Brakes

Tiny
DAVID WAITE
  • MEMBER
  • 2004 HYUNDAI COUPE
  • 1.6L
  • FWD
  • MANUAL
  • 100,000 MILES
Just taken my car for its MOT test. It passed. On the way home the brakes werent working properly.
First press of the brake pedal there was nothing.
Quickly pressed it again, pedal was hard and brakes came on.
Then with foot pressed on pedal it started going down slowly until it was at bottom.
I had to press it again couple of times for pedal to come back up like pumping them up.
When I got home I looked under the car and there was a small puddle of what seems like brake fluid or oil.
What could have caused this? Bearing in mind there was nothing wrong with car when it went in for test and it also passed the test.

Any help appreciated.
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Saturday, May 14th, 2016 AT 3:02 PM

5 Replies

Tiny
SATURNTECH9
  • EXPERT
I really have no idea how that could have happened from just having a smog test was it? Sounds like a line might have burst. Did they rack the car up and lift it off the ground at all?
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Saturday, May 14th, 2016 AT 3:09 PM
Tiny
CARADIODOC
  • EXPERT
You have a leak. In every single case of a leaking steel line, rubber flex hose, or wheel cylinder, there was no leak one minute and it was leaking the next minute. You never know when that is going to happen.

The fact that there is a puddle underneath will make it pretty easy to locate the cause of the leak, and it is going to be related to one half of the system. You still will have some brakes even though the brake pedal goes down too far.

Also, to add to the mechanic's frustration and to yours, you will likely also need a rebuilt master cylinder, but there is often no way to know until after the leak has been fixed. Crud and corrosion build up in the lower halves of the two bores where the pistons do not normally travel. When you push the brake pedal all the way to the floor, regardless if it is from being surprised by a leak, or by improper bleeding procedures, the rubber lip seals get run over that crud and can be ripped. That results in a slowly sinking brake pedal, and that often does not show up until two or three days later. This mainly applies to a car that is more than about a year old. Fortunately most master cylinders are not terribly expensive. Many shops will automatically include the cost of a replacement in their estimate so you are covered in case it is needed. If they have your best interest at heart, they will want to replace it right away. If they are more concerned with your wallet, they may give you a repair estimate that does not include the master cylinder, so be careful if you are comparing two or more estimates from different shops. Be sure they are including the same things.

We normally do not have the best of communication skills, but the better shops will explain why the master cylinder might fail, and they will let you decide if you want to risk leaving the old one alone. That is fine as long as you understand it may fail in a short time and there is no cause to be angry with the mechanic.
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Saturday, May 14th, 2016 AT 3:14 PM
Tiny
DAVID WAITE
  • MEMBER
Thanks to both of you for your quick reply. In relation to saturntech9 question yes it was lifted off the ground. The MOT in England is an all round check of the cars strength and safety so it is a thorough check of almost everything except engine. While car is in the air he turned the wheels and shook them which I suppose if its to see if there is any unwanted movement in the wheel. With that and the testing of all break pipes I can see how this may cause a leaking pipe. It was just so frustrating to take a car in with no problem and get it back with hardly any brakes and a leak.
I don nott know if this could make a difference, but he replaced the exhaust system while it was there. Thanks also to CARADIODOC for your thorough answer. It was a big help in explaining the problem as well as calming me down from blaming the mechanic. Thank you! :)
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Saturday, May 14th, 2016 AT 4:19 PM
Tiny
SATURNTECH9
  • EXPERT
Can you call the guy and tell them what happened and see what they say?
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Sunday, May 15th, 2016 AT 12:42 PM
Tiny
RENEE
  • ADMIN
Nice work Saturntech9 and Caradiodoc! Great answers.
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Wednesday, May 18th, 2016 AT 4:13 PM

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