|
Last Updated: Jun 1st, 2009 - 09:34:53 |
Reader Question: Hello,
I was hoping you would be able to answer a quick question for me. My son was driving quite slowly in traffic yesterday when the person in front braked sharply, my son tried to brake but nothing happened so he pressed harder and the brakes seems to lock and he skidded into the car in front.
No one was hurt and very minimal damage was done but it really shook my son up that the brakes did not respond. Do you have any idea about why this happened and what should he do about it? He just wants an idea so when he goes to the garage he knows roughly, what he is talking about.
I would be grateful for your advice.
Thanks very much,
Tina
Hey Tina,
I am not sure what happened, or did not happen when he stepped on the brake. Silly question, but is he sure he stepped on the brake pedal and not the gas pedal?
I also own a body shop where we repair collision vehicles, and when we get a vehicle in our shop that was involved in an accident that the driver claims the brakes either did not work or did not work well enough. We thoroughly investigated the brake system to see if there is indeed a problem that should be corrected.
What we usually find is the driver panicked and either missed the brake pedal all together or stepped on the wrong pedal. He was driving excessively close to the vehicle in front of him to allow time for the brakes to fully stop the vehicle or the ABS system to take control and safely slow the vehicle down or some other driver error.
However, I am not saying your son did this. Nonetheless, what I am saying is that if the brakes have worked correctly before the accident, they seem to be working fine after the accident, and no one can duplicate the problem could this have been driver error?
Granted brakes can fail, but usually if they fail once they fail repeatedly after that, and it should be obvious that there is a problem. A few things that I have seen in my shop are:
1. A problem with the brake master cylinder - when at a stop light and steady even pressure is applied to the brake pedal the pedal will slowly sink to the floorboard. If you pump the brake pedal a few times, the problem goes away for a while but will repeat itself when steady pressure is applied to the pedal again.
2. A fluid leak of some kind (axle grease from a leaking seal, or brake fluid from a leaking caliper or wheel cylinder) on the brake pads or shoes that causes the brake shoes to slip and not stop effectively. Usually one wheel will "lock up" because it is over compensation for the wheel that is slipping and not helping with the stopping load.
3. Air in the brake system, which usually causes the brake pedal to feel spongy and soft and might take more leg pressure to stop the vehicle. This is not an intermittent problem, the air bubble will be in the system at all times, so the pedal will fee spongy all the time. To correct this problem the brake system must be "bled" of air.
4. An Anti Lock Brake Problem - Sometimes at slower speeds when making a panic stop with full leg pressure there is a slight delay in the brake system. The brakes are quickly applied, but the ABS system is takes just a split second to register the excessive pedal pressure and take action to stop the vehicle safely without locking the wheels and causing an out of control slide.
Depending on what kind of vehicle this is, and if it even has ABS brakes or not this might be how that brakes system works. My wife's mini van in a panic slow speed stop like what your son was involved in will result in a fraction of a second delay before the ABS system kicks in and makes that humming noise from the ABS pump that results with the ABS system is working correctly. This is "normal" for this Kia Sedona mini van.
I would find a vacant parking lot and try making a few slow speed and some medium speed PANIC STOPS yourself and see what happens. It would also be a good idea to have your mechanic inspects all 4-wheel brakes just to make sure the brake material is in good shape and there are no fluid leaks.
If this car has ABS your mechanic can read the on board computer system for any trouble codes that might have been stored that would indicate a problem.
Blessings,
Austin Davis
Related Topics - Brake Service - Brake Failure - ABS Brake System Problem
Car Repair Manuals
Automotive RSS Feed 
© Copyright by http://www.myhonestmechanic.com
Top of Page | Legal - Privacy Statements
break failure break service
