I’ve seen a lot of people with brake issues- No matter what they do they just can’t get it right. Let’s go over some common mistakes:
Stock Brakes
Brakes on Bugs, Ghias, Type 3s, and Things from 1965 and on used an angled brake adjusting screw. If your car is of that year range, look at the screw carefully. The angle of the screw has to match the angle of the shoe.
It is also common to have the wrong shoes for the wrong screws. For example, let’s say you have a 64 car with a 66 transmission. You buy shoes that are for a flat screw, but the screws that are in the backing plate are angled. So now we have the correct shoes but the wrong screws. The shoes must match the screws!
Still having problems? Most people don’t know you have to back off the E-brake cables before adjusting the rear shoes. Why? The cable pulls on an arm that spreads the shoes away from the wheel cylinder. If there is any tension on the cable, the shoes will be away from the wheel cylinder. You adjust the shoes up but the wheel cylinder still has to travel to reach the shoes before pushing them. If you back the cables first, it will insure the shoes are up against the wheel cylinder. Now, adjust them and when you step on the pedal the wheel cylinder is already against the shoe. Less fluid to move means a better pedal. You can’t screw up on front brakes because there are no cables or spreader bars.
Bleeding your brakes
I am going to take some heat on this one… We’ve all been taught that you start with the wheel farthest away from the master cylinder. I only agree with this if you have a single stage master cylinder. If you have a tandem master cylinder (that came on bugs & buses1967 and newer) then you have to start with the passenger side front.
I can hear it already: “Bullshit”. Here are the facts: If you look at a tandem master, you will notice the nose (farthest away from the boot) is for the front brakes. The back of the master is for the rear brakes. So what? Think about it if you bleed the rear first, there is a good chance the pistons inside will not push far enough to get the air out of the front section. (Oh snap!)
If you’re having problems and you think it’s a bleeding issue, open a bleeder on the rear passenger side and leave it open as you bleed the fronts. This will make sure the pistons travel far enough to get the air out of the fronts. Keep in mind, 70% of your braking is in the front.
Disc Brakes
A common problem with disc brakes: No pedal unless you pump them up. Sometimes, especially if your reservoir is lower than your calipers, fluid returns. With the size of the pistons in the calipers, it takes too much fluid to move them back to the rotor. You may need a residual valve to keep the pads closer to the rotor as it keeps 2psi in the line.
Now the opposite problem, you have good pedal but the brake won’t release. This is especially common. Keep in mind calipers have no springs to return the pads. This is normally due to your flex lines being collapsed. They may look good (even new) but are bad. The master cylinder can push 600psi+ and will push fluid through the bad hose. Now the pads are against the rotor and there’s no spring to pull them back. If the fluid cannot get back through the hose at a low PSI, then the brakes stay on. Crack the bleeder and if the brake releases then it’s most likely a bad hose. This holds true for drums as well.
Master Cylinder Adjustment
This is critical. Too tight and the pistons don’t come back enough to let the fluid back into the reservoir; too loose and we are just pushing the pedal and not doing anything. If you had x-ray vision, the right adjustment is 1/16” of play before the rod pushes the piston. Chances are you probably don’t have X-ray vision, so you’ll just have to feel for this. Make sure you’re not feeling the slop in the clevis to the pedal. I use one hand on the pedal and the other to push forward on the rod to take the clevis slop out of what I am feeling.
Brakes on an Off-Road Car
I highly recommend you do not put disc brakes on the front of an off road car unless you are willing to put them all the way around with some expensive proportioning valves. Here’s why: We know that 70% or more of our braking is in the front, so why is this bad? You’re in your Baja Bug, going down a dirt hill, and there’s a turn. You realize you’re going too fast to make the corner; you hit the brakes and turn the wheel into the corner. Much to your dismay, you realize that even with the wheel turned you’re still going straight over the bluff. In the dirt, you want good rear brakes so you can slow down, but not much in the front so that you can steer it without locking up. I am a fan of using rear disc brakes in this case.
“Steve, my car is on/off road, so now what?” I would run rear disc brakes and stock drums in the front. Run the front metal brake lines through a proportioning valve that you can screw down. This way, when you’re on the highway, you open the proportioning valve to have front and rear brakes. When you jump off the pavement, I would screw the valve down shutting off most of the front brakes so I can steer in dirt. For the non-racer, this works well.