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1. Brake pedal vibration or Shaking steering wheel when braking 2. Brake pedal goes to the floor
Bad Vibrations 1. Brake pedal vibration or Shaking steering wheel when braking Dear Professor: I have a '96 Chrysler Concorde with a problem. When I drive around 50mph and tap the brake pedal, my steering wheel begins to shake. What could this be? Don't you hate when that happens? This concern is not exclusive to Chrysler owners. Many other vehicle owners share similar concerns. The symptoms are typically a shaking steering wheel or a pulsating pedal when the brakes are applied. In either case, the problem can be serious if it impairs your ability to control the vehicle. - Gil Dear Gil: These symptoms may be caused by loose suspension, steering or brake components. In most cases, the problem isn't a loose part, but a brake rotor or two with excessive lateral runout. Occasionally, the problem is an out of round brake drum. All this really means is that the brake pads or shoes are unevenly applied. The result is that the steering wheel and/or brake pedal tend to bite back. Excessive runout can be caused by overheating the brakes or by a number of small mechanical deviations added together. The problem is usually corrected by machining the rotors or drums, preferably with an on-car brake lathe. Your technician will also want to make sure that any contributing factors, such as misadjusted brakes or bent parts, are corrected at the same time. Now go, and drive safely. ©2000 carcrisis Uh oh 2. Brake pedal goes to the floor Dear
Professor: Ten days ago I
replaced my front brake pads and rotors on my 1993 Chevy van.
Since then my brake pedal drops under normal conditions.
It seems okay as I start to brake, but the longer I push on the
pedal; the lower the pedal seems to go.
Any suggestions? – Dave Dear
Dave: I suggest you
increase your life insurance coverage. Your wife is going to need it if you keep playing chicken
with your trick brake pedal. Secondly,
this is what you get for working on your own brakes to save a buck.
Brake jobs are why repair shops were invented!
Not only did you waste your weekend and bust your knuckles, but you
still have a problem with your brakes.
It also sounds like your recent brake work may have created this
quandary. Care
must be taken when working on brake systems to keep the brake pedal from
traveling outside its normal range of motion.
When this happens, seals inside the brake master cylinder are
pushed into dangerous places and can lose their birthright. It’s
like the real baby seals that you see on nature shows.
Just let one of those pups slide into the ocean and BAM!
It’s Orca time. I’m
talking chicken of the sea. It may be too late for the seals, but it’s not too late for you. Check your brake fluid level to make sure you don’t have a major external leak. If the reservoir is still full, your master cylinder may be leaking internally. Check a shop manual for details. ©2001 carcrisis Petroleum + Brakes = Trouble Dear
Professor: My
Cherokee’s brake pedal feels soft and goes to the floor when I step on
the brakes. It will stop, but
I have to step on the pedal a few times.
My mechanic said the brakes failed due to power steering fluid
being introduced into the brake system.
Could this be true? I
did accidentally add the wrong fluid, but what harm could that cause? –
Tom C. Dear
Tom: Although petroleum based fluid was used in some older European cars, modern brake systems require glycol or silicone based fluids. You don’t have to worry about ingredients though, just use the brake fluid (DOT 3, DOT 5, etc.) suggested by your owner’s manual. Of the several properties brake fluid must have, one is that it must not deteriorate the metal and rubber parts it contacts. The problem with p/s fluid is that it attacks rubber components, causing them to swell, distort and eventually leak. If you added just a little bit of p/s fluid to your brake fluid reservoir, immediately realized your mistake and suctioned it out, you might not have a problem. However, using your brakes after adding the fluid pushed it beyond the master cylinder, contaminating the entire hydraulic system. Like digested pond scum, once brake systems are contaminated, the effects are soon realized. The safest solution is to replace and/or overhaul all hydraulic brake parts that contain rubber (i.e.: calipers, wheel cylinders, master cylinder, hoses). I’ve seen people try to get away with replacing just the master cylinder, but they soon became believers. The petroleum residue left in those systems continued to eat away at cups and seals, effectively ruining the brakes. After replacing the appropriate parts, the system should be flushed with denatured alcohol, or at least several cans of brake fluid. Become familiar with your car’s essential fluid requirements to avoid repeating this mistake. Your owner’s manual will show you what goes where and some cars even use color-coded fluid fill caps to help keep things straight. After all, you don’t want to inadvertently add windshield washer fluid to your engine oil. Now that would really make you sick. © 2001 carcrisis © 2001 carcrisis.com (all images and articles on this site are trademark protected and may not be used without permission)
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