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What is the melting point of copper brake pipe?
speedyxjs - 8/12/09 at 09:01 PM

My brake pipes are made from 3/16" copper pipe but due to the positioning of the M/C, one of the front brake pipe outlets runs just over an inch from the exhaust.

I have covered the exhaust in four layers of exhaust wrap and when i ran it for a minute or so this evening, the (wrapped) exhaust got almost too hot to touch but the brake pipe was still cold.

Will this be ok do you think? The last thing i want is for the pipe to melt and fluid spill on it but there really isnt any other option.

I was also thinking about wrapping the brake pipe in some kind of heat reflective material if i can find some.


flak monkey - 8/12/09 at 09:03 PM

I would worry more about boiling the brake fluid than harm to the pipe.

The pipe will easily stand it (the melting point is approx 1100degC IIRC for pure copper).

But you will find the fluid will boil at about 200degC

David


dinosaurjuice - 8/12/09 at 09:03 PM

the fluid will boil before the pipe melts.

edit: too slow

[Edited on 8/12/09 by dinosaurjuice]


speedyxjs - 8/12/09 at 09:11 PM

Ok, how likely is it that the fluid will boil then due to the exhaust heat?


ReMan - 8/12/09 at 09:17 PM

Very possible.
Not good to have them that close


speedyxjs - 8/12/09 at 09:28 PM

Bugger

My last resort is to use a t piece to split the other front pipe and put a screw in that one but that will mean re bleeding the brakes.

Does anyone have any other suggestions before i do this? (cant move the M/C up as the chassis is in the way)


dave r - 8/12/09 at 09:32 PM

better to re-bleed the brakes than hit the wall at speed, cos your brake pedal hit the floor!


aitch - 8/12/09 at 09:44 PM

too ht to touch may only be 70 deg c
then the heat has to radiate to the brake pipe, meanwhile heat is conducting away from the pipe

i'd doubt you have a problem here but move it and bleed for your own peace of mind

aitch


blakep82 - 8/12/09 at 09:47 PM

heat shield between them, but not touching either?


ashg - 8/12/09 at 11:00 PM

if its over an inch away it will be absolutly fine. there is only 8mm between my exhaust manifold and chassis rail even with the exhaust got up to glowing red i can still touch the chassis rail after. my exhaust isnt wrapped


Chippy - 8/12/09 at 11:16 PM

I agree with Blake, if your worried, (I wouldn't be), then just put an ally heat shield between them. Cheers Ray


02GF74 - 9/12/09 at 08:02 AM

the fuild will boil before the pipe melts then the pipe will soften as it head towards melting point.

one inch is very close though. you could try insulating it - but still need to allow a gap fro engine movement. .... plus you need to ask youself what will SVA man say?

perhaps it is easier now to sort it than when it is fully built?

which part of the exhaust is it - the manifold or down pipes?

alternative is to move the master cylinder and re-do the chassis rails.

a pain but it will be worth it in the end.


speedyxjs - 9/12/09 at 08:35 AM

Its the downpipe. Hopefully i will be able to get a new vid of it running today and will try to get a thermometer down there to check the temp. I think if it is too hot, i will just plug it and put a T piece in the other front pipe.


Findlay234 - 9/12/09 at 08:47 AM

Ive got immense experience in redoing my possible mistakes from younger days building the car. Even before taking it to my first test I re did a few things that I wasnt happy with. The trade off is time-vs-tools-vs-money. I still had a lack of time and tools but I work now and therefore had the money to do proper jobs on those areas I felt I hadnt given enough attention.

Id say if youre near IVA then possibly put in an ally shield and take to IVA see what the inspector thinks. If you are far from IVA then change it, if its something youre not happy with then why risk the failure at IVA or failed brakes when driving for a possible issue that you had already picked up.

Cheers
Fin


speedyxjs - 9/12/09 at 12:27 PM

Well, iv been out and had a closer look. It seems it is less than 1" so i will do the t piece idea at the weekend and use the bolt that will block the hole to hold an ali heatshield for the rest of the MC.

Cheers for all the help guys