Xantia brakes problem.

[Maxx]

When I apply a slow pressure to the brake pedal (for a small deceleration), I listen a vibrations coming from the braking system. Recently I replaced the disc and the pads, but the problem remain. The vibration go away when I apply more pressure to the brake pedal.
Could it depends by an incorrect pressure of hydraulic system??

[AndersDK]

How often do you hear the regulator ticking ?
The ticking interval should be at least 30seconds, if not - then your main accumulator sphere is flat, and can cause a vibrating brake pedal.
If on the other hand you find the hydraulic system all fine, then you could have a problem with a distorted wheel, or even a distorted tyre.
You DO know that new brake discs comes with a rutsprotection sprayed on, and MUST be cleaned off before use ??

[Maxx]

Dear AndersDK,
I hear the regulator ticking each 3 or 4 seconds, if the interval should be at least of 30 seconds, probably you have found the problem.
So you suggest to replace the accumulator sphere located near the pressure regulator??

[Maxx]

Dear AndersDK,
I remember that my mechanic replaced the accumulator sphere just one month ago.I'm thinking about the pressure regolator, could it be damage?? Or could it be migration of oil between the pressure lines and the return lines inside any component??
TKS Maxx

[AndersDK]

Read RichardW's very fine trobleshooting here :
http://www.andyspares.com/discussionfor ... IC_ID=8549

[Maxx]

the topic 8549 is very interest, and I read a good suggest to verify the conditions of hydraulic system of my Xantia.
But the troubleshooting are not referred at the problem that I expose initially (brake system vibrations).
TKS Maxx

[AndersDK]

OK -
As you have 3-4 seconds clicking interval - you have a problem with the accumulator sphere or the pressure regulator or a system pressure loss somewhere.
Please understand that the clicking interval *MUST* be at least 30 seconds to ensure satisfactory brakes action [8]
There is <font color="red"><i>no doubt</i></font id="red"> the fast clicking of 3-4 seconds has influence on the brakes, so please attend to this problem first !
<font color="red"><i>It's no help the accumulator was replaced</i></font id="red"> - if you still have a problem [8)]
That's why it's not simply "interesting" to read RichardW's fault tracing, it's very informative indeed !
To say it very straight :
1) find and correct the cause of the fast 3-4 seconds ticking, such you have <font color="red"><i>at least 30seconds</i></font id="red"> between ticking
2) then come back here and complain if the brakes <font color="red"><i>still does not do</i></font id="red"> what you want to [:)]

[Maxx]

I will try to replace the pressure regulator, probably the system works with an incorrect pressure value.
But I must isolate eventually loss somewhere before replace the regulator.
To do this is necessary isolate the subsystem and try to find the oil migration; I think it is not so easy. [:(][:(]

[AndersDK]

Maxx -
as your first try : replace the accumulator sphere again ! - this time make sure yourself it really is a brand new sphere [8)]
it's the cheapest and fastest option !