Terrible Xantia brakes

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DoubleChevron
Posts: 622
Joined: 22 Sep 2003, 18:06

Terrible Xantia brakes

Post by DoubleChevron »

Hi Guys,
since I first got the Xantia last year and complained about the cr@ppy brakes on this forum I have known exactly what was wrong.
You see gentle stops are good, full blown crash stops are good however in every other way the brakes are worst than sh!tfull. They are the worst brakes I've ever tried to use. Gimme 2cv or Traction drum brakes anyday. At least I can regulate them with any sort of control. In the xantia this is how moderate braking. Push gently ... a little harder ... a little harder ... **** STOP YOU B@STARD followed by a full on crash stop.
What Citroen in there infinate wizdom have done is fit a spring between the brake pedal. Yes I can't believe anyone would be stupid. You see they wanted the brakes to "feel" spongy and soft like all other cars (yes after 50years of brilliant high pressure brakes the are vastly supperior to everyone elses braking system they do insane things like this).
You can simply pull the plastic spring unit out with your fingers:
Image
If I squeeze it this is what your doing when you try and apply the cars brakes:
Image
Fortunatly the fix really does take only 5minutes:
pull the plastic ring back:
Image
The bit circled in yellow is the gap in the plastic split washer, now simply pull both halves this plastic off:
Image
I went out and looked in my bucket of nuts 'n' bolts and found this metal tube. I think it's from a CX or DS somewhere, but I can't remember. All I needed to do was grind it off about 0.5mm.
Image
Then is was a simple matter of re-assembling it.
The brakes in the Xantia are now brilliant. How much improved they are can NOT be described in words. They would be on par with early DS brakes for lightness and responsiveness. So if your not happy with your Xantias brake, the fix is extremely simple. The brakes are now absolutely bloody brilliant
seeya,
Shane L.
dan.2cv
Posts: 245
Joined: 01 Apr 2003, 04:13

Post by dan.2cv »

it looks as though you have cut the tube to the height of the spring's resting length, surely this will restrict the movement of the pedal in such a way that you can't push the pedal down far enough and thus restrict the amount of pressure you can apply to the brakes?
If this is the case surely this mod is bloody dangerous!?
nick
Posts: 1079
Joined: 14 Mar 2001, 02:49

Post by nick »

The spring arrangement is what links the pedal to the button on the doseur valve. The only reason the pedal needs to be pushed down as far as it normally does is because of the spring. If the spring is replaced with a solid object then the brakes will still operate fully, just further up the pedal's travel.
NiSk
Posts: 1422
Joined: 24 Jan 2002, 21:11
x 1

Post by NiSk »

This is a well known mod on the LHD XM, which also has the "silly spring". Replacement of the spring with a tube or even a 10mm nut hughly improves the braking reaction time.
I say LHD since I know that the RHD XM has a pretty weird braking arrangement, but as said, over here in Sweden it's common practice to replace the spring.
//NiSk
nick
Posts: 1079
Joined: 14 Mar 2001, 02:49

Post by nick »

I've been thinking of carrying out this mod to my Xantia for a while, I really hate the "springy brake pedal effect" that this thing causes!
Stempy
Posts: 1626
Joined: 27 Feb 2004, 00:21

Post by Stempy »

Did this a while back, works a treat. Such a simple job to do and such a huge improvement. Anyone who dislikes the Xant brakes and does this will kick themselves for not doing it sooner.
alexx
Posts: 462
Joined: 19 Nov 2002, 03:42

Post by alexx »

Unfortunately, it's a different arangement on LHD Xantias...
dan.2cv
Posts: 245
Joined: 01 Apr 2003, 04:13

Post by dan.2cv »

Ah, I see, I thought it was just a damper as opposed to a (damped) operating rod.
DoubleChevron
Posts: 622
Joined: 22 Sep 2003, 18:06

Post by DoubleChevron »

Hi Guys,
let me explain a little better. As you all know the DS Citroens had 'button' brakes, ie: there was just a little button on the floor that looked like a dimmer switch. This was your brakes.
Would you believe that is all the brakes still are ?? You see with the GS/CX/BX/Xantia all they have done is mounted a pedal above this button that just flops around doing nothing unless you push the pedal onto the brake button.
Anyone that has driven a DS/GS/BX/CX knows they have brilliant brakes. The only difference between them and the Xantia ?? The spring tube above is mounted BETWEEN the brake pedal and brake button. Yes it appears stupidity has no bounds. Rather than apply braking force to stop the car you just compressing this stupidly dangerous spring.
So if you want your Xantia brakes to feel dramatically (infact just like DS/GS/CX/BX brakes) all you need to do is is remove the spring as described.
seeya,
Shane L.
mike_zr7
Posts: 23
Joined: 25 Jan 2004, 02:52

Post by mike_zr7 »

My xantia brake pedal sits very low in relation to the accelerator and clutch pedals. Brakes seem OK, and have recently replaced front and rear discs and pads and bled brakes, but cannot get the brake pedal up any higher.Do you think it would be ok to replace the plastic spring unit with a slightly longer metal spacer.
nick
Posts: 1079
Joined: 14 Mar 2001, 02:49

Post by nick »

It is perfectly normal for Xantia brake pedals to be very low in relation to the others, but I can't see it would cause any problems fitting a longer spacer if you want the pedal to be higher.
john alexander
Posts: 360
Joined: 12 Apr 2004, 00:43

Post by john alexander »

Is it just as easy as that,is there anything that can break off when you pull out the plastic tube and how hard is it to get back in. Regards John.
xantiav6
Posts: 121
Joined: 06 Jun 2004, 22:31
x 3

Post by xantiav6 »

I tried this yesterday, and it really is that easy. It took a minute or two to dislodge the assembly with my fingers, but no tools were required.
For a spring replacement, I used a stack of washers (12mm ID, 22mm OD, 4mm thick). These were actually Jaguar V12 head stud washers.
Note that the pictures do not show that there is a rubber spring inside the steel spring. This is why you need to use tubing or washers and not a solid rod.
With the tubing/washers in place the inner rubber spring will have no effect. I do wonder if this is asking for trouble, as the rubber spring is designed to take the force of emergency braking, and the parts the steel spring rest on are not.
Regarding the effectiveness of this modification, I think it depends on your driving style. I don't really notice much difference, as the same force on the pedal still produces the same braking force. The pedal movement is less.
User avatar
AndersDK
Posts: 6060
Joined: 21 Feb 2003, 05:56
x 1

Post by AndersDK »

Earlier models (GS/CX/BX) uses the exacty same type brake doseur valve - with no rubber or steel spring between pedal and the doseur valve rubber button.
There are no reports on damaged doseur valve units on these models because of emergency braking.
The reason why this subject may confuse many Xantia owners is, that they have not tried how exact the same brakes system works in a BX or CX.
The usual brake pedal travel on any standard car is approx 100mm.
On a BX/CX you have approx 20mm.
Admittently this gives quite a few screaming brake actions for the first timer. But it is amazing how fast you adapt to this - and enjoy a very safe feeling with the brakes.
DoubleChevron
Posts: 622
Joined: 22 Sep 2003, 18:06

Post by DoubleChevron »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by xantiav6</i>

I tried this yesterday, and it really is that easy. It took a minute or two to dislodge the assembly with my fingers, but no tools were required.
For a spring replacement, I used a stack of washers (12mm ID, 22mm OD, 4mm thick). These were actually Jaguar V12 head stud washers.
Note that the pictures do not show that there is a rubber spring inside the steel spring. This is why you need to use tubing or washers and not a solid rod.
With the tubing/washers in place the inner rubber spring will have no effect. I do wonder if this is asking for trouble, as the rubber spring is designed to take the force of emergency braking, and the parts the steel spring rest on are not.
Regarding the effectiveness of this modification, I think it depends on your driving style. I don't really notice much difference, as the same force on the pedal still produces the same braking force. The pedal movement is less.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
It makes me wonder if they didn't have different grades of springs. Maybe some were stronger. The difference with my car was dramatic, possibly your car had a MUCH stronger spring so the difference isn't as noticable.
seeya,
Shane L.