Xantia S1 Ride Height and Suspension Stiffness - It's not what you think...

[Rhothgar]

I am worried

[CitroJim]

I am worried

Ditto and

[Skull]

Another thing I noticed is an intermittent fault where the brake pedals sometimes vibrates and makes a noise usually on extremely light application as though the ABS is coming on. This may well be to do with the failed ABS sensor that needs replacing. I just have visions of me needing to rebuild the brake doseur valve and don't particularly relish getting it off the car.

I’ve had the same experience for YEARS, no warning lights, sensors and ABS rings all cleaned, MoT man couldn’t read any related codes, system flushed with Hydraurincage and bled and I haven’t been able to eliminate it yet, AND to help put your mind at rest - I’ve also done the Doseur Valve (not through choice though) the vibration through the brake pedal is still there, as you say at s…low speed only.

[RichardW]

It's probably a crack in a ring, or a slightly duff sensor. You would probably need to scope the output from all 4 wheels to see which one is out of whack. It won't necessarily show a fault as it just thinks the wheel in question is locking up. I had a broken ring on my Mk2 and had to take the fuse out one morning on the way to work, as it was activating so much it was dangerous and wouldn't stop!

[Rhothgar]

I’ve had the same experience for YEARS, no warning lights, sensors and ABS rings all cleaned, MoT man couldn’t read any related codes, system flushed with Hydraurincage and bled and I haven’t been able to eliminate it yet, AND to help put your mind at rest - I’ve also done the Doseur Valve (not through choice though) the vibration through the brake pedal is still there, as you say at s…low speed only.

Cheers for that vote of confidence.

Hours of work to possibly get nowhere.

[Rhothgar]

It's probably a crack in a ring, or a slightly duff sensor. You would probably need to scope the output from all 4 wheels to see which one is out of whack. It won't necessarily show a fault as it just thinks the wheel in question is locking up. I had a broken ring on my Mk2 and had to take the fuse out one morning on the way to work, as it was activating so much it was dangerous and wouldn't stop!

Already done that Richard.

Rings all look fine but one sensor is out on ohms test at ABS ECU.

If I stop braking so gently, that will resolve the vibration. Well actually I am not actually beaming when the vibration occurs, I am just touching the pedal so maybe a faulty signal from the ABS sensor is causing it.

[Rhothgar]

Seized rear arm bearings can play havoc with the ride too - although you may be able to force it up and down, normal road undulations don't provoke enough movement.

I took a video nearly two weeks ago but have not yet uploaded it as I am sorting MOT on War Horse.

Interesting when the suspension goes down at the rear you can hear a twang sound like a coil spring pinging! Of course, it’s not equipped with coil springs…

[aerodynamica]

I had that on my S1 Xantia. Occasional abs feedback when it wasn't skidding. Never got to the bottom of it.

But buzzing at the pedal at light applications is most likely air in the supply to the brake doseur. They need to be bled very far to get all the air out.

Also, if the HP pump is drawing air some place between the LHM tank and itself you end up forever bleeding it. I had that on an XM.

A failing accumulator sphere can also feed bubbles into the brake doseur.

[Rhothgar]

Thanks Graeme. I dare say the accumulator has little life left in it. I’ll listen out for the ticks.

Interestingly the ABS light went out today if its own accord. Perhaps suggests a wiring fault and not necessarily a sensor fault. I’d bet the wire has rubbed through somewhere.

[Skull]

Interestingly the ABS light went out today of its own accord. Perhaps suggests a wiring fault and not necessarily a sensor fault. I’d bet the wire has rubbed through somewhere.

Ohh look at you… all “ABS lit up “ …I can’t get mine to even blink at me and I’ve probably had the vibrations (like ABS kicking in) for 6 years I reckon …what I wouldn’t give for an ABS light sometimes

[CitroJim]

The accumulator sphere is a good call Roger - a flat (or even flattish) one can give all sorts of odd symptoms... Not least 'funny' brakes...

[Rhothgar]

Interestingly the ABS light went out today of its own accord. Perhaps suggests a wiring fault and not necessarily a sensor fault. I’d bet the wire has rubbed through somewhere.

Ohh look at you… all “ABS lit up “ …I can’t get mine to even blink at me and I’ve probably had the vibrations (like ABS kicking in) for 6 years I reckon …what I wouldn’t give for an ABS light sometimes

YOUR WISH IS MY COMMAND!

Why don't you send me your working rear nearside sensor and I'll send you my faulty one back?

Sounds like a fair swap and you, too, can live the DREAM...

[Skull]