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Discussion Starter · #1 ·
Hello everybody!
Just discovered this forum and since I have a matiz (left hand side though) so I'm here.
I have my brakes that are very soft and btw the braking not really efficient.
When I was visiting a friend who have a garage as a neighbor, the mechanic said me that it should be 100% due to the master cylinder.
While I was thinking that the problem could rather come from the power booster since I was hearing a blowing sound.
Anyway, I didn't want to be the guy not paying attention to advice, I bought a second hand master cylinder and changed it.
I did a full bleeding (in the following order: RR, LF, LR, RF) but it did not solved the soft braking:

Then I tried to pay attention to the blowing sound, and it was coming from the left hand side of the hood.
And indeed that part of the hood where there's the ABS unit was a complete mess. All the paint gone or damaged.
I thought this should be du to the brake fluid.

And indeed, I noticed a leakage happening only when pressing the brake pedal. And I just remember that I had to complete the brake fluid a few months ago.
Here is a short clip of the leakage happening as well as some pictures: It seemed to come from those button like part (there are two of these).
Then I simply removed the ABS unit in order to see the underside and better understand (and particularly to check if it's possible to fix the leakage).
Indeed there are tiny holes on those buttons.
And just before uploading the video I was pretty sure it was leaking from those holes.
But if you pay attention to the video it seems that the brake fluid is rather leaking from the base (pointed by the orange arrow in the picture) while air is indeed leaking from the hole.

So I have a few questions:
Is the soft breaking actually caused by this obvious leakage of fluid and air?
Is it possible to repair the unit (or at least just fix it enough to not leak anymore or rather to not have my pedal soft/inefficient)?
If not, I'll try to find a second hand unit, but I heard then the bleeding will need to be done with an OBD tool. Does anyone have more information about that?

I was able to find a service manual (I can link it if necessary), but it has the brake chapter not complete and I'm not sure about that.
PS: Also on that manual it says that the bleeding should be done in that order: RR, LR, RF, LF. Could be possible that because I did not do the bleeding in that order it is still soft for that and the leakage has no consequence?

Anyway, many thanks for any comment!
Have a nice day!

Super Moderator
7,465 Posts
You need to complete your Sign-Up. Your World location was left 'blank' (possibly you are in France??) and you didnt complete your Vehicle details section ie year, variant, engine etc.
The following link is helpful reading :- Helpful Guidance Using the Forum

Note: the principle of bleeding brakes is generally start with the wheel furthest away from the brake fluid cylinder, then the second furthest away and so on finishing with the nearest to the brake fluid reservoir.
There are existing discussions on Matiz brakes in the Back Index. Use the forum Search function. There may be some useful information there worth reading.

52 Posts
Greets and welcome to the forum. As Ed states its useful to have your car info in the footer so we can be sure we are talking about the correct vehicle.

In general terms the braking system is closed. Therefore any leak will give a spongy affect on the brake pedal. It is not wise to attempt repairs on an ABS unit, much easier and more sensible to change it out (since this could save your life). Make sure to take steps to ensure no dirt gets into the connections whilst doing the change out as this can give problems later on with ruined seals. It would be sensible to do a full change of fluid at the same time (since its most probably been in there for years), and its much easer to see the bubble in the clean stuff. As you can see brake fluid is corrosive so ensure to wear safety gear and keep away from the paintwork.

Hope it helps... nice video by the way shows the issue well.
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