Octavia I Brake Question

[zejdkoco1]

Hello, I drive a Skoda Octavia I from 2002. It's 2.0L petrol engine and has disk brakes on all wheels and ABS. Now I have a question, not sure if it's supposed to be like that or not, but when I brake, the pedal feels like it has two stages, a soft upper part and as I push the pedal more, half way down it becomes hard. When driving normally (in city) usually the "soft" part is enough to stop the car, but when coming to a stop from a downhill or doing a hard brake, I go past the soft part and then really need to press the pedal hard in order to stop. The first time I tried to stop the car on a downhill I almost had a crash, because it caught me off guard (when I passed my driving test). I drove several (friends') cars and none of them had brakes like this. Sorry if the post is too long, but thanks in advance.

Edited 5 July, 2017 by zejdkoco1

[mushtafa]

Sounds like you've got pads/caliper slides/caliper piston partially seized. 

I would guess the front brakes, as they account for around 75% of the braking.

 

[KenONeill]

@zejdkoco1 - @mushtafa may well be right, but this also sounds a bit like you may be running out of vacuum for the servo.

 

Testing this is fairly easy though. Last thing at night (or after going to work) run the engine for a few seconds then switch off. With the engine off, pump the brake pedal until it "goes hard" (obvious when you do it). Leave your foot on the pedal, and restart the engine. You should feel the pedal sinking a bit. Take your foot off the brake, and switch off.

 

Now leave the car for several hours. When you get back in, press the pedal lightly. If it feels much harder than when you left the car, you have a vacuum leak.

[mushtafa]

The symptoms in the original post doesn't suggest a lack of vacuum in the servo. If it was a vacuum/servo fault, the initial press of the pedal would be harder than usual, and it wouldn't feel like a 2 stage activation of the brakes

[zejdkoco1]

42 minutes ago, KenONeill said:

@zejdkoco1 - @mushtafa may well be right, but this also sounds a bit like you may be running out of vacuum for the servo.

Well, usually when I park the car, after several hours the brakes are still soft (well until it gets to the middle). I had a gut feeling it could be as the car engages the front brakes first then the rear ones (if I am correct) maybe the front brakes are assisted while the rear ones aren't? (sorry if I'm totally wrong but Im not a car person)

 

PS: I know how hard the pedal is when the car is not running, and the "lower" harder part of my pedal is not as hard, so there is still some assistance there

Edited 5 July, 2017 by zejdkoco1

[KenONeill]

@mushtafa - I don't think you understand my point. I'm not saying that the servo has failed, but that it is being exhausted faster than it can refill in a long (time) braking event.

[KenONeill]

@zejdkoco1 Rather than try to explain how car brakes work myself, I suggest you look at https://www.howacarworks.com/illustrations/dual-circuit-braking-system and follow the "how the braking system works" link.

[zejdkoco1]

@KenONeill Ok thanks for the link, but I don't think it's the vacuum loss since the pedal stays soft after several hours of use.

[KenONeill]

@zejdkoco1 - I was trying to eliminate the "cheap and clean to test" possibility first. If we have eliminated that, we do get left with the idea of the calipers sticking a bit on the guide pins.

[Jux]

Sounds like air in the brakes! Try bleeding all round first starting with the cakiper furthest from the abs pump