Full brake line replacement

Post by RobX » Subscribing Member » Wed May 09, 2018 10:32 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 112
Hi,
I just took a good look at the brake lines on my camper rebuild project and decided it would be a good idea to replace them before I put the floor down. :) I've seen full kits from Automec like this one, and also DIY kits like this on eBay. Bit of a price difference... So I wonder: how hard is it to flare your own brake lines? Is the remarkably cheap DIY kit the right one for me? The Haynes manual says the lines are steel, not copper. Naturally I'll need some tools but for that price difference, it's quite a tool budget. I'd really appreciate the thoughts of someone experienced in this.

Re: Full brake line replacement

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Post by VDUB384 » Club admin » Thu May 10, 2018 7:29 am
Joined: Wed Sep 12, 2012 9:01 am
Posts: 1340
The brake pipe your best to use is copper/nickel although you can use copper you can buy a cheapish brake pipe flaring kit that will do the job but they don't give you the same flare you get with a more expensive kit so best checkout brake flaring kits.
Dave
Whilst good maintainece is the best prevention"If its not broken don't fix it."
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Re: Full brake line replacement

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Post by Phil Bradshaw » Club admin » Thu May 10, 2018 1:36 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3587
Kits may or may not fit or may be incomplete (e.g. no front brake bridge pipes). DiY pipes copying what has come off the van usually are best.

As Dave says copper and cupro-nickel are the easiest for flaring and shaping and his point about flare quality is worth heeding: sometimes a rough flare just won't seal and another pipe will have to be made up if cutting off a flare makes it too short.

Downside for copper and cupro-nickel is differential corrosion of ferrous components that pipes are connected to. Copper liner of traditional steel brake pipes comes to mind...

Copper brake pipe in particular MUST be secured against vibration to prevent fatigue failure. Similar applies to cupro-nickel which is more resilient, almost on a par with steel in this respect, but it is not as stiff as steel so longer runs may vibrate which is bad for any pipe.

On CFs the pipes to the master cylinder and rear brake load apportioning valve (when fitted) may need additional support, e.g. clip pipes together so that they don't vibrate when tapped.

For tube nuts steel will be better than brass - less likely to cross-thread or strip - but will corrode unless protected (e.g. slobber over with water resistant grease every B service).

EDIT

It is important that metric standard pipe nuts, hydraulic hoses and bleed screws are not used because these can be inadvertently screwed into Imperial threads in brake cylinders and connectors but the thread engagement will be very weak and cannot provide an adequate seal. (GM Service Training manuals).

CFs should have 3/8-inch UNF brake unions ('B') but always check in case components with M10 threads ('A') have been fitted: it happens...
(3/8-inch UNF nut will bind in M10 thread.)

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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Full brake line replacement

Post by RobX » Subscribing Member » Thu May 10, 2018 9:27 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 112
Thanks, guys - much appreciated. I've definitely got imperial (and from the rust: probably original!) unions, and it looks it's the dual circuit layout. Is there any functional reason why there is a join about two-thirds of the way to the rear brakes? Could this be replaced with a continuous pipe?

Re: Full brake line replacement

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Post by Phil Bradshaw » Club admin » Thu May 10, 2018 11:02 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3587
The junction makes life easier when working from underneath especially on short wheelbase van models with b-all room above the fuel tank for threading pipe through even with the tank straps as slack as they will go.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Full brake line replacement

Post by RobX » Subscribing Member » Fri May 11, 2018 12:25 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 112
Taking another look last night, I can see the sense in that - it all looks so easy in an empty ladder chassis..! I've ordered this (3/16" brake line with a modified male-female ratio of 3/8" UNF unions), a couple of in-line unions and this. That gives me this weekend to find my pipe cutting and bending tools which I know are in the garage somewhere...
Last edited by RobX on Sat Jun 09, 2018 2:07 pm, edited 2 times in total.

Re: Full brake line replacement

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Post by Phil Bradshaw » Club admin » Fri May 11, 2018 6:03 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3587
Draper flaring tool needs some practice to get right but it works well enough with copper and cupro-nickel tube. Supporting the clamp bar vertical in a vice can make life a lot easier.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Full brake line replacement

Post by RobX » Subscribing Member » Mon May 14, 2018 4:54 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 112
Luckily, I have a vice (maybe more than one, but one of them is the one you mean!) I've got the long brake line out now. I thought I'd need to remove it all the way up to the master cylinder and for a while there I was wondering about taking the engine out as the lines run past it... but a second look at the Haynes manual showed there's a union I hadn't come across yet, just in front of the gearbox cross member. No need to jack a CF up to get under it - and leftover fake grass are just the thing for sliding around on your back.

A question though - the brake line to the rear left drum looks a bit odd:
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Should the line run in that convenient looking groove on top of the diff, or is it supposed to kind of track around the back like that?

Re: Full brake line replacement

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Post by Phil Bradshaw » Club admin » Mon May 14, 2018 5:20 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3587
Rear axle pipes on a CF350 with original metal clips long gone apart from the one under one of the bolts on the rear cover and with extra support close to the cylinders for cupro-nickel tube; insulators are 3/16-inch bore hose split along its length.

Pipe runs left and right should be to the rear of the axle to avoid crush against the (missing) bump rubber on the chassis if the leaf spring breaks but with auxiliary coil springs this isn't possible.

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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Full brake line replacement

Post by RobX » Subscribing Member » Mon May 14, 2018 6:00 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 112
Fantastic, Phil - thank you! I only had 50% success removing the kind-of-P-clips that held the line on: is there any issue with drilling new holes for self-tapping screws?

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