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Discussion Starter #1
While the car engine is on and you are stationary, can you push the brake pedal all the way down to the ground? I can and I'm curious if this is normal? Seem's a bit too slack for me.
 

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Discussion Starter #3
But after I turn the engine off and press the brake a few times (to get rid of the vacuum braking), the brake pedal becomes extremely tight. It won't even budge 1 or 2 cm's even when pressing it quite hard. Wouldn't this imply that there isn't any air in the pipes?

If some people could just try it the next time you go for a drive and let me know that would be great. Just remember Chazza wanted to know how far the brake pedal is supposed to go if you push it down hard (but not too hard).
 

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Something is wrong. Seeing as how it is your breaking system involved here, I would get it looked at before someone gets hurt or killed.
 

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Zettai Unmei Mokushiroku
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Originally posted by Chazza
But after I turn the engine off and press the brake a few times (to get rid of the vacuum braking), the brake pedal becomes extremely tight. It won't even budge 1 or 2 cm's even when pressing it quite hard. Wouldn't this imply that there isn't any air in the pipes?=
You can pump it a few times because the brakes are made to work for a short period of time even if the car suddenly shuts off while in motion, so you don't get into an accident from the stiff pedal that occurs after a few pumps (A LOT more effort required to slow down the car). The reason the pedal gets stiff is because the power brake system has no leftover pressure to use. That means that you're basically working with a manual brake system, where you need to push much harder to get the brakes to clamp down (you're creating the brake pressure on the brakes with your foot at this point, not the power brake system). All of this is perfectly normal.
 

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It shouldn't go to the floor. This could mean air in the lines, or possibly a small leak (very bad.). When there is air in the brake lines, the pedal tends to be soft on the first application and get successively harder in subsequent applications. A good test is to press the brake a few times with the engine running. When your engine is off, you lose power brakes after a few pushes, so that would artificially make it look like there was air in the line. That's why it is important to do this test with the engine running. To check for a small leak, push the pedal in hard and hold it with a constant force. If the pedal starts sinking, there's a leak!

In case you're interested, the reason you lose power brakes after a few applications when the engine is off is because power brakes run off the vacuum pressure created by the engine. When you turn the engine off, there is a remaining reserve of low pressure (vacuum) air for the brakes, but this gets "used up" when you press the brake pedal a couple of times. When you start it up again, your brake pedal should get softer again.
 

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Discussion Starter #8
If I take the car to Toyota to get the brake fluid changed, will this likely fix the problem (assuming its just air in the brake fluid)? I think my brake fluid needs a change soon anyway, so two birds with one stone maybe...
 

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Discussion Starter #9
marcus_GTS said:
To check for a small leak, push the pedal in hard and hold it with a constant force. If the pedal starts sinking, there's a leak!
I'll try this test tomorrow...So just push it about half way down and see if it starts to sink with the same amount of pressure applied?
 

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Chazza said:
I'll try this test tomorrow...So just push it about half way down and see if it starts to sink with the same amount of pressure applied?
Yes, do this test.

If you pump the brakes rapidly you will compress the air and eventually get a relatively firm pedal.

A pedal that slowly (or quickly) sinks to the floor with constant pressure is a sign of a leak, either internal or external.

More than likely it's a failed master cylinder (internal leak). There are rubber o-rings in there and they can allow flid past them, instead of building pressure.

On a related note, have you done any work to the brake system recently? Maybe removed the calipers for painting, done a clutch job (it shares the brake fluid), installed stainless lines, etc.

Scott
 

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Discussion Starter #11
autxr said:
On a related note, have you done any work to the brake system recently? Maybe removed the calipers for painting, done a clutch job (it shares the brake fluid), installed stainless lines, etc.


Nope I bought the car used about 3 months ago and the brake pedal felt a little soft compared to my old car, which is why I asked. It has only 42,000 Km's on it.
 
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