If you’ve been following along the past few posts, I’ve been detailing some of the potential things you’ll come across when putting your “barn find” or field fresh car back on the road after it’s been sitting for a long time. Once you have the vehicle running and moving under its own power you’ll surely want to drive it around your property to see what else it needs. The big thing that may kill the fun is the lack of brakes. In my particular case the front brakes were partially seized on and the brake pedal just went to the floor. I decided to completely disassemble the system and show how to go through the brakes on your classic car.
The first thing you should do is to check to see IF you even have any brake system pressure. Give the brake pedal a couple good stomps with your foot. In most cases your foot will go right to the floor, but if you’re lucky the pedal may have some resistance. If it has resistance, is it solid, or does the brake pedal feel “spongy” or slowly drop as you put pressure on it? If either of those happen you may have air in your system or a leak somewhere. In my case I had wheels that were partially seized on and no brake pedal pressure at all.
My vehicle; a 1952 Chevy Styleline has a single circuit brake master cylinder where the front and rear brakes are all on the same circuit and you lose ALL brakes even if a leak occurs in the opposite corner. This means you don’t get much of a second chance if the seals in the master cylinder go bad. Therefore I decided to replace the master cylinder all together. You’ll probably have to swap some parts from your old master cylinder or pedal to the new master cylinder, so don’t toss it in the trash right away! In my case I had to swap the pedal arm and some other rotating pieces. Once I had the master cylinder together I hit it with a coat of Brake Gray Paint to seal the exterior from corrosion in case I dripped brake fluid on it when filling.
Once I had the new master cylinder bolted in place I wanted to make sure that my brake lines weren’t clogged or stopped up with corrosion. I first removed the fittings from each end and blew aerosol injected cleaner through each one. The cleaner worked awesome and I continued to flush each line until clean, clear fluid came out of the opposite end. This also helped show me if there were any spots on the brake lines where there may be leaks before fully pressurizing the system. Once I was sure the lines were all clear I hooked the master cylinder ends of the fittings up to the master cylinder and decided to work on each corner.
The first thing in a brake system that goes bad from sitting is the flexible rubber brake lines. These dry out and crack and while they may hold brake fluid, they’re a ticking time bomb waiting to explode (or implode) and cause a leak or a soft brake pedal. Bend each line 90 degrees and check to see if you see any cracking in the rubber that opens up. If you see any major cracking, it’s time to replace those lines. I would also go over all of the hard lines under the car and make sure there isn’t any major corrosion or rust on the lines, especially where the mounting tabs or clamps cover the lines. Often times the lines rust under the metal tabs that hold the lines to the chassis and won’t show themselves until the lines are fully pressurized.
From here I like to take the brakes apart on each corner to make sure the pads or shoes themselves are in usable condition and also to check the movement of the calipers or wheel cylinders. In my case I knew a couple of the wheel cylinders were seized open and I decided to rebuild each cylinder. What I found was that the seals in the wheel cylinders had failed and over time had let the brake fluid seep past and when that dried it caused corrosion that locked the cylinder piston in place. I used a combination of small hooks and picks to clean in front of the piston and then I used a C-clamp to compress the pistons and brake them free. Once I cleaned the rest of the corrosion in front of the pistons out I used a blow nozzle and compressed air to force the pistons out. Make sure you aim the wheel cylinder in a bucket or box so the pistons don’t go flying across the shop!
Above you can see what I was working with, what a mess! Before I went any further I put the wheel cylinder housing in the vice and carefully broke each bleeder screw loose. Don’t be surprised if yours break off and you have to drill them out and replace with new! Now that I was down to the wheel cylinder bare housing I checked the bore for any major pitting or scarring. If you see any major pitting or scoring, you may need to get a new wheel cylinder or housing. Regardless of how clean the bores are, you should hone them out to assure the pistons will slide freely.
Honing out the bore in a wheel cylinder is much like that of an engine block cylinder. You’re trying to taking any haze, residue, or imperfections out of the bore. Wheel cylinders are a little more forgiving than an engine bore, but you can’t just take a metal file and go nuts in there, you need to be delicate. There are wheel cylinder hones available on the market, but there’s a free trick you can use to hone your cylinders using a cotter pin and a piece of 400 grit sandpaper.
Take a piece of 400 grit sandpaper and hook it into the cotter pin and then wrap it around the cotter pin. Then chock the end of the cotter pin into your drill and slowly spin the sandpaper in the cotter pin in and out of the bore of the housing until it’s smooth to the touch. I used one piece of sandpaper on the set of four housings and a little bit of Chassis clean to dissolve the heavier corrosion and residue in the housings.
After all of the brake parts were rebuilt and replaced I filled the brake system and bled each corner with the Eastwood Brake Bleeder until the car had a firm brake pedal. Once I confirmed all four brakes were adjusted correctly I took the car out for a test drive to make sure the car didn’t pull or lock up any wheel before another. I’m happy to report the car drives very nice and stops pretty well for having drum brakes all around!