has any one experienced the flaired end of ther brake pipe cracking off where it bolts into the sierra master cylinder its the top right as u look at cylinder from front of car!
only got car on rd two weeks ago and 3 days ago went out for a spin with our lass and only got ten mins away and when heavy braking from about 70mph on a twisty country lane felt the pedal dissapering to the floor !!
with a quick look round i noticed fluid coming from around the fitting in master cylinder at first i thought it just needed tightening a bit but when i wiggled pipe it just pulled out in my hand ooops
so i drove her home with no brakes just handbrake
got my flairing tool out and made a new end and every thing was fine . well today ive been for a 130 mile flat out blast to scarbourght and whitby what a day good fun had it on rev limmiter a few times in 6th lol got back home just pulling up out side my workshop and pressed pedal and its done it again!!

i have done hundreds of brake pipes befor and never had one fail the first one was already made by mk second made by me and i used a fancy syks pic flairing tool this time
could it be vibrations that are causing it!
thinking of making all the pipes again out of copper nickle pipe thats what i usualy use
can any one sugest anything ???

sounds like you've had plenty of experience making blake pipes in the past, so vibration sounds like the most likely cause. i've only drive a BEC once, it was a race car and remember it vibrated a LOT! recommend checking how your lines are secured round the master cylinder, and condiser a flexible line from the MC to the first decent mounting place you've got. kind of like the copper to flexible pipe brackets where your brake calipers are. personally i'm using flexible pipes all round on my car because of the vibration. my engine is almost solid mounted, so i recon it's going to be pretty bad for it

there are two pics in my photos brake pipe and brake pipe 1 but there too large to put on but ths the top pipe were it comes out to the right and bends forward and down.

when it hits 7k it really does vibrate but stops just befor 8 not a clue what it is thats vibrating but is annoying enough that u keep at 6k or 8k and never 7 happens in every gear at same point

hmm, looking at the photos, they shouldn't move about much at all from vibration. i was sort of expecting a big loop, and like a good 6" or so of pipe before the first clip, but that looks spot on. hmmm

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Originally posted by tootall
when it hits 7k it really does vibrate but stops just befor 8 not a clue what it is thats vibrating but is annoying enough that u keep at 6k or 8k and never 7 happens in every gear at same point

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Thanks blakep82
would u recomend copper nickle pipe its a lot harder than the stuf mk suplyed me with
and may be a pigs tail in the pipe befor it goes into master cylinder.??

i haven't worked with ridging brake pipe. like i say, i'm using all flexi braided pipes from russ bost on here.

a couple of general things which may help though.
'harder' can mean more brittle.
pigs tails are good for absorbing the vibration, but too long and it can allow it to vibrate more.
33hz is one of the good resonant frequencies. ladies love it but thats niether here nor there...

not really sure what to suggest, as everything you've got in those pictures looks alright to me. i think the vibration is doing it, but not sure on the best way to fix it. someone will have some ideas in the morning hopefully

In Canada, using copper brake pipe is illegal. Everything is steel tubed. OR go flexible everywhere?

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Originally posted by RK
In Canada, using copper brake pipe is illegal. Everything is steel tubed.

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Copper brake pipe ? ----- No major car manufacturer uses copper pipe. A few years after cars were first fitted with hydraulic brakes the problems with copper brake pipes came to light. Zinc steel bundy brake pipe was invented because copper brake pipes were fracturing.



Make up new pipes in Kunifer and put a generous radius on the bends to avoid stress concentrations and check the routing of the pipe --- the retaining clips should be far enough apart to allow for some movement but close emough to avois excess vibration of the pipes.

Could be a Faulty Batch of PIPE

This happened to my indy too, turned out to be the bulkhead flexing under braking and thus bending the pipe back and forth untill snap!
I had to make a brace that ran from the top bolt of the master cylinder bracket down to the chassis.
Get someone to pump the pedal and watch!

Could it be the clutch cable moving and hitting the brake pipe. It looks OK at rest, but may move in use / or when the engine moves!

Mike

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Copper brake pipe ? ----- No major car manufacturer uses copper pipe

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As usual British Trident is right! Make up new pipes with Kunifer. Put a bigger loop on the end to allow for flex and reinforce your bulkhead to stop the master cylinder flexing. There have been a few cars failed at SVA for that. The fact that the 2 failures are pipes from different sources rules out it being a faulty pipe batch or flaring tool.

adrian

Having had problems with mine, I would only now use steel or preferably use flexi for all the runs...

James

Another vote for cylinder to cylinder flexis.

Pedal is nice and rigid and you end up with fewer joints.

Just remember you need quite a few of the (more expensive) swivel connectors.

Matt

If it's work hardening the copper in ~100miles, Kunifer is only going to extend this period, I think you need to fix the cause of the problem... I bet the bulkhead is flexing too much.. get someone to stamp on the breaks and take a look at what is happening, short distances from the outlet to fixings will make it worse if it is flexing, as said pig tail may help...

Dan

I'd also suspect the flexing bulkhead problem. Yes copper will get metal fatigue if it's moving around all the time but why is it?!?!? My STM bulkhead is make from 5mm plate so it ain't never going to flex Drilling the holes for the MCs sure wasn't fun though....

5mm!!! eek, they've beefed that up over time. I remember seeing one that had something like 1.5mm ali (yes it flexed the bulkhead, hence a rod was added to support it!)

Mine is 1.2mm steel bulkhead + 1.5mm folded steel on the pedal box bolted together.

[Edited on 8/6/09 by MikeR]

the pipe has not been changed is same pipe just cut off and new end made its just getting shorter so it could be a dodgy batch of pipe
the bulk head does not flex it is a spec r not the same bulk head as the old indy that flexs im going to make new pipes all round out of kunifer i think
car has done around 400 miles in 2 n half weeks but did 130 miles in one day and really did push car. red line every gear hard braking etc and second pipe end broke on way home in the 130 miles trip
oh well il sort it this week put some softer springs on tonight got rid of the 275lb springs and but 175lb on not been out to try it yet but it actualy has movement on the front suspention now lol

the pipe has not been changed is same pipe just cut off and new end made its just getting shorter so it could be a dodgy batch of pipe
the bulk head does not flex it is a spec r not the same bulk head as the old indy that flexs im going to make new pipes all round out of kunifer i think
car has done around 400 miles in 2 n half weeks but did 130 miles in one day and really did push car. red line every gear hard braking etc and second pipe end broke on way home in the 130 miles trip
oh well il sort it this week put some softer springs on tonight got rid of the 275lb springs and but 175lb on not been out to try it yet but it actualy has movement on the front suspention now lol