Anyone had hydraulics go altogether while driving?XM/XANTIA

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robbocop33
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Anyone had hydraulics go altogether while driving?XM/XANTIA

Post by robbocop33 »

It's just that i worry about my better half driving the car if something on the Hydraulic side fails,i've heard the steering goes first(Handy)then suspension then brakes,is there anything at all i can tell her in preparation for it?Its not even as handy or at hand just to yank on the handbrake on a normal car if the brakes fail:-)I mean on my turbo diesel XM just now its sitting in my mates garage with the Hydraulics having failed altogether(this happened in his driveway at rest) and it was dramatic enough at 2 mph pushing out the rear of his garage with no brakes!:-)
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Post by Stewart(oily) »

The citroen cars employ many devices to prevent catastropic consequences should some part of the system fail, should the engine stop or the pump fail pressure stored in the accumulator sphere should provide for around thirty presses of the brake, the front wheel operated handbrake is also particularly powerful and can bring the car to a stop easily, then theres the warning light which warns of low LHM level or pressure. you are probably protected far better in a citroen than in a conventionally braked/sprung car.
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Post by JohnD »

Last winter when I stayed in Spain I set off for the local supermarket, about two miles away. When I started the Xantia everything was fine. As I approached the carpark the stop light began to flicker I quickly parked and suddenly all the LHM was deposited under the car. Brakes and steering worked correctly up to the time I parked. The fault was in the front antisink valve. A later inspection of my route showed an increasing trail of fluid from an occassional drop when I started out, to a trickle as I neared the supermarket.
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Post by AndersDK »

Nothing to worry about.

The safety is by far better than in conventional cars - because you get the first warnings : STOP light, then heavy steering, then a suspension that can not keep itself up, then brakes that feels increasingly in-effective.

I'd say a woman driver that suddenly looses the servosteering in a Xantia/XM will instantly give up driving any further in that car.

Note that Citroen hydraulic cars can not be any worse/better than any other car when it comes to a burst brake line. Then you will still loose most of the brakes. But the Citroen will not loose brakes on both axles at the same time. Only one axle will be affected immediatey. Besides the hydraulic Citroens always have the mechanical hand/park brakes working on the front wheels.
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Post by Peter.N. »

Two or three years ago I had an instantanous hydraulic failure on the A38 in Devon, near Trago Mills, for those who know it, due to the crankshaft pulley disintegrating. I managed to drive the last couple of miles or so to Trago's with complete loss of power assistance to the steering, it was heavy but if you take it slowly it can be done quite safely. The suspension remained up and the brakes worked OK, until, that was, the AA man came to collect me, I volunteered to drive to the breakdown truck ramps and then found I had no brakes! Fortunately, I only ran into a flower bed, but I dont think it did badly getting me as far as it did, and had it not been parked for a couple of hours I could have probably got a lot further.
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Post by den169 »

My power steering pipe broke last week but the wife managed to drive it home with no power steering hard to steer but she managed it.
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Post by robbocop33 »

I had a feeling there would be back up devices somewhere along the line,i jusy wanted to know how they manifested themselves when there's a failure,thanks guys for the info!I can send her out on her merry way now filled with the joys of Citroen motoring,trouble is she keeps coming back lol
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Re: Anyone had hydraulics go altogether while driving?XM/XAN

Post by Mandrake »

robbocop33 wrote:It's just that i worry about my better half driving the car if something on the Hydraulic side fails,i've heard the steering goes first(Handy)then suspension then brakes,is there anything at all i can tell her in preparation for it?Its not even as handy or at hand just to yank on the handbrake on a normal car if the brakes fail:-)I mean on my turbo diesel XM just now its sitting in my mates garage with the Hydraulics having failed altogether(this happened in his driveway at rest) and it was dramatic enough at 2 mph pushing out the rear of his garage with no brakes!:-)
If you're concerned about safety during a possible hydraulic fault while driving, here are the main things to consider:

1) Make sure you have a good accumulator sphere on the regulator. A lot of people either leave accumulators until they're nearly flat or punctured before doing something about them, since they don't directly affect the ride quality they get overlooked. Same goes for the anti-sink sphere.

The accumulator is your main emergency braking source should the pump fail due to, for example, a snapped AUX belt. If you have a flat accumulator, a flat anti-sink sphere, and the belt breaks you will find yourself without brakes VERY quickly. (Sorry to contradict some of the others here, who say you are in no danger)

If your accumulator sphere is flat you will have no front brakes if the pump stops working, but on older models your rear brakes will still work as they run off the rear suspension.

HOWEVER in anti-sink models, there is an additional element of risk - as soon as you apply the brakes with a flat accumulator the main system pressure may drop below that needed to hold the anti-sink valves open, and the rear brakes can no longer run from the rear suspension - they can now only run from the anti-sink sphere, and if that is flat as well you have NO rear brakes either.

So consider your accumulator your first line defence for emergency braking, and your anti-sink sphere your second line defence. Very few people bother to maintain their anti-sink spheres as there is no directly observable symptom of them being flat in most cases, which is a slightly scary thought, and even I have to confess to not having tested/replaced the anti-sink sphere since I got my car, however I HAVE replaced the accumulator.

So in summary, in an emergency pump failure condition -

- accumulator and anti-sink both flat - no emergency brakes
- accumulator flat, anti-sink ok - rear brakes only
- accumulator ok - front and rear brakes ok regardless of anti-sink

Regassed accumulators are notorious for unexplained sudden failures, so I only ever use/recommend a new accumulator, although regassing is ok for suspension spheres.

2) Always heed the stop light. Do NOT drive off until the stop light goes out even on an anti-sink model. Even though I know better I did this myself a few days ago and gave myself a fright as I rolled out the garage, (pushed backwards by the auto) pressed the brakes, and nothing happened :oops: in the heat of the moment I didnt think to pull on the handbrake and luckily the brakes started working within a couple of metres. This is the only time I've ever done it in years of driving Citroen's, and will probably be the last too.

The stop light goes out at approximately 100 bars pressure. (compared to 170 bars normal working pressure)

If you're driving and the stop light together with the hydraulic light comes on, STOP! It could either be the pressure dropping below 100 bars which indicates the pump is no longer working, or the oil level sensor indicating not enough oil in the tank. As long as you heed the stop light and your accumulator sphere is good, you will have plenty of chance to stop safely.

3) On an anti-sink model if the pump fails the steering will get immedately heavy. Take this as a sign to pull over immediately.

So in summary:

For the person maintaining the car, make sure the accumulator sphere is given due attention, consider it just as important as a good set of brake pads. Also don't forget the anti-sink sphere if you want that second layer of insurance.

For the person driving the car: never drive off until the stop light has gone out, and always pull over if the stop light comes on while driving. Also pull over if the steering suddenly gets heavy and stays that way - that will probably happen even before the stop light comes on, depending on the cause of the problem.

Follow those guidelines and as others say you are probably a lot safer than in other types of cars. (No possibility of vapour lock, also large amounts air in the brake lines can only delay, never stop the brakes working unlike a vacuum servo system)

Regards,
Simon
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Post by fastandfurryous »

There is of course also the major safety aspect that the handbrake works on the front axle, thus, in the one-in-a-gazillion chance that you loose absolutely everything at speed, you still have the ability to stop almost as fast as you would with normal brakes.
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Post by Mandrake »

fastandfurryous wrote:There is of course also the major safety aspect that the handbrake works on the front axle, thus, in the one-in-a-gazillion chance that you loose absolutely everything at speed, you still have the ability to stop almost as fast as you would with normal brakes.
Yes, quite right, I forgot about the handbrake, so even if all the above fails you do still have the handbrake and unlike a lot of cars where the handbrake can barely hold you on a grade, most Citroen handbrakes are rather powerful, as they all work on the front discs.

I wouldn't say "almost as fast as you would with normal brakes" because you're only activating the front brakes, and only by hand, but still reasonably good, equal to about medium braking.

Older models had a seperate pair of pads for the hand brake on the front discs, but the Xantia uses the main pads and calipers.

The only problem with this is that people are not conditioned to try using the handbrake to stop in an emergency situation. Even when rolling out my garage with no foot brake, I forgot to try the handbrake. Luckily there was no-one walking past on the footpath :oops:

Regards,
Simon
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Post by jeremy »

last year i had a leak apparently to the back of the engine bay / bulkhead on my BX. it became noticeable on holiday but as it was slow i assumed it was a return pipe or the octopus and kept on topping it up - on the basis that if it was high pressure it would gush out or spray.

Came home and sent it in for its MOT thinking that the tester would offer to repair it for me and after all he had a lift which would make it easier. Imagine my surprise - it passed - no mention of anything wrong at all.

So I duly got underneath to find out what was leaking and eventually decided that the pipe between the regulator and the safety valve was somehow leaking. Its a curly one and I thought this must have work hardened and cracked - so I didn't touch it until I had another as I didn't want the car stuck down. (I stopped using the car.)

New pipe was about £20 and when I removed the old one I found that a plastic clip used to secure another pipe had chafed through the pipe.

Should this pipe fail the accumulator will simply discharge. the light will come on and safety valve will shut and you will be left with suspension for a while and back brakes (which are of course load dependant and probably rather feeble.) the hand brake will work (I have a roadtest which records one as working at 53% (0.53g) which is just over the minimum for a footbrake.)
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Post by citronut »

no but i have on my BX came back to dover from frogy france,and warning lamp came on then steering got heavy,rear susp went down,front susp went down,brakes went,so i drove it home from there to hastings no steering,suspesion or foot brake,just had hand brake no probs,my misses and son kept saying pull over and get a recovery service,but i was not going to splash out about £100 squide
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Post by nick »

A friend of my family used to go on to anyone who'd listen that after owning a BX he'd never have another Citroen because "The brakes aren't safe". He'd had the brakes fail on his BX on quite a steep hill, with as he said "no warning".
It turned out that all the time he'd owned it the accumulator sphere had been more or less flat, then the pipe from the reservoir to the pump had split, dumping most of the LHM on his drive. He had been topping the fluid up to compensate for the loss, but then thought, "whats the point, it only leaks out anyway" so didn't put any more in after that.
At the point his brakes failed he had been driving the car for several days with the STOP light permanently on, no power steering and the suspension on the bump stops, but didn't think it would matter.

Who was it who said "You can make something foolproof, but its impossible to make it idiot-proof"?!
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