I already mentioned gas, brake fluid, and a leaking strut, but I forgot about water. Don't laugh. That has come up before when a car sits just right in the rain and water gets in the well behind the rear wheel. There's a drain hole for that but they often get blocked with leaves, or the drain hole is not at the lowest point until you park a certain way. The clue is water will evaporate and leave no trace behind. Obviously you'd smell gas. That would leave a stain when it evaporates. Oil from a strut will be just inside a tire, ... Less than a few inches from it, and brake fluid could be anywhere in that area, but only brake fluid will run down the sidewall of the tire.
A strut can leak slowly for a long time and is not really a safety issue except for reduced handling. Brake fluid is a bigger concern. If a wheel cylinder is seeping brake fluid, you'll get away with that for a little while, but eventually air will get sucked into that port in the master cylinder and cause a mushy brake pedal, and the red warning light will turn on. If you can't get the car inspected soon, look at the fluid level in the master cylinder, then see if it drops over the next few days. Most Fords have a plastic reservoir that you can see through. If yours does, make a mark on the side with a marker or piece of tape, then compare the level later. If the level is real low, (on any car), it either means there's a leak that must be addressed or the front brake pads are worn and ready to be replaced. In the second case, you can add a little fluid but don't fill the reservoir. Part of the brake pad replacement procedure involves brake fluid being pushed back up into the reservoir. Then it will be full again. If you fill it before that service, the extra fluid will run out, make a mess, and it can eat paint off the body if it isn't washed off right away.
If you add brake fluid, be sure it's from a clean and sealed container, and be absolutely sure to not get any type of petroleum product like engine oil, power steering fluid, or transmission fluid in there. Most mechanics wash their hands first to be sure they don't even get fingerprint grease in there.
Tuesday, May 20th, 2014 AT 8:14 PM