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Brake failure caused by pipe rubbing off handbrake cable
Posted: Tue Apr 24, 2012 10:07 pm
by ZilogJones
Has anyone seen this before? The handbrake cable was coming into contact (not sure exactly when this was happening) with the brake pipe (the copper one) behind the rear nearside wheel. Of course I didn't notice anything was wrong until the pipe burst open, leading to a rather
interesting drive last Sunday...
Could the pipe have got bent at some stage, or fitted incorrectly? The other side was fine, but things aren't symmetrical anyway.
Mine has rear discs and ABS with a Teves servo, if that makes much difference.
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Wed Apr 25, 2012 1:00 am
by lozz

not good,
perhaps someones Routed the handbrake cable the wrong way,and its been working against the pipe,
something ive not heard of Happening on a 406,
Copper pipe sugests to me its not an original one, so perhaps when it was replaced its been slighty too long and theyve put a bend in it to compensate for the length ,resulting it to be close to cables, Hard to guess,
glad you walked away from it tho, couid of been much worse,

Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Wed Apr 25, 2012 9:41 am
by highlander
Put braided brake lines on your car - the stainless steel braiding will help keep the brake lines safe, and has the added benefit of preventing the pipes from expanding under pressure, resulting in more pressure being applied against the discs (firmer brake pedal).
Definitely sounds like the handbrake cable has not been properly routed.
Glad you came away from that one unscathed!
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Wed Apr 25, 2012 1:38 pm
by mjb
highlander wrote:Put braided brake lines on your car - the stainless steel braiding will help keep the brake lines safe, and has the added benefit of preventing the pipes from expanding under pressure, resulting in more pressure being applied against the discs (firmer brake pedal).
Braided rubber brake hoses would be a VERY poor and incredibly expensive substitute for solid steel tubing. You'd have a hell of a time adapting the car body and fittings to accept the much wider diameter hoses and you'd be exposing yourself to severe risk of slicing a brake line where it goes through the chassis for the front wheels whereas a solid pipe has no such issues.
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Wed Apr 25, 2012 10:19 pm
by ZilogJones
lozz wrote:Copper pipe sugests to me its not an original one...
Actually I'm not sure what the broken one was but it was painted black. Are the originals steel or something? Maybe the replacement was steel too (zinc plated or something?)...
I'm not sure if the mechanic re-routed the handbrake cable or re-routed the pipe (or both) but he said they shouldn't come into contact any more - it's definitely something I'll keep an eye on anyway.
I have noticed the handbrake is a bit less useless on hills now
The way the brakes failed was a bit odd - at first I noticed when braking lightly the pedal would slowly drop to the floor, but when I braked hard it seemed to hold up fine so I didn't think there was anything seriously wrong (maybe vacuum pump playing up or something). The warning lights and beeping didn't occur until about 20 minutes later when things had got worse and I had to keep pumping the brake pedal to get anything useful out of it (lots of engine braking too). Only then did I stop, get out and notice the brake fluid dribbling out the back...
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Thu Apr 26, 2012 3:00 pm
by mjb
ZilogJones wrote:when I braked hard it seemed to hold up fine
Interesting - I'd have expected hard braking to burst the hole wide open! Glad to hear you managed to stop the thing without "impact"

Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Thu Apr 26, 2012 4:47 pm
by lozz
iwas driving a car once and all the lot went, Brakes,powersteering clutch everything,
that was one of them old Hovercraft citroens bx or sumat, wouidnt drive on of them again

that was all run on green fluid tho,
ithink most cars now are desighned so all the braking system dosent fail at once, still not good when it does tho,
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Thu Apr 26, 2012 6:06 pm
by steve_earwig
The later Citroens have loads of safety valves and stuff, not much use if the pump goes I guess...
I did notice on my D8 the l/h brake cable was rubbing on the brake pipe to the caliper in a similar way to that described so this probably is worth looking at on everyone's cars. I would say though, that it looked like it'd wear through the cable before it did anything to the pipe. I wrapped tape round it

Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Fri Apr 27, 2012 10:05 am
by highlander
mjb wrote:Braided rubber brake hoses would be a VERY poor and incredibly expensive substitute for solid steel tubing.
Ooh bugger, must've mis-read this problem. I thought this was the handbrake cable chafing against and bursting through the flexible rubber part of the piping that goes to the rear calipers (i.e. the part that people buy braided replacements for), rather than the solid fixed pipework that runs the length of the car.
Carry on

Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Mon Apr 30, 2012 1:23 pm
by leestudd30
I thought braided hoses were just for the end where it connects to the caliper, they don't replace the copper pipe that goes from end to end of the car?
Re: Brake failure caused by pipe rubbing off handbrake cable
Posted: Mon Apr 30, 2012 2:40 pm
by highlander
leestudd30 wrote:I thought braided hoses were just for the end where it connects to the caliper, they don't replace the copper pipe that goes from end to end of the car?
That's right.
I had thought that the part of the brake system that had failed was the part between the caliper and the rigid piping. However, as MJB says, the part that failed was the rigid piping.
If it had been the rubber brake hoses between the caliper and the rigid piping that had failed, I think I would have been right with my suggestion of replacing these with braided hoses and re-routing the handbrake cable correctly in order to prevent this from happening again. But since it wasn't the brake hoses that had failed, I just looked like a muppet
