(1999 Ford Windstar) Not only does my front end shake when I brake hard, but I had a situation the other night where the brakes did not hold. It was a bit rainy that night. As I approached an intersection, the light turned yellow. I decided to stop (which meant I had to brake hard). The front end shook, and it felt like the brakes kept slipping. I was in the middle of the intersection when I finally stopped, but the light had already turned red, so I had to keep going. Very scary. My kids were in the car. A similar situation happened about a year ago. I was stopped at a red light, several cars back. The light turned green, I started to go, but the car ahead of me stopped. I slammed on the brakes to avoid rearending her. My brake pedal went to the floor, and the brakes did not hold, and I bumped the car ahead of me. Ended up replacing the master cylinder even though the mechanic could not identify what happened. Any advise? I'd like to have some idea before going to the mechanic.

Hello, Parts of this problem are difficult to answer. For sure, it sounds like the front Rotors are out of round. You can see it at lower speeds like 15mph to 20mph with the hands off the steering wheel; applying the brakes will have the steering wheel moving left and right by itself. This is caused by the uneven surfaces grabbing at random on the front brakes.

This is a different sensation than the ABS. A condition you describe as slippage can actually be the ABS working. It is suppose to keep the brakes from locking up by pulsing the pedal pressure. The pulsing pedal pressure is suppose to help stop you in a straight line. What you describe as a shake, is a pulse to an Engineer. The ABS system is in all cars and trucks and no different overall in operation between Brands.

What you want is a test of the ABS system done with Certified testing equipment. Not some Yo-Yo trying to do a seat -of -the- pants test on a test drive. There are Electrical parts that can be bad inside the ABS unit, and there are flow valves that can leak and give improper pressure to the brake lines. You want to go somewhere that has ABS monitoring equipment so your Van can be compared to the original specifications.

It is also possible that your sudden stop revealed some slack in the tie-rod ends. This can cause a shuddering sensation too. So if the mechanic says there are parts with too much slop in the suspension he might be right. Glad your brakes worked better this time than the last, you might want to ask around to get the test you need.

I hope my solution clarified the potential problems and fixes for you.

Reason the front end shakes is the rotors are warped. when you do go to the garage makes sure your not turning the rotors past there minimum thickness. have him check the rear brakes as well for a clean and adjust (rear drum brakes) or for there condition as well. should be a normal front brake service