Brake Spring mod

Toby_HDi · Unread post by **Toby_HDi** » 23 Apr 2011, 22:35

Does anyone have any info as to the dimensions of pipe needed to replace the brake pedal spring? I think 15mm is used so what length is needed?

I've got a huge amount of 15mm copper pipe left over from a recent plumbing repair (which also gave me an oppotunity to fit a tap so I now have water supply to the front of the house

)

I'm curious and just thought I'd see what the fuss is about and try what people seem to regard as 'proper' Citroen brakes.

red_dwarfers · Unread post by **red_dwarfers** » 23 Apr 2011, 22:51

Its very much an acquired thing this brake pedal mod. I did give it a go for a little while and the performance of the brakes were amazing. The trouble is that due to the pressure sensitiveness, it can be harder to gradually brake so its certainly a summer only mod!

I would measure my bit of pipe but its been 'filed away' somewhere

Deanxm · Unread post by **Deanxm** » 23 Apr 2011, 22:58

i did wonder about this, you see my xm runs the same size discs and pads as the Activa, same callipers too, in fact the activa is wearing a spare xm calliper, the bake valves must be the same and yet the activa brakes are savage and the xm ones feel kind of numb at low speeds, i wonder if there is more difference than just a spring ruining the feel in the Activa brake linkage?

also noticed the brake valve on the Activa hisses when i apply the brakes, the xm one is silent

D

Toby_HDi · Unread post by **Toby_HDi** » 23 Apr 2011, 23:02

Mine hisses too, when you release the pedal a minute amount. Mine also seem to oscillate a bit, probably air though.

Of course, my set up is slightly different to yours Dean, the S2 Activa got the bigger 288mm discs and larger calipers.

Saying that - and disregarding the fact the Coupé's brakes need servicing - the Activa brakes are better. It will be interesting to compare the Activa's brakes to the Coupé's 4-pot Brembo calipers and 305mm discs once they are done.

DickieG · Unread post by **DickieG** » 24 Apr 2011, 09:12

Use 15mm pipe and cut it to the same length as the spring around 1 1/2" IIRC.

The biggest problem for me with the spring in place is that the degree of pressure applied to the pedal is not accurately reflected in brake performance in a liniar form. So having initially applied the brakes gently should greater braking effort be required, the additional pressure applied to the brake pedal is taken up by compressing the spring and rubber bung located inside the spring resulting in no increase in brake performance/retardation until the pedal is pressed much further resulting in a loss of smoothness and wasted braking distance which I believe to be potentially dangerous.

Whenever I've bought a Xantia the very first thing I do when I get the car home is remove the brake pedal spring as I hate having unpredicable brakes.

Deanxm · Unread post by **Deanxm** » 24 Apr 2011, 09:16

The problem i found when i first set foot in a Xantia (and so my first experience of this spring) is the brake pedal seemed to pulse, almost like the spring was making my foot bounce around on the pedal which in turn made it feel like there was something wrong with the hydraulics.

I know what /kev is saying but you do get used to having proper brakes

D

citronut · Unread post by **citronut** » 24 Apr 2011, 10:36

the only way to sample pure hydraulic citroen brakes is get an earlier citroen (D, CX, G, ),

a pulsing pedel is usualy down to air in the brake circuit and nout to do with the spring,

although the spring might exaggerate the effect,

regards malcolm

f00lzz · Unread post by **f00lzz** » 24 Apr 2011, 11:57

Surely for 'insurance purposes' this constitutes a modification to the braking system!!!!

Unread post by **CitroJim** » 24 Apr 2011, 12:18

f00lzz wrote:Surely for 'insurance purposes' this constitutes a modification to the braking system!!!!

So, on that definition, so is replacing discs and pads with after-market items...

f00lzz · Unread post by **f00lzz** » 24 Apr 2011, 12:34

Not really Jim... the mod is not available 'off the shelf' and is not how the car was originally supplied. Don't get me wrong, my own car is modded and I think it is better.

Unread post by **CitroJim** » 24 Apr 2011, 12:45

Just playing devil's avdocate Ian....

f00lzz wrote:Don't get me wrong, my own car is modded and I think it is better.

So are mine and yes, it is...

Deanxm · Unread post by **Deanxm** » 24 Apr 2011, 14:22

How many have taken the spring out then? i have and its much, much better, in fact the spring is a mod and ive removed it

No wonder everyone said the breaks felt horrible, someolne had put a pointless spring in there

D

citronut · Unread post by **citronut** » 24 Apr 2011, 17:54

i belive they put the spring in there to pacify non hydralic citroen drivers,

to give them a spongy effect,

i still have mine in place,

regards malcolm

red_dwarfers · Unread post by **red_dwarfers** » 24 Apr 2011, 18:44

Deanxm wrote:How many have taken the spring out then?

D

I sense another poll

andmcit · Unread post by **andmcit** » 24 Apr 2011, 18:44

All of my Xants are as Citroen sold them - I'm so used to hopping from one car
to another totally different feeling one that I 'tune in' and just get on with it.
I couldn't face the task and the back breaking enormity of changing ALL the
damned spongy springs. The CX/GS barke effect is the way to go though,
no question.

I will never forget my driving test examiner being winded by the severity of
the emergency stop in my GSA...

His notepad flew out of his hands and he was struggling to recompose himself.

Just to mix things up, the immediacy and sharpness of non ABS brakes
compared to ABS on the Cx's when I used to drive both types back to back
is very noticeable - it's as if the addittion of the ABS made it all that little
bit woolier in an added spongy spring on the pedal kinda way - progress eh?