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Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 10:29 pm
by tomstickland
I've failed the MOT on corroded rear brake lines.
I've had a look and it's the main pipe from the front of the car and the two metal pipes that come off the T piece by the diff.
It looks like it'll be a right arse of a job to do - access to the unions is difficult with the subframe in the way. Plus I'd have to use string to measure the pipe length and have Copper tube flared up.
I'm thinking that maybe I'll just pay the garage the £150 they quoted for the job and let them do it on their 4 post lift.
Am I being a wimp?
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 10:58 pm
by stuartgallafant
mate, bite there hand off for £150!!!
im currently in the process of doing mine
i removed my rear beam to change all the bushes and ended replacing EVERYTHING for new at the rear end!! fuel tank came out and all sorts!!
the brake pipe that comes from the front to the rear is £45 on its own (from BMW) the smaller ones are about £4. then you have to bend them into shape, which is a really, really, really, really sh!t job!!
while they're there, get them to change the hoses too
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:02 pm
by tomstickland
I replaced the hoses when I did the subframe. I wish I'd done the pipes too.
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:04 pm
by stuartgallafant
silly boy!!!
thats what made me do it! i took it out n thought "f*ck taking that out again!!!" so out came the tank aswell and now i've spent over nearly £400 on brand new parts... ouch
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:04 pm
by murran
no you not really being a wimp. it is an arse to do, especially on the floor if your not dropping the rear beam off to do the rear beam bushes too.
if you do do it yourself give all the unions a good squirt of wd40 a few times in the days leading up to the job and just chop the pipes next to the unions and use a socket on the unions. its also possible to unbolt the t-piece off the car...... same unbolting the pipes off the rear flexis, take the oppertunity to replace the flexis, pipe and securing springs too, back to the calipers then you can just chop and cut and remove them insted of struggling undoing things under the car.
when building them back up..... dont use copper pipe, use cunifer stuff. its a copper/nickel alloy and much better.
dont buy the pipes from bmw! you can buy a flaring tool, a bag of unions and a roll of brake pipe for £40........
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:05 pm
by eko
Im in the same boat as Stu.Removed the rear beam and tank and decided to do the pipes as a matter of caution,mine werent actually that bad.
I made up my own pipes using Kunifer.In total ive spent about £60 which has repiped the whole car including all brake pipes,all fuel pipes and even the clutch pipe on the bulkhead.
pain in the ass of a job so id say £150 is a fair price.
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:07 pm
by eko
oh and ive bought a set of braided lines to so in total ive spent about £100 to replumb the car.
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:12 pm
by stuartgallafant
murran wrote:dont buy the pipes from bmw! you can buy a flaring tool, a bag of unions and a roll of brake pipe for £40........
motherf*cker!!! oh well. I've probably only spent about £60 on brake pipes in total anyway, and i didnt have to flare them!
Tony, where did you get your braided hoses?
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:14 pm
by tomstickland
You're leading me astray now.
Where did you buy the pipe and flaring tools from?
"Think" automotive?
What diameter is the pipe and what thread are the unions?
Is this the size?
English cars are almost always plumbed in 3/16" tubing, which utilizes standard 3/8-24 UNF thread swivel nuts.
What's this?
Brake lines should always be fabricated from Bundy tubing having a wall thickness of 0.028" minimum
I've received a lot of correspondence on this point. The pipe in question is called "Kunifer" or "90-10 Copper-Nickel". It's being used in lots of new cars of European manufacture; Volvo has used it since 1976. There are a couple of good online articles about it - here and here. (These links have a tendency to break - search under
www.copper.org.) If you read through them, you'll see the the yield strength is good but lower, and the expansion rate under pressure is good but higher, than Bundy tubing, so I stand by my original statement - this stuff doesn't belong in a race car. It is probably perfectly fine for a street car.
http://www.dimebank.com/BrakePlumbing.html
If I can make my own pipes then I reckon that I can do this job.
I'll probably lower the entire subframe, not that bad a job once I get on with it. Classic case of a bit more work upfront to make the whole job a bit easier.
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:24 pm
by eko
Stu got my pipes from here,3 sets posted worked out at £47 each set

Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:25 pm
by tomstickland
From where? Zone shop?
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:26 pm
by eko
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:32 pm
by murran
http://www.machinemart.co.uk/shop/searc ... ool/page/1
http://www.vehicle-wiring-products.eu/V ... brakes.php
tho any car spares shop should be able to supply you with a 25 foot roll of cunifer 3/16ths pipe and some 10mmx1 short male unions you need.......... cheaper than the prices on that link above too!

Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 10, 2008 11:38 pm
by tomstickland
Thanks, useful info.
Yes, I looked at Machine Mart. I'll probably go to my local independant tool shop (Bell Tools).
So the E30 uses 10mm threads?
I wouldn't advise using Teflon braided lines, even though I have in the past. Their service life is about 5 years.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 2:12 pm
by jaistanley
tomstickland wrote: I wouldn't advise using Teflon braided lines, even though I have in the past. Their service life is about 5 years.
Does this include the type that are protected by a plastic overcoat? The ones without have dust and dirt ingress which can ruin the inner teflon pipe, but the protected type shouldn't should they?
I'm planing to re-pipe the rear arms on my car with a single line, from a banjo at the caliper to the T piece on the E30. This is 'cos I'm using ZM arms and calipers which have a different layout to E30 ones.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 2:26 pm
by tomstickland
I don't know TBH. I've read in a few places that there can be issues. Having said that, std rubber ones don't last forever, so if you keep an eye on them probably still worth using them.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 3:42 pm
by tomstickland
I've just phoned up Pirtek in Gloucester and they stock Bundy tubing.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 3:53 pm
by jaistanley
Forgive my ignorance.... Bundy tubing? Wossat?
edit: Steel pipe.. Gottit.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 4:01 pm
by tomstickland
No, there's a copper variety. Er, I think.
Off to take another look.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 4:02 pm
by tomstickland

That's Bundy tubing. I think it's just another Copper alloy.
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 11, 2008 11:29 pm
by kipper
just done mine....well i did the front ones...started to the rear ones and said "aye right"
put it next door to another garage and listened to him swear for a few hours lol...cost 140 quid but worth having to do it lol

Re: Replacing rear brake lines (metal pipes).
Posted: Thu Jun 12, 2008 11:24 pm
by tomstickland
I've bought all the bits to do it myself.
Going to jack the car up and remove the subframe in order to get access.
Re: Replacing rear brake lines (metal pipes).
Posted: Fri Jun 13, 2008 7:38 pm
by cass1_5503
your brave just done mine it was a real nightmare, took absolutely ages with the help of 2 others. its not difficult just awkward and when bolts are seized and not to mention when a bush gets stuck in the body of the car youll be wishing you payed the 150 quid hope i havent put you off

keep us updated
Re: Replacing rear brake lines (metal pipes).
Posted: Fri Jun 13, 2008 7:55 pm
by o22ie
anything that takes more than 5 mins to fix, or involves getting dirty, take to the garage.............
that was me for 25 years.... now at 42 (and with help from the zone for a good few months) im actually tackling jobs myself...
im upto at least 30 minute jobs now

Re: Replacing rear brake lines (metal pipes).
Posted: Sat Jun 14, 2008 5:55 pm
by Andy335Touring
BMW tubing is fairly hard to bend so i used copper pipe instead
Re: Replacing rear brake lines (metal pipes).
Posted: Sat Jun 14, 2008 6:28 pm
by old_skool
The BMW steel pipe is easier to bend than Kunifer though guys. Kunifer is very hard indeed.
I bought a front to rear pipe and cut it into sections to make some more shorter OEM pipes up. Works out cheaper that way and will last another 20 years

Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 7:50 am
by B7
Dameon. This is a job I'm going to do over the winter. Figure I can take my time and "get it really right" so to speak

So you recommend the original BMW pipe but whats the best way to bend it. I've seem to remember seeing miniature pipe bending kits (small versions of the plubmers ones). What did you use mate?
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 10:09 am
by Brianmoooore
Kunifer every time! Never had any trouble bending it.
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 1:23 pm
by tomstickland
Unfortunately I've been ill this weekend, so not started the job. I took the subframe off last year, so it's all greased up nicely, so no big fears on taking it apart.
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 1:33 pm
by eko
Brianmoooore wrote:Kunifer every time! Never had any trouble bending it.
Agreed,no problem bending mine to shape.
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 2:26 pm
by cass1_5503
B7 wrote:Dameon. This is a job I'm going to do over the winter. Figure I can take my time and "get it really right" so to speak

So you recommend the original BMW pipe but whats the best way to bend it. I've seem to remember seeing miniature pipe bending kits (small versions of the plubmers ones). What did you use mate?
i used the genuine pipes didnt find them that difficult to bend by hand

plus the advantage of the genuine pipes is thee all the correct length and they are flared with the unions already on them
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 2:35 pm
by Brianmoooore
cass1_5503 wrote:the advantage of the genuine pipes is thee all the correct length
That's also the big disadvantage with them. You have to get the bends as tight as the originals, or the pipes won't be long enough. Will made in situ ones, you can be a little more generous with the tighter radii.
Re: Replacing rear brake lines (metal pipes).
Posted: Sun Jun 15, 2008 2:37 pm
by cass1_5503
Brianmoooore wrote:cass1_5503 wrote:the advantage of the genuine pipes is thee all the correct length
That's also the big disadvantage with them. You have to get the bends as tight as the originals, or the pipes won't be long enough. Will made in situ ones, you can be a little more generous with the tighter radii.
also a good point
Re: Replacing rear brake lines (metal pipes).
Posted: Tue Jun 17, 2008 5:20 pm
by tomstickland
Re: Replacing rear brake lines (metal pipes).
Posted: Wed Jun 18, 2008 3:35 pm
by tomstickland
Quick question about flaring.
I've just used the Machine Mart Clarke kit (about £20) and put single flared ends onto the pipe using the 3/16ths size.
The joins do up tight, so I assume that they're going to work properly.
I've never flared pipes before, so just checking that I've used the correct flare type.