Xantia Failing Brakes!

Penguin · Post by **Penguin** » 14 Apr 2008, 12:18

Just had a phone call from my wife who was in a bit of a panic saying that my newly acquired 1.9td Xantia SX was rolling down our drive when she put her foot on the clutch to start the car. THe handbrake was on and her other foot was on the brake pedal. I have recently had the lhm fluid replaced and since then the car has been sinking upon start up and taking a little while to come back up. Could our problems be linked to the fluid change? Is it possible to get an air lock? I have tried doing Citrobics and have also done a 230 mile round trip since the change, should this have cleared any potential air lock?

Any help gratefully received.

Post by **myglaren** » 14 Apr 2008, 12:29

Check the pressure bleed screw. Sounds as though it isn't properly tightened up. If it really comes loose there will be an unholy mess, apart from nothing hydraulic working.

Does the STOP light come on all the time - should do if it is losing pressure.
Handbrake is independent/mechanical though and should not be affected by any defects in the hydraulic system.

Penguin · Post by **Penguin** » 14 Apr 2008, 12:35

The stop light is only on briefly at start up and doesn't come back on again. Will check the pressure bleed screw when I get home. Thanks for your advice.

Post by **RichardW** » 14 Apr 2008, 13:12

Runaway Xantias when parked are hardly unknown - early cars were recalled to modify the handbrake to help stop it happening. Trouble is, first instinct is to hit the brake pedal, but that does little, since there is no system pressure. The only way back is to yank the handbrake on harder. You need to be aware they can run away at any time when parked, so to avoid trouble:

1. Always pull the handbrake on hard
2. Always leave in gear
3. If starting on a hill, gently dip the clutch first holding the handbrake - if it does start to run away, then just pull the handbrake on harder till it holds*

Just needs a slightly different mindset..

* If it won't hold then get the system looked at - broken cables where they flex onto the front hubs, and water ingress to the adjusting mechanism are both common causes of poor handbrake performance on Xantias.

Post by **myglaren** » 14 Apr 2008, 13:22

If the stop light is only on briefly then I would probably discount the pressure bleed screw suggestion - I would expect it to be on permanently.

The fact that you have no pressure in the braking system but no warning light is in itself a cause for concern.

Can you hear the fluid hissing when you depress the brake pedal?

I once found my Xantia in he middle of our street, blocking all the traffic.
It was VERY early in the morning so hadn't caused any problems but another half hour and I would have been shot for it.
It had rolled out of the slightly upgrade parking area. It was more likely me than a handbrake failure though.

Penguin · Post by **Penguin** » 14 Apr 2008, 13:28

Rich and Myglaren thanks for the replies. I am now a little confused(having never owned a Xantia before), should the footbrake work when parked or not?

Oh also, how would I know ifthe handbrake mod had been done or not? BTW my car is a 95 model.

Cheers again

Penguin · Post by **Penguin** » 14 Apr 2008, 13:32

myglaren wrote:If the stop light is only on briefly then I would probably discount the pressure bleed screw suggestion - I would expect it to be on permanently.

The fact that you have no pressure in the braking system but no warning light is in itself a cause for concern.

Can you hear the fluid hissing when you depress the brake pedal?

I once found my Xantia in he middle of our street, blocking all the traffic.
It was VERY early in the morning so hadn't caused any problems but another half hour and I would have been shot for it.
It had rolled out of the slightly upgrade parking area. It was more likely me than a handbrake failure though.

Sorry Myglaren probably got a bit confused here. I'm not sure whether teh stop light stayed on or not today as it was my wife using the car, and as far as I can tell, this was the first time this has happened. My reply was referring to the fact that usually it only comes on for a few seconds at start up then goes out. Sorry for the confusion

Post by **myglaren** » 14 Apr 2008, 13:46

Penguin wrote:Rich and Myglaren thanks for the replies. I am now a little confused(having never owned a Xantia before), should the footbrake work when parked or not?

Oh also, how would I know ifthe handbrake mod had been done or not? BTW my car is a 95 model.

Cheers again

The footbrake will usually work 3 times with the engine off, after that - zilch.

A fact I discovered all on my own in my first Citroen - A GS.
Running down an eight mile long hill into town, I turned the engine off, as I usually did.
The car increased speed up to 80MPH and approaching a bend I braked to slow down a little.
Didn't actually brake as the suspension had used all the pressure reserve.
Good job the handbrake was OK.
Learned a potentially fatal lesson there.

Post by **myglaren** » 14 Apr 2008, 13:47

Penguin wrote:
myglaren wrote:If the stop light is only on briefly then I would probably discount the pressure bleed screw suggestion - I would expect it to be on permanently.

The fact that you have no pressure in the braking system but no warning light is in itself a cause for concern.

Can you hear the fluid hissing when you depress the brake pedal?

I once found my Xantia in he middle of our street, blocking all the traffic.
It was VERY early in the morning so hadn't caused any problems but another half hour and I would have been shot for it.
It had rolled out of the slightly upgrade parking area. It was more likely me than a handbrake failure though.
Sorry Myglaren probably got a bit confused here. I'm not sure whether teh stop light stayed on or not today as it was my wife using the car, and as far as I can tell, this was the first time this has happened. My reply was referring to the fact that usually it only comes on for a few seconds at start up then goes out. Sorry for the confusion

No bother, I expect your wife would have told you if the STOP light was illuminated - it is pretty hard to ignore.

Penguin · Post by **Penguin** » 14 Apr 2008, 14:07

No, I don't think she would. She was in complete panic mode as the car rolled towards the gatepost, the problem for her is that, due to medical reasons, she can't pull the handbrake on too well and relies on the footbrake so, as I say PANIC!!

Thanks for the replies, I'm glad you are still around to help following your learning curve incident.

I think the handbrake issue was probably exacerbated by the fact that I had just driven 230 odd miles quite quickly and everything was nice and hot when I applied it. Having cooled it no longer gripped the disc too well. Do you think this is a reasonable asumption?

Cheers

Post by **myglaren** » 14 Apr 2008, 14:23

Penguin wrote:No, I don't think she would. She was in complete panic mode as the car rolled towards the gatepost, the problem for her is that, due to medical reasons, she can't pull the handbrake on too well and relies on the footbrake so, as I say PANIC!!

Thanks for the replies, I'm glad you are still around to help following your learning curve incident.

I think the handbrake issue was probably exacerbated by the fact that I had just driven 230 odd miles quite quickly and everything was nice and hot when I applied it. Having cooled it no longer gripped the disc too well. Do you think this is a reasonable asumption?

Cheers

This was the reason for the recall. As the discs cooled they disengaged from the pads and the car would roll away.

I believe that this only applied to the first batch of imports and was due to the relocation of the handbrake lever to accommodate our peculiarity of driving on the wrong side of the road. Your car should not be affected

Post by **myglaren** » 14 Apr 2008, 14:35

I have re-read your original post and it does seem that you are losing pressure overnight.

As the standard startup sequence is to fire up the engine, wait for the STOP light to extinguish, check the car has 'inflated' (mine was a pre-antisink model), dip the clutch, engage the gears THEN release the handbrake and the clutch, you would not expose yourself to the risk your wife experienced.

Because of your wife's particular circumstances this is apparently not an option.
You should still investigate the reasons for depressurisation but as an added safety measure park on a dead level area if at all possible to eliminate the chances of this recurring.

It looks like the anti-sink valve isn't functioning and releasing the stored fluid to the reservoir and thereby the pressure for the braking system.

If the mechanic just renewed the LHM without flushing the system, it could possibly be some debris caught in the valve. A good flush would likely fix it.

Penguin · Post by **Penguin** » 14 Apr 2008, 14:39

Thanks

jeremy · Post by **jeremy** » 14 Apr 2008, 18:54

The handbrake was originally like that on the BX which is superb and very powerful. It is actually a victim of its own sucess and in use the temptation is only to apply it very lightly - which is quite enough to stop the car rolling at traffic lights etc.

The problem is that when the discs cool they contract slightly - which - yes that's right - has the effect of releasing the pads grip on the disc - and so the car rolls away.

The modification was to replace the find ratchet with a coarser one with its first five or so teeth missing - so a good heave is now needed to apply the handbrake. So if yours has the original brake it will have a superfine ratchet which starts to click as soon as the lever is moved. If its coarse and clumsy its been modified.