply your brakes and release them.
Once you have the brakes all assembled and the drums on, it is time to bleed them. It is a good idea to fully flush the system and even waste some brake fluid doing so. To do this right, you should use a pressure bleeder or have two people doing the job. when you bleed the brakes, always start with the wheel farthest from the master cylinder and finish with the closest. Usually, this will be right rear, left rear, right front, left front.
It is also a good idea to go through this procedure twice. The first time is primarily to flush and clean the system, and the second time to make sure no air bubbles are in the system.
Now we are ready to adjust the brakes—but we have run out of space, time, etc. due to all the news on our regional show in this issue, so next month we will talk about how to properly adjust your new brakes or even your old ones if they are still good and only need adjusting.
You know, every time I work on brakes or think about it, I remember one of my favorite cartoons that has even been made into posters. It pictures a rustic, old, grizzly cowboy on his horse that has fallen over a cliff. He is in the saddle pulling hard on the reins, and is yelling to his horse “Whoa you SOB, WHOA!!!”
See ya next month.