binding brakes (cure and Conclusion)

casperdog2 · Unread post by **casperdog2** » 07 Aug 2009, 03:55

I asked for help off the forum about the binding brakes on my xantia est sx. I did everything that you could think of and I kept hitting a brick wall.
I bled the brakes changed the calipers, and after reading info off the forum from the year 2002. I changed the shpere on the accumulater. Thats it I thought two hundred yards and they were binding again. When I got the car home I just happend to look at the brake pedal and I lifted it up and the brakes came straight off, the return spring was u/s and the pedal was just touching the brake button and the weight of the dammed pedal was enough the put the brakes on that tiny, tiny bit, so as the brakes heated up the binding got worse, So a 30 pence spring was all it needed, I could have set it on fire after all the work and time I put into it.
So if anyboby else has binding brakes,
First check that the pedal is not touching the brake button.
check that the accumulater shpere is giving the right pressure. fast ticking change it its u/s, clean and service the brakes,

DickieG · Unread post by **DickieG** » 07 Aug 2009, 05:54

Well done for spotting that one, I can understand your thoughts of setting fire to the car, been there once or twice

citronut · Unread post by **citronut** » 07 Aug 2009, 08:50

i dont understand why the pedel touching the button should cause this, as even if the spring was/is good the plastic capsual is always laying/restting on the dozer valve button, as thats its natural state,

maybe for some reason the pedel pivot was partly seized/sticking
and liftting it up just freed it off

regards malcolm

Unread post by **CitroJim** » 07 Aug 2009, 10:26

Delighted it is resolved and that the car did not end up in a fireball

mark21td · Unread post by **mark21td** » 28 Sep 2009, 15:07

Just been serching through for info on my binding breakes,
Gues what my peddle has no spring either, so thats the first thing to do before messing with the calipers.

Search and you will find !!!

xmexclusive · Unread post by **xmexclusive** » 28 Sep 2009, 17:11

Hi All

On XM's the doseur piviot has a habit of seizing up and causing rubbing front brakes.

John

Unread post by **DHallworth** » 28 Sep 2009, 17:23

Is there any particular knack to freeing off the doseur valve on the XM's?

Need to do my 24v I think.

David.

citronut · Unread post by **citronut** » 28 Sep 2009, 19:34

John wrote
"the doseur piviot"

do you mean the brake pedel pivot as the doseur valve dose not have a pivot, as it opperates with a plundger beeing pressed by the pedel,

and the doseur valves on most hydraulic citroens are near enough identical

Mark wrote
"my binding breakes,
Gues what my peddle has no spring either, so thats the first thing to do before messing with the calipers. "

i dont belive there is any way in which the spring in the plastic plundger under the brake pedel can cause binding brakes,

because if the spring was missing and it had not been replaced by the famous piece of metal tube, the plundger would not even make contact with the doseur valve,

regards malcolm

regards malcolm

xmexclusive · Unread post by **xmexclusive** » 28 Sep 2009, 20:52

Hi David & Malcolm

The XM Doseur is mounted in the front scuttle towards the centre of the car to one side of the drive rod from the brake peddle. There is link mechanism with a pivot bolt to change the vertical rod motion into a horizontal force to operate the Doseur valve. The XM scuttle fills with all sorts of crap and is usually pretty wet as well so the link mechanism is often found to be partially seized. I seem to recall Noz reporting this problem and fix for binding brakes fairly early on in the original club-xm forum.
Sorry just not got the experience to know is this is relevant to any other PSA cars.

John

mark21td · Unread post by **mark21td** » 28 Sep 2009, 21:40

What I ment was the pedle it's self just flops up and down, surly it should have a sping to hold it up and away from the valve until you press it down.

Xaccers · Unread post by **Xaccers** » 28 Sep 2009, 22:22

The brake pedals on mine are feather light so I can't see how they'd activate the doseur just by their weight, and Jenny had the pipe mod when I first got her.

Does anyone have an exploded diagram of the valve?
Is it kept closed by hydraulic pressure or is it spring loaded?
Just thinking whatever keeps the valve closed, could that possibly weaken enabling the valve to be operated slightly by the pedal?

citronut · Unread post by **citronut** » 28 Sep 2009, 22:46

ok John i had not had any experiance of the XM's set up, but the AX has linkage to link the servo which is the oposite side of the bulk head to the pedel box, this to dose become seized and can also hold the brakes fully on locking them up,

but there is no way i can see the pedel weight can cause the brake to be on slightly on a XANT, as the the plundger on the rear of the pedel sits on the rubber cap the cab side of the doseur valve all the time

regards malcolm

Unread post by **xantia_v6** » 29 Sep 2009, 06:36

There is no spring on the xantia to hold the pedal away from the doseur valve, but I think that there must be a spring inside the valve that provides some pretension (or is it achieved by hydraulic pressure?)

This diagram (courtesy Clogzz) is a bit small, but are any of the components a spring?

I think that the original poster has a faulty doseur.

Unread post by **myglaren** » 29 Sep 2009, 06:59

Click the diagram to expand it.