ZX Volcane TD - Vibration under braking

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Jimmydeath
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ZX Volcane TD - Vibration under braking

Post by Jimmydeath » 12 Dec 2001, 20:21

When braking hard, usually from speeds above 30 mph i get a vibration from the front of the car which slowly dissappears as the car slows down. I recently replaced the front disks but this did not help, any advice on other possibilites would be most welcome.
Thanks
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Dave Burns
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Post by Dave Burns » 13 Dec 2001, 01:32

On the rare occasions when I am forced to brake hard with the Xantia I can sometimes hear a humming/vibrating noise which also fades as speed is reduced, I put this down to tyre noise as I know the condition of the braking components and also the fact that the sound is not accompanied by feedback from the pedal or steering, the car stops in a straight line and normal braking does not produce any sound, only if there were such feedback or the car altered course would I investigate further, if you are getting feedback or this vibration occurs during normal braking then it needs looking into, scale build up at the inner and/or outer edges of the friction surface can cause such symptoms, also but less likely are cracked or unevenly worn discs due to quality issues.
Good luck
Dave
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Dave1
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Post by Dave1 » 13 Dec 2001, 03:13

[quote]
When braking hard, usually from speeds above 30 mph i get a vibration from the front of the car which slowly dissappears as the car slows down.
I had similar problem. If you are a "quicker" driver and use the brakes hard they do overheat, the rear discs do very little. This causes heat spots. I have fitted new ones now and problem has gone. The new discs may be warped from the start or there may be some dirt on the hub stopping them seating properly. Have you checked the swing arm buses? This may be csuing the problem.
Good luck
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Jimmydeath
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Post by Jimmydeath » 13 Dec 2001, 19:15

Hello again, thanks for the replies.
The vibration is quite strong, it can make any loose items rattle in the car and it is definately coming from the front. As I said the front discs are new and I have checked them for excessive run out with a dial gauge but they are well within tolerance. Despite the vibrations the car still brakes in a straight line with no hands on the wheel.
I shall have a look at the bushes to see if it is them.
regards
James
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Guru Meditation
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Post by Guru Meditation » 24 Jan 2003, 19:35

Thought I'd resurrect this old thread to maybe get some ideas. I don't know if 'Jimmydeath' is around anymore so I guess he won't be able to say if he ever fixed his problem or not. My earlier posts about a vibration problem I believe I have since narrowed the cause of the noise and vibration down to the nearside front of the car. I am having it up on axle stands tomorrow to get a big screw driver or pry bar to try and found out what is causing my vibration but my symptoms sound the same as what Jimmydeath was experiencing. Having given my anti roll bar drop links a good tug these seemed fine. I also gave my tie rod ends a good pull and these seemed fine on both sides but I haven't checked these 'p bushes' ie are the p bushes the ones at the back of the lower suspension arm?
Some advice on what I should expect to see/feel when I check would be good. I guess I can always compare the play in one side against play in the other. I don't think it's a gearbox or engine mount because the vibration only comes into play under braking never acceleration etc. Car always pulls away as smooth as silk etc and no noise from drive shafts on lock or anything so I'm sure it is suspension bush/bushes. What else could it be? I'll check - P-Bushes, drop links, tie rod ends. Anything else? I saw some other thread about some bolt holding the hub carrier to the suspension strut?
Any advice is deeply appreciated as although I know my cars well and I'm reasonably handy with a spanner I know that the collection of dedicated specific Citroen knowledge has the potential to save me much cash/frustration.
Thanks
Guru Meditation
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jeremy
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Post by jeremy » 24 Jan 2003, 22:45

I think if the vibration you were experiencing was caused by slack steering bushes then you would get a violent feedback through the steering wheel.
1960's Ford Cortinas and derivatives were prone to this problem when the anti-roll bar rubber bushes wore. The system being that the bar doubled up to locate the front suspension. I can clearly recall my father being lent a Corsair and this thing suddenly suffering this problem when after several hundred miles he applied the brakes hard for the first time. The effect was a very violent shaking of the steering wheel and apparently considerable problems with steering the car.
Jeremy
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Guru Meditation
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Post by Guru Meditation » 24 Jan 2003, 23:12

The vibration varies under braking from non at all to very slight vibration to quite strong vibration that is felt through the whole car the vibration is accompanied with a rythmic banging/rubbing type noise from the nearside front. When at it's worst the vibration is felt slightly through the steering ie the whole wheel will shake but it does not feel like it is emanating from the acutal steering components as the handling of the vehicle feels fine so I am suspecting either these 'p bushes' or maybe I'll get lucky and it'll just be subframe mounting bolt loose or summat (be quite worrying that would tho :-( ). I'm just wondering what else is down there in the way of bushes to fail like this? One other thing I noticed is that if I take the car over some sily traffic calming bumps the offside front goes over and sounds fine but I swear the nearside front I hear what sounds like a thump through the suspension although the ride doesn't seem to be affected really.
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jeremy
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Post by jeremy » 25 Jan 2003, 18:14

Perhaps the thump is a clue. My system of elimination for anti-roll bar problems is to see if the noise occurs when both wheels hit a bump or just one. If it is just one (ie bar working) then its the bar and its joints. I think ZX's have a lower swivel similar to those on some Renaults in which case when they fail and are really bad it feels as though the whole of the front of the car is loose when you go round a tight corner. Another possible problem is the bearing at the top of the strut which from recollection (on other cars) can produce noise over bumps. The inner wisbone bushes are the most likely to affect the steering geometry and allow sufficient wheel movement to braking which might cause shudders.
I think your next job has to be a very thouough investigation of all steering and suspension bearing bushes etc. When you get bored with that you can then move on to the subframe maounts and the engine mounts. Incidentally the engine mounts are probably well worth looking at, particularily the one at the cambelt end, My BX has apparently gone through 2 quite quickly and each time an 'Expert' has replaced it and told me they make a real difference and are responsible for this that and the other. To be honest I can't say I've noticed any difference at all.
Jeremy
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