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What's wrong with my car's brakes?
June 12, 2012 4:25 PM   Subscribe

My brake pedal sinks when I turn on my car. And my brake lights flicker. What could be the problem?

I have a 97 Ford Taurus. I bled the brakes last summer because I was having problems with the pressure on the pedal. Now all of a sudden, when I stop the car - my brake lights turn on and quickly turn off when I sink the pedal to the floor. Whenever my car is turned off, the pedal is really firm and the brake lights turn on when I apply pressure to it. I have no idea what the problem could be.

There have been also times where if I needed to brake quickly, my ABS light would quickly turn on and turn off after 3 seconds.

Can anyone help me out? Thanks
posted by morning_television to Travel & Transportation (15 answers total)
 
Have you checked the brake fluid level?
posted by COD at 4:35 PM on June 12, 2012 [1 favorite]


Yea, brake fluid is leveled. No signs of a leak.

Also, I've just now looked at it again and now the brake pedal isn't shifting the gears at all. I can't get it out of park.
posted by morning_television at 4:38 PM on June 12, 2012


The master cylinder is shot?
posted by thewumpusisdead at 4:39 PM on June 12, 2012


Master cylinder?
posted by goggie at 4:40 PM on June 12, 2012


Also, I've just now looked at it again and now the brake pedal isn't shifting the gears at all. I can't get it out of park.

This leads me to believe there is a problem with the shift-lock solenoid. That may be unrelated to your other issues, though.
posted by InsanePenguin at 4:57 PM on June 12, 2012


It's normal for the brake pedal to soften a bit when you switch the car on. The car has power brakes, which only have power when the engine is running.

Otherwise...

Now all of a sudden, when I stop the car - my brake lights turn on and quickly turn off...

How can you tell? You can't see the brake lights from the driver's seat.

...when I sink the pedal to the floor.

You shouldn't be able to sink the pedal to the floor.
posted by jon1270 at 5:00 PM on June 12, 2012


I forgot to add, don't mess around with brake problems. I do regular maintenance on my brakes (pads, rotors, etc.,) but if something unexpected ever happens with my brakes, the car goes straight to the mechanic. I don't mind paying to have it checked out professionally, because brakes are damn important.
posted by InsanePenguin at 5:02 PM on June 12, 2012


Of course I can't see the brake lights from the driver's seat - that's why I had someone actually look for me. The brake lights turn on when I lightly apply pressure but then when I continue to push down further, they shut off.

The pedal sinks down further into the floor but it never actually touches it. The pressure is still there, so if I take my foot off of the pedal - it slowly goes back up.

I agree, I don't mess around with brake problems either. I'm definitely taking it somewhere but I can't help but want to find how BIG of a brake problem this is.
posted by morning_television at 5:08 PM on June 12, 2012


go to a mecanic. Have the breaks bled out. You have air in your brake line. Dangerous! Don't drive the vehicle, have it towed. It's to risky. My father was a mecanic and I have had the same problem before.
posted by brittaincrowe at 5:29 PM on June 12, 2012


The brakes dropping is normal - if you hold pressure on the pedal and start the car, the pedal should sink a bit. However, you should find that if you pump the brakes slowly after the engine is stopped again (even a period after the engine has stopped) that the pedal will move less and get progressively firmer.

I am wondering if you have several issues here:

1: Gear shifting issue and brake light issue - dodgy brake light switch. The transmission will not let you shift until it knows you have your foot on the brake, which uses the same switch that the lights use. No pressure on the pedal sensed = no lights and no shifting available to you.

2: Brake potential issue. This is hard to get a handle on with some of your descriptions as they are vague. It is possible that the brake light issue is causing you to look at the brake system in a way that you don't normally and so are seeing normal usage as an 'issue'. If the pedal pressure when driving seems fine and the pedal pumps up to firm when engine is off and then sinks when it is restarted, then you maybe don't have an issue. It is possible that you have a vacuum leak which means that the brake system doesn't retain any 'power' in its assist vacuum reservoir over time (when the engine is not replenishing it) but this would need more investigation.

You certainly have a brake light switch issue. This will likely be cheap. Get your brakes looked at (just a road test may be enough) when you get that done and you may be ok. It's kind of hard to tell from what you are posting.
posted by Brockles at 5:41 PM on June 12, 2012


I agree with you. Mostly because I just looked at the brake light switch and noticed something. The switch has two wires running into it, one is intact while the other has broken loose. I think this will definitely solve the brake light issue but will it solve the shifting gear issue?

Also, how would I go about re-soldering that wire? It's cramped right underneath the dash and I barely have room to move around that much. Not sure if anyone is familiar with brake light switches but is there a way to completely take it off? I followed the wires but it went too far back
posted by morning_television at 6:01 PM on June 12, 2012


Sorry, re-read your response and yes - the brake light switch controls the shifting as well
posted by morning_television at 6:02 PM on June 12, 2012


how would I go about re-soldering that wire

That depends on where it is broken. If it has snapped off from the side of a moulded switch you're likely scuppered. If it is broken in the middle of the wire then just a wire join is possible. A new switch shouldn't be too much and is likely replaceable yourself and there should be a plug for it further into the dash.

If you can't easily repair the one you have I'd look up online for a manual or just buy a new switch and work out from the length of connecting wire on it where the plug must be. Shouldn't be too hard. It will either bolt or clip into the bracket holding the pedal, is my guess.
posted by Brockles at 6:46 PM on June 12, 2012


Or if it's using one of those quick-connect spade terminals that are common on cars you can probably just strip the end of the broken wire and crimp on a new connector.
posted by hattifattener at 8:08 PM on June 12, 2012


The switch looks pretty inexpensive [no idea how complex install is], and the wiring appears to attach via spades. You should be able to crimp a new spade connector on per hattifattener pretty easily.
posted by chazlarson at 9:03 AM on June 13, 2012


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