How to Check Your Brake Lines
If the fluid level in your master cylinder remains full, you don’t need to check your brake lines. However, if you’re losing brake fluid, you need to check for a leak in the wheel cylinders or the brake lines.
The easiest way to check brake lines is to put the vehicle up on a hydraulic hoist, raise it over your head, walk under it, and examine the lines as they lead from the hood area to each wheel. Leaks may be coming from holes in the lines where the steel lines become rubber ones or where the brake lines connect with the wheel cylinders.
If you don’t have access to a hoist — maybe at the auto repair class at your local school or at a friendly garage — you have to jack up your vehicle, one end at a time, and get down on the ground with a flashlight or work light to look at your lines.
To check your brake lines, do the following:
Check carefully along the brake lines.
Wetness and streaks of dried fluid are signs of trouble.
If you see rust spots on your lines, gently sand them off.
Also look for thin places under those spots that may turn into holes before long.
Feel the rubber parts of the brake lines.
You are looking for signs that the rubber is becoming sticky, soft, spongy, or worn.
Your brake lines should last the life of your vehicle. If they look very bad, have a professional take a look at them and tell you whether they should be replaced. If the vehicle is fairly new and the brake lines look very bad, go back to the dealership and ask them to replace the lines free of charge.
Look at the inner surfaces of your tires.
Leaking wheel cylinders are indicated by dripping.