Hi,

My car stood still for a couple of weeks beacause i can't drive it at the moment (surgury on my leg) but my brother drove it today.

But now the brake pedal is to soft. You (almost) can push it to the bottem.
With the engine of and several times of braking the pedal gets a little harder but not as it used to be.
After starting the engine with a little pressure on the brakepedal it drops slightly further.

Does anyone know this problem?
broken maincylinder or something like that.

Got Barchetta 254mmx20mm brakes at the front and barchetta 240mmx11mm rears.

it did work only the pedal was a bit softer after placing the barchetta rear calipers.

Greetz Dennis

Didn't you have an issue with weeping nipples :devil: That was sorted wasn't it?

I'd just give everything a visual check first and re-bleed. If air was trapped in the pipework initially, after weeks of standing it may have worked its way around the system.

the dropping pedal on start means your servo is working which is good

A complete flush will only cost a few Euro's and may sort it out before worrying about master cylinder and the like!

Kristian

Don't press too hard on the pedal, you can turn the seals.

Did you get the big barchetta rear calipers, if so they need a lot more fluid than a pair of wheel cylinders

Cheers

D

as i said it worked before. I did the rears at christmas 2006 and untill now they did work only the pedal was a bit softer but now it's worthless.
Last time the car was oké and it only stood still for 6 weeks.

kritip: Didn't you have an issue with weeping nipples That was sorted wasn't it?

Click to expand...

Huh?


If it's the brakeservo or maincylinder i want to try to get one (main+ servo) of the Barchetta.
This one should be better than the cinq one with the big brakes.

Check the flexible brake pipes,
i had this for ages on a Peugeot 306 that i had, I replaced everything and then the last thing i changed were the flexible pipes to the front wheels and it sorted the problem.
You could not see it leaking but it was letting in air.

Cheers Nick

From what I can remember from the discussion about your upgrades you don't have any flex hoses on the rear calipers. So I would start looking for the problem here - maybe simply the stiff connections pushed the caliper out (and so the cylinder in) over the time. And now, because of the stiffness, the caliper travels more in/out on each cycle. Just a theory... Or the other way round - it has problems moving and hence the problem. Then following rallycinq's suggestion, maybe the master cylinder is simply too small for your system. If it is then you are playing with your life mate, so get it fixed.

Cheers,

Woj

Believe me the brakelines at the back are not the problem.
I did asked it at the company were they came from and he said you could bend them a lot of time in sharp corners. The only movement now is less than a millimeter. And it has a wide corner.

Maincylinder is to small i know that why the pedal movemant increased after placing the back calipers. (also at the front the movement was a bit more)
But i did drove it for more than 5 months without any problems exept a little longer pedal movement.

After the last time nothing was wrong untill last week when we did took it for a drive.

Can't find any leaks and the fluid is still at level.
When I'm holding the pedal on pressure it don't drop further.

Maybe it is air but I really think there is a leak in the maincylinder which causes the longer movement.

At the moment I am trying to put a barchetta brakeservo and maincylinder in it.
Brake servo is a few cm bigger and the shaft about 1cm longer tot connect the pedal. With a 0.5 spacer between servo and car it fits almost straight in it. Only needed a bit more space at the wheel side. Stop!! Hammer time
The shaft was 99% aligned with the pedal.

It was hard to get it in so I hope it will work. It's a brakeservo from a junkyard and the maincylinder was really bad so i bought another one.

In the manual they don't say to losen both of the gearbox brackets but I really need to do that to get a bit space to unmount the original.

Tomorrow I'll put the maincilinder in it and connect the brakelines. Maybe a refill.

interesting idea...will like to see how this turns out

would the master cylinder bolt onto the cein servo do you think?

Kristian

kritip said:

interesting idea...will like to see how this turns out

would the master cylinder bolt onto the cein servo do you think?

Kristian

Click to expand...

Nope unfortuanlly not. I had that in mind to.

See pics.


Barchetta main.


Cinq servo.


Barchetta + main in cinq.

Brake servo is about 2.5/3cm bigger in diameter.

Brake servo is working only still pedal to the metal.
Probably still air in it. Tomorrow we put the system under pressure to get the air out.

Do you have a picture of the new one installed?

Kristian

Last photo. above.

The brake lines are long enough to bend them in position.
So no new brakelines with this mod.

Only problem is the mounting plate of the pressureregulators.
One hole fits the other one don't.
At the moment it hits the gearboxlever at the back. Tomorrow I'll bend in a bit to get some clearance.

Btw, there is a fluitreservoir who can place direct on the maincylinder. I'll wil try to get one.

After a second time bleeding the system the pedal is hard.

It really brakes much easier than before.
And the pedal is hard again.
:worship:

Small problem today.
If the brakes gets warmer they lock the wheels without breaking.
Probably the clearance between pedal and servo is to small and the Main Brake cylinder can't release the oil. After a few minutes they work again.

The original brake servo is adjustable but I don't know if the barchetta is also adjustable.

Otherwise I'll make the hole at the pedal a bit bigger.

Problem solved by making the pedal clearance a bit bigger at the servo/padal site.

btw are those things to eliminate blocking for the rears adjustable?
Brakes at the back are a bit weak.
(240mm discs.)

Brake bias valve. Maybe try fitting one from a car equipped with discs all round, for example a Punto GT.

The bias valve has to be fairly strong in its action as drums as more likely to to lock up before a disc will. Though I found the brake distribution to be spot on on the cars I have converted when brake balance has been measured for MOT.

these bits, ja. i thought they were adjsutable on the cento? i've never tried though, i thihnk my brake balance is bob on

I don't think they are on a normal cento, but are on the cento van model not in the uk.....not 100% but i think i read that in another thread.

KRistian

arent they connected to the rear suspension arms, and adjust bias depending on suspension compression in the rear?>