My Activa has a spring and is quite hard, moves about 20mm. Having got round to removing the plunger yet but intend to.
My brakes have the symptons described and I was about to invoke a Hydraflush to try and remove some of that middle travel deadness. I might try this first.
I don't agree with Citroen using a spring to gain a more "normal" pedal feel, other than to sell more cars, but I am gald the "half-tennis ball" pedal of Cits of yore has gone. That was just silly!
Terrible Xantia brakes
Moderator: RichardW
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fastandfurryous
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- x 4
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by macaroni</i>
I don't agree with Citroen using a spring to gain a more "normal" pedal feel, other than to sell more cars, but I am gald the "half-tennis ball" pedal of Cits of yore has gone. That was just silly!
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
How else do you explain the introduction of a device which has the sole function to increase brake pedal travel?
The old brake system where you actually pressed the dosieur valve was brilliant. You simply have to open your mind to the fact that the way most car manufacturers do something might not necessarily be the best way to do something.
I don't agree with Citroen using a spring to gain a more "normal" pedal feel, other than to sell more cars, but I am gald the "half-tennis ball" pedal of Cits of yore has gone. That was just silly!
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
How else do you explain the introduction of a device which has the sole function to increase brake pedal travel?
The old brake system where you actually pressed the dosieur valve was brilliant. You simply have to open your mind to the fact that the way most car manufacturers do something might not necessarily be the best way to do something.
Well I have just effected this mod and it is fantastic! It really adds to the fingertip control feel that rest of the car has. ie steering, power delivery. The brakes always felt at odds with the big torque at low revs and light steering, needing a big shove to get any braking effort. Now the progression is almost telepathic.
Marvellous - well done to whoever thought of this first.
Marvellous - well done to whoever thought of this first.
Well it's certainly not a new problem and has been raised many times.
Have a look at this thread from 2001
http://www.andyspares.com/discussionfor ... rms=brakes
and the points made by Jetfixer and myself and also the comments I got from a mechanic, quote
"the system is the same as on my BX, which has excellent brakes, except that the brake pedal has some sort of spring on it that was supposed to make the brakes gentler than on a BX."
Unfortunately, I never tried the "getting rid of the silly spring thing" because we got a 2000 HDi Exclusive shortly afterwards and the brakes were excellent.
Doing a search on this topic also revealed a "Modifications you have done" thread from 2003
http://www.andyspares.com/discussionfor ... tia+brakes
in which Dave Burns said
"Fetched that wappy spring out of the brake pedal pushrod, replaced it with something solid, feel them brakes"
Having read most of the posts on this topic over the last few year I have to say that the spring thing seems to be the culprit!!!
Have a look at this thread from 2001
http://www.andyspares.com/discussionfor ... rms=brakes
and the points made by Jetfixer and myself and also the comments I got from a mechanic, quote
"the system is the same as on my BX, which has excellent brakes, except that the brake pedal has some sort of spring on it that was supposed to make the brakes gentler than on a BX."
Unfortunately, I never tried the "getting rid of the silly spring thing" because we got a 2000 HDi Exclusive shortly afterwards and the brakes were excellent.
Doing a search on this topic also revealed a "Modifications you have done" thread from 2003
http://www.andyspares.com/discussionfor ... tia+brakes
in which Dave Burns said
"Fetched that wappy spring out of the brake pedal pushrod, replaced it with something solid, feel them brakes"
Having read most of the posts on this topic over the last few year I have to say that the spring thing seems to be the culprit!!!
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FrenchLeave
- Posts: 359
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Shane. Sorry, I mistakenly credited Mandrake with your idea - it was way past my beddy byes when I wrote it. Please read my last sentence as being addressed to you.
Simon (I hope you don't mind me addressing you by your first name). No, I haven't tried Shane's modification on my XM - it uses a different system which works very well for me. I therefore have to rely on theory, albeit theory supported by physical testing.
We can carry on this "Oh yes it is", "Oh no it isn't" argument 'till the cows come home and I have better things to do (like tiling the hall floor!) but I would like a last opportunity to correct a couple of your misconceptions.
1. Quote: "Until enough force is applied to make the spring start to compress, it is not in its elastic range, and therefore does not have a linear force to compression relationship. Go look it up if you don't believe me."
When any force (stress), however small, is applied to any object, that object is strained and is in its elastic range. If a fly lands on the Forth Bridge, the bridge bends. It has to in order to supply the resisting force to the weight of the fly. The amount of distortion may be too small to be measured, but bend it must.
2. Quote: "Besides, pratical springs only approach linear behaviour over a small range of operation, they are NOT linear over their entire range from unloaded to fully compressed, they are only approximately linear when the material is compressed into its elastic range. This is not the case with an untensioned coil spring. (Which is what is in this device)"
The force/separation curve for ferrous metals is virtually linear between -5% and +5%. A coil spring is just a torsion bar that is wound into a spiral to fit into a specific space requirement. At maximum compression it is strained less that 1% and is very firmly in its elasic range. If it were outide that linear range it would suffer permanent distortion, not possible under compression, but attainable under tension.
We seem to have got well away from the original idea of Shane's post, can we not agree that some people like the existing system whilst others prefer the direct system? Incidentally, if you want a book that covers this and many other subjects of materials behaviour in an eminently humourous and readable form, I recommend "The New Science of Strong Materials or Why You Don't Fall Through the Floor" by Prof J.E.Gordon. ISBN 0 1402.0920 4. It's a Pelican Original book, Last price I had was £2.50 in UK, $6.95 in Australia, sorry I don't have a price for NZ.
Regards, Derek (The old boy, balding, specs, in the cockpit of my boat "French Leave")
Simon (I hope you don't mind me addressing you by your first name). No, I haven't tried Shane's modification on my XM - it uses a different system which works very well for me. I therefore have to rely on theory, albeit theory supported by physical testing.
We can carry on this "Oh yes it is", "Oh no it isn't" argument 'till the cows come home and I have better things to do (like tiling the hall floor!) but I would like a last opportunity to correct a couple of your misconceptions.
1. Quote: "Until enough force is applied to make the spring start to compress, it is not in its elastic range, and therefore does not have a linear force to compression relationship. Go look it up if you don't believe me."
When any force (stress), however small, is applied to any object, that object is strained and is in its elastic range. If a fly lands on the Forth Bridge, the bridge bends. It has to in order to supply the resisting force to the weight of the fly. The amount of distortion may be too small to be measured, but bend it must.
2. Quote: "Besides, pratical springs only approach linear behaviour over a small range of operation, they are NOT linear over their entire range from unloaded to fully compressed, they are only approximately linear when the material is compressed into its elastic range. This is not the case with an untensioned coil spring. (Which is what is in this device)"
The force/separation curve for ferrous metals is virtually linear between -5% and +5%. A coil spring is just a torsion bar that is wound into a spiral to fit into a specific space requirement. At maximum compression it is strained less that 1% and is very firmly in its elasic range. If it were outide that linear range it would suffer permanent distortion, not possible under compression, but attainable under tension.
We seem to have got well away from the original idea of Shane's post, can we not agree that some people like the existing system whilst others prefer the direct system? Incidentally, if you want a book that covers this and many other subjects of materials behaviour in an eminently humourous and readable form, I recommend "The New Science of Strong Materials or Why You Don't Fall Through the Floor" by Prof J.E.Gordon. ISBN 0 1402.0920 4. It's a Pelican Original book, Last price I had was £2.50 in UK, $6.95 in Australia, sorry I don't have a price for NZ.
Regards, Derek (The old boy, balding, specs, in the cockpit of my boat "French Leave")
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DoubleChevron
- Posts: 622
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<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by FrenchLeave</i>
Shane. Sorry, I mistakenly credited Mandrake with your idea - it was way past my beddy byes when I wrote it. Please read my last sentence as being addressed to you.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Sorry, I can in no way take credit for finding this spring unit. I infact read about it here about 6months before removing the spring from my car and taking those pictures (though I did b!tch and moan a lot about the disgusting brakes on the car in the mean time).
To be honest the reason it took me so long to get around to doing this fix is my wife drives the Xantia, I've driven a variety of CX's/GS's/DS's for the last 13years (since I got my license). That's why I immediatly thought there was something terribly wrong with the Xantias brakes within minutes of buying the car.
I really enjoy driving and like to regulate braking to a standstill so I pull up exactly where I desire, I also let the brakes off a fraction of a second before I come to a standstill so there's not a shock put through the whole car as the suspension equalises. The Xanita allowed none of this, and I found it downright bloody scarey to control due to my severe lack of faith in it's braking system (or should I say my severe lack of control over it's braking system).
Doesn't this picture say it all:
I'm not superman, certainly my hands are that strong, and yet look at the movement my hand can generate with that spring unit. Seriously I find the fact this even exists downright dangerous, and simply cannot understand why import/safety regulations allowed this to be fitted.
seeya,
Shane L.
Shane. Sorry, I mistakenly credited Mandrake with your idea - it was way past my beddy byes when I wrote it. Please read my last sentence as being addressed to you.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Sorry, I can in no way take credit for finding this spring unit. I infact read about it here about 6months before removing the spring from my car and taking those pictures (though I did b!tch and moan a lot about the disgusting brakes on the car in the mean time).
To be honest the reason it took me so long to get around to doing this fix is my wife drives the Xantia, I've driven a variety of CX's/GS's/DS's for the last 13years (since I got my license). That's why I immediatly thought there was something terribly wrong with the Xantias brakes within minutes of buying the car.
I really enjoy driving and like to regulate braking to a standstill so I pull up exactly where I desire, I also let the brakes off a fraction of a second before I come to a standstill so there's not a shock put through the whole car as the suspension equalises. The Xanita allowed none of this, and I found it downright bloody scarey to control due to my severe lack of faith in it's braking system (or should I say my severe lack of control over it's braking system).
Doesn't this picture say it all:
I'm not superman, certainly my hands are that strong, and yet look at the movement my hand can generate with that spring unit. Seriously I find the fact this even exists downright dangerous, and simply cannot understand why import/safety regulations allowed this to be fitted.
seeya,
Shane L.
With everybody thoerising on how the spring will react to a given force, did anyone else notice the tapered rubber bit that acts on the piston assembly in addition to the spring once the unit is compressed about 30% ?,
There is definatly no way the braking force can be linear with the spring taking the first third of the travel, then being supplemented with the rubber piece being compressed, it actually creates 3 definate stages of resistance in my braking, and now i have taken apart the device, i fully understand why my brakes were so crap before, the 15mm copper pipr spring replacement has removed the 2 stage spring rubber thing and i get direct access to the valve and just 1 feel to the pedal travel whether i press it wit the weight of a feather, or the weight of an emergency stop,
Either way, the braking feel and my ability to stop in a smooth and controlled manner has increased 10 fold
There is definatly no way the braking force can be linear with the spring taking the first third of the travel, then being supplemented with the rubber piece being compressed, it actually creates 3 definate stages of resistance in my braking, and now i have taken apart the device, i fully understand why my brakes were so crap before, the 15mm copper pipr spring replacement has removed the 2 stage spring rubber thing and i get direct access to the valve and just 1 feel to the pedal travel whether i press it wit the weight of a feather, or the weight of an emergency stop,
Either way, the braking feel and my ability to stop in a smooth and controlled manner has increased 10 fold
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Panjandrum
- Posts: 197
- Joined: 08 Jun 2004, 18:46
- Location: United Kingdom
- My Cars:
Mandrake: Good qestions.
I see Macaroni is on the Activa case as well. On the underlying problem point - well if I knew what it might be I might have mentioned it - just speculating - though I see others suggesting things like dirt or gas in the blood.
As I see more of the insides of these things, I can well imagine that they could be erratic in behaviour for the reasons you suggest.
The semi-religious fervour of the opposing sides on this point is great fun.
On balance, it looks like SOME of us have Xantiae with a very unpleasant problem that can be easily remedied as suggested. Others really don't have the problem at all.
It's probably best if those who did have it don't assume the rest are insensitive idiots with clod feet who need to be shown the error of our ways:
And if those of us who don't have it stop trying to deny that it exists using theoretical physics in the absence of the experimental conditions.
I see Macaroni is on the Activa case as well. On the underlying problem point - well if I knew what it might be I might have mentioned it - just speculating - though I see others suggesting things like dirt or gas in the blood.
As I see more of the insides of these things, I can well imagine that they could be erratic in behaviour for the reasons you suggest.
The semi-religious fervour of the opposing sides on this point is great fun.
On balance, it looks like SOME of us have Xantiae with a very unpleasant problem that can be easily remedied as suggested. Others really don't have the problem at all.
It's probably best if those who did have it don't assume the rest are insensitive idiots with clod feet who need to be shown the error of our ways:
And if those of us who don't have it stop trying to deny that it exists using theoretical physics in the absence of the experimental conditions.
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Kowalski
- Posts: 2557
- Joined: 15 Oct 2003, 17:41
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- My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k
My view is that the problem shouldn't exist, its not something inherent in the system by design. Whether there is or isn't a problem, I can see that certainly a problem is perceived to exist.
If that spring causes the problems described and removing it has fixed the problem, then clearly there is or was something wrong. I wonder whether the doseur valve can either become more firm that in should or can become too soft so the spring is mismatched. Either that or the doseur or sping plunger become prone to jamming. If its the spring plunger that jams, removing it sorts out the problem. If its the doseur that has some sort of problem then clearly that needs looking into IMMEDIATELY, brakes are pretty safety critical. The interactions between the various hydraulic components are fairly complicted and lots of things can cause weird symptoms, e.g. air or dirt in the system, flat accumulators, faulty pressure regulators etc etc.
I've owned and driven 2 Xantias over 60k miles now and never suffered from this sort of problem on either car.
If that spring causes the problems described and removing it has fixed the problem, then clearly there is or was something wrong. I wonder whether the doseur valve can either become more firm that in should or can become too soft so the spring is mismatched. Either that or the doseur or sping plunger become prone to jamming. If its the spring plunger that jams, removing it sorts out the problem. If its the doseur that has some sort of problem then clearly that needs looking into IMMEDIATELY, brakes are pretty safety critical. The interactions between the various hydraulic components are fairly complicted and lots of things can cause weird symptoms, e.g. air or dirt in the system, flat accumulators, faulty pressure regulators etc etc.
I've owned and driven 2 Xantias over 60k miles now and never suffered from this sort of problem on either car.
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anybloodybody
- Posts: 18
- Joined: 07 Apr 2003, 16:28
- Location: Bristol, UK
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Could it be that drivers who like to drive fast & brake quick, prefer the spring replaced?
Whereas more sensible drivers who value xantia comfort, prefer things just as they are?
Did the pro-rallying/racing xantias have this spring I wonder?
Would the sceptics, rather than hypothesise, do a real drive test? (you can change the spring temporarily). Your findings may be interesting.
Whereas more sensible drivers who value xantia comfort, prefer things just as they are?
Did the pro-rallying/racing xantias have this spring I wonder?
Would the sceptics, rather than hypothesise, do a real drive test? (you can change the spring temporarily). Your findings may be interesting.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Kowalski</i>
If that spring causes the problems described and removing it has fixed the problem, then clearly there is or was something wrong.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Indeed. The presense of a spring [:D]
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
I wonder whether the doseur valve can either become more firm that in should or can become too soft so the spring is mismatched.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Not possible, if you study how a doseur valve works. The firmness that you feel from the pedal (without the spring of course) is not the feeling of a return spring or anything like that, it is purely feedback from the hydraulic pressure - the pressure going to the brakes is also piped back to the end of the control shaft which is arranged as a piston, and the relationship between brake line pressure and pedal force is a fixed relationship, based on the effective size of that piston.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
Either that or the doseur or sping plunger become prone to jamming.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Doseur ? No. Spring plunger ? Quite probably.
The doseur is a precision piece of hydraulic engineering with a valve that is machined to microns, and lubricated by high pressure LHM. The Spring plunger is a piece of crappy ABS plastic this is not lubricated, nor machined to any tolerance, and has no longitudinal support to ensure that it can't twist sideways or do anything other than slide smoothly, when put under force from the pedal.
Remember, one end of the unit is pressed into the pedal arm, and travels in an arc, while the other end is unsupported and has to press against the little rubber doseur valve button, which travels in a straight line, so once contact is made and you continue to press the pedal and compress the spring, the arm end of the housing is traveling in an arc, while the other end will be griping the rubber button on the doseur, with the end result being that it will try to twist the slide housing to the side, making binding of the sliding section almost inevitable.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
If its the spring plunger that jams, removing it sorts out the problem.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
I would postulate that the spring plungers ALWAYS jam and bind to a certain degree due to inherant deficiencies in their design, and replacing the spring is probably just as much about avoiding binding of the sliding section, as avoiding the non-linearity of two springs. (Lets not forget the rubber spring Mosser reminded us of)
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
If its the doseur that has some sort of problem then clearly that needs looking into IMMEDIATELY, brakes are pretty safety critical. The interactions between the various hydraulic components are fairly complicted and lots of things can cause weird symptoms, e.g. air or dirt in the system, flat accumulators, faulty pressure regulators etc etc.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Except that its clear there is no jaming or other problems with the doseur after the spring is removed - the sensitivity and feel and smoothness of the brakes is outstanding, which kind of rules out a faulty doseur.
Also worth considering is that the brake doseur is an EXTREMELY reliable piece of equipment, and in all the Citroen's I've known I've never known one to fail or even behave slightly strangely. About the only thing that ever goes wrong with them is they cause increased leakage when they get older making the suspension go down faster in non-antisink models. As far as their basic function goes - applying and regulating brake pressure accurately, they are extremely reliable.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
I've owned and driven 2 Xantias over 60k miles now and never suffered from this sort of problem on either car.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Given that there is a spring, there is nothing to say that all Xantia's have the SAME spring. Can you squeeze your one easily as shown in the picture a few posts above ? Or is it hard to squeeze ?
Regards,
Simon
If that spring causes the problems described and removing it has fixed the problem, then clearly there is or was something wrong.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Indeed. The presense of a spring [:D]
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
I wonder whether the doseur valve can either become more firm that in should or can become too soft so the spring is mismatched.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Not possible, if you study how a doseur valve works. The firmness that you feel from the pedal (without the spring of course) is not the feeling of a return spring or anything like that, it is purely feedback from the hydraulic pressure - the pressure going to the brakes is also piped back to the end of the control shaft which is arranged as a piston, and the relationship between brake line pressure and pedal force is a fixed relationship, based on the effective size of that piston.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
Either that or the doseur or sping plunger become prone to jamming.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Doseur ? No. Spring plunger ? Quite probably.
The doseur is a precision piece of hydraulic engineering with a valve that is machined to microns, and lubricated by high pressure LHM. The Spring plunger is a piece of crappy ABS plastic this is not lubricated, nor machined to any tolerance, and has no longitudinal support to ensure that it can't twist sideways or do anything other than slide smoothly, when put under force from the pedal.
Remember, one end of the unit is pressed into the pedal arm, and travels in an arc, while the other end is unsupported and has to press against the little rubber doseur valve button, which travels in a straight line, so once contact is made and you continue to press the pedal and compress the spring, the arm end of the housing is traveling in an arc, while the other end will be griping the rubber button on the doseur, with the end result being that it will try to twist the slide housing to the side, making binding of the sliding section almost inevitable.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
If its the spring plunger that jams, removing it sorts out the problem.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
I would postulate that the spring plungers ALWAYS jam and bind to a certain degree due to inherant deficiencies in their design, and replacing the spring is probably just as much about avoiding binding of the sliding section, as avoiding the non-linearity of two springs. (Lets not forget the rubber spring Mosser reminded us of)
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
If its the doseur that has some sort of problem then clearly that needs looking into IMMEDIATELY, brakes are pretty safety critical. The interactions between the various hydraulic components are fairly complicted and lots of things can cause weird symptoms, e.g. air or dirt in the system, flat accumulators, faulty pressure regulators etc etc.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Except that its clear there is no jaming or other problems with the doseur after the spring is removed - the sensitivity and feel and smoothness of the brakes is outstanding, which kind of rules out a faulty doseur.
Also worth considering is that the brake doseur is an EXTREMELY reliable piece of equipment, and in all the Citroen's I've known I've never known one to fail or even behave slightly strangely. About the only thing that ever goes wrong with them is they cause increased leakage when they get older making the suspension go down faster in non-antisink models. As far as their basic function goes - applying and regulating brake pressure accurately, they are extremely reliable.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
I've owned and driven 2 Xantias over 60k miles now and never suffered from this sort of problem on either car.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Given that there is a spring, there is nothing to say that all Xantia's have the SAME spring. Can you squeeze your one easily as shown in the picture a few posts above ? Or is it hard to squeeze ?
Regards,
Simon
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Panjandrum
- Posts: 197
- Joined: 08 Jun 2004, 18:46
- Location: United Kingdom
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I can't believe this is a matter of personal preference. Like I said before, I can go from gentle braking to solid stop, or to ABS operating, with gentle big toe pressure, totally smoothly and with no significant movement of the pedal. Of course I can heave on the pedal and get it to go to the floor, but this never happens except as an experiment. By the way, I came to the Xantia after about ten years of happy BX.
It is just not possible that my brakes behave as you describe the unmodified system here.
You've just got to believe that this is not a universal problem.
That means it is a fault, not a feature.
As a matter of interest, and probably irrelevant, if I get the pedal to the floor and release there is a dreadful asthmatic wheeze. Is this common?
It is just not possible that my brakes behave as you describe the unmodified system here.
You've just got to believe that this is not a universal problem.
That means it is a fault, not a feature.
As a matter of interest, and probably irrelevant, if I get the pedal to the floor and release there is a dreadful asthmatic wheeze. Is this common?
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Panjandrum</i>
I can't believe this is a matter of personal preference. Like I said before, I can go from gentle braking to solid stop, or to ABS operating, with gentle big toe pressure, totally smoothly and with no significant movement of the pedal. Of course I can heave on the pedal and get it to go to the floor, but this never happens except as an experiment. By the way, I came to the Xantia after about ten years of happy BX.
It is just not possible that my brakes behave as you describe the unmodified system here.
You've just got to believe that this is not a universal problem.
That means it is a fault, not a feature.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
What if Citroen changed the spring strength at some point ? Who is to say all models and years have identical springs ? A much stronger spring would work a lot better and avoid a lot of the side effects of the spring and still give a bit of pedal travel under emergency braking.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
As a matter of interest, and probably irrelevant, if I get the pedal to the floor and release there is a dreadful asthmatic wheeze. Is this common?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Yes, it's normal. It's the sudden release of the high pressure. When you fully depress the pedal you're putting 2400 psi of pressure onto the front brakes, suddenly releasing it causes a sudden flow of oil to return.
Nothing to worry about [:)]
Regards,
Simon
I can't believe this is a matter of personal preference. Like I said before, I can go from gentle braking to solid stop, or to ABS operating, with gentle big toe pressure, totally smoothly and with no significant movement of the pedal. Of course I can heave on the pedal and get it to go to the floor, but this never happens except as an experiment. By the way, I came to the Xantia after about ten years of happy BX.
It is just not possible that my brakes behave as you describe the unmodified system here.
You've just got to believe that this is not a universal problem.
That means it is a fault, not a feature.
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What if Citroen changed the spring strength at some point ? Who is to say all models and years have identical springs ? A much stronger spring would work a lot better and avoid a lot of the side effects of the spring and still give a bit of pedal travel under emergency braking.
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As a matter of interest, and probably irrelevant, if I get the pedal to the floor and release there is a dreadful asthmatic wheeze. Is this common?
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Yes, it's normal. It's the sudden release of the high pressure. When you fully depress the pedal you're putting 2400 psi of pressure onto the front brakes, suddenly releasing it causes a sudden flow of oil to return.
Nothing to worry about [:)]
Regards,
Simon