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Login to post Forums » Grassroots Motorsports » Impart your experience with brake line unions/splices, please

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Sept. 26, 2011 12:50 p.m. Duke SuperDork

So, my Grand Caravan (from the brake drum removal thread), in the words of Jello Biafra, has got a bigger problem now. A foot or two aft of the ABS pump, the rear lines have short braided sections. At either end of this section, there was a little plastic clip to hold the lines parallel. They didn't even mount the lines to the body, all they did was rust out two half-inch long sections of each line.

I was thinking I would have to replace the whole line, but it occurs to me I could probably snip the braided sections out, including the rusty bits, and just union in a 10" long patch of new line in place of the braided sections.

I've worked with flare fittings on copper high-pressure piping before. How different is it in the automotive world? Is there a good flare tool kit available? Where to get the fittings?

Or am I being stupid and I should have it towed somewhere and done professionally? Thanks.
Sept. 26, 2011 12:55 p.m. emodspitfire Reader

Pics?

The flex sections probably need to be there because the Body/Frame flexes in that area to provide ride compliance.

Beyond that replacing brake lines is pretty straightforward. Takes time and patience from my experience.

Rog
Sept. 26, 2011 12:58 p.m. Duke SuperDork

emodspitfire wrote:

Pics?

The flex sections probably need to be there because the Body/Frame flexes in that area to provide ride compliance.

Don't have any, but maybe I could get some. It's right below the driver's seat in a huge flat area of unibody pan, so it sure as heck shouldn't be flexing there. I imagine it is in place to absorb ABS pulses, but I could do the same thing with an expansion loop. Besides, it is a utility vehicle that gets about 2-3k a year on it.

In the meantime, anybody that has a 3rd generation Caravan - jack it up and inspect the rear brake lines in this area. This went suddenly and caused a complete loss of hydraulic pressure. Not fun. I only avoided an issue because I was driving in town at very low speed.
Sept. 26, 2011 1:07 p.m. Zomby woof SuperDork

If you can remove the next closest fittings on either end, pre-made lines are usually available in all different sizes, and usually cheap.
Sept. 26, 2011 1:15 p.m. Duke SuperDork

Zomby woof wrote:

If you can remove the next closest fittings on either end, pre-made lines are usually available in all different sizes, and usually cheap.

The problem is, since these are the rears, the next closest fitting to the back is about 6 feet away, and the lines are routed (with lots of jinks) over the gas tank. I could conceivably remove them at the ABS pump and forgo 1 union, but that doesn't look easy due to access issues with the top of the ABS pump.
Sept. 26, 2011 1:28 p.m. Zomby woof SuperDork

You need a double flare tool. Easy job. We had to replace the lines on my sons car front to back a year ago. I hadn't done it in 20 years, but it was easier than I remembered.
Sept. 26, 2011 1:32 p.m. dculberson HalfDork

I've done exactly this before, cut lines, flared them, and used unions to "patch" the lines. Whatever you do, do NOT use compression fittings! I know you didn't mention doing so, but some people seem to think it's okay. But they're only rated for double-digit PSI, not the huge pressures that brakes will see.

For flaring, I used the cheap-O flare tool kits from the local auto parts store. They're truly terrible. You can get a decent flare out of them with a ton of work, but you can also just break the dies and have to cut the line again. Eastwood makes a better flaring tool, but it's a good bit more expensive and requires the use of a vice so it's not possible to use while leaving the lines on the car. A hydraulic tool like the Mastercool set would work best, but they're around $300!

If I had it all to do over again, I would probably just do the cheap flaring tool and take my lumps. Practice on some scrap tubing first. You can get the fittings, including unions, at the auto parts store.
Sept. 26, 2011 1:57 p.m. Appleseed SuperDork

My car has several. So far so good. Yes, I know pressure will find the next weekest point, but, really, how much is it worth on a $500 beater?
Sept. 26, 2011 2:00 p.m. dculberson HalfDork

Several whats, compression fittings or properly flared unions?
Sept. 26, 2011 3:10 p.m. turboswede SuperDork

Seriously, compression fittings are a big no-no.

Man up and get a flaring tool and properly do the job.

Replacing lines isn't too bad, especially when you have a model to work from. The tools are much cheaper to buy as well :)
Sept. 26, 2011 3:19 p.m. Taiden Dork

FWIW

http://www.youtube.com/watch?v=atnL5GxC0aA
Sept. 26, 2011 3:32 p.m. dculberson HalfDork

Could he not find a shirt and pants? Spent all his money on the flaring kit? Bwahahaha!
Sept. 26, 2011 3:35 p.m. fasted58 Dork

NEVER use compression fittings !!

Auto Zone has a double flaring tool in the loan-a-tool section, or you can buy it new for around $25. It will flare single or double so use the correct flare for your type fittings. Works pretty decent but practice on a few pieces first. You should be able to find a tubing bender for cheap at AZ or AA also. Again, practice on some pieces to get the hang of it.

If you plan on doing only a few flares $25 ain't bad. If in more frequent use a better quality tool would be worth it IMO.
Sept. 26, 2011 7:10 p.m. 93gsxturbo HalfDork

The bar/cone/clamp flarers are truly terrible. You will spend forever cutting and dressing the line properly, only to have the line end up with a kittywhompus flare that won't seal. Practice doesn't really make perfect with these devices. They are also a huge pain in the butt to use on-chassis, which it sounds like you want to do in this situation.

I would suggest beg/borrow/steal a Mastercool flaring kit. Ask around, someone might have one. They work so well its not even fair. They can be used 1 handed under the car, will make a perfect flare every time, and remove so much frustration, I actually look forward to busted lines now.

$300 seems expensive, but its a lifetime tool with 1000 uses, can flare Saginaw (power steering) lines, fuel line quick connects, AN fittings, stainless steel, you name it, the Mastercool can flare it. You can pry mine from my cold dead hands.
Sept. 26, 2011 7:34 p.m. Duke SuperDork

Thanks, I'll look into a Mastercool. Yes, I'd like to flare it on the car. No, I'm not going to try compression fittings.

If I can't source one locally, would you be open to renting me yours for a weekend?
Sept. 26, 2011 7:36 p.m. Taiden Dork

dculberson wrote:

Could he not find a shirt and pants? Spent all his money on the flaring kit? Bwahahaha!

It was hot out and I was lazy!
Sept. 26, 2011 10:16 p.m. jimbbski Reader

93gsxturbo wrote: I would suggest beg/borrow/steal a Mastercool flaring kit. Ask around, someone might have one. They work so well its not even fair. They can be used 1 handed under the car, will make a perfect flare every time, and remove so much frustration, I actually look forward to busted lines now.

$300 seems expensive, but its a lifetime tool with 1000 uses, can flare Saginaw (power steering) lines, fuel line quick connects, AN fittings, stainless steel, you name it, the Mastercool can flare it. You can pry mine from my cold dead hands.

What he said X2! I have one and I'm sure that this is a tool that will out last me. The looking forward to busted lines part, ah no.
Sept. 26, 2011 11:34 p.m. donalson SuperDork

got to play with this not long back... friend called with "no brakes" in her suburban... ended up a spot between the flex line to the axle and the frame rail...

ended up using the cheap cutter/double flare tool, one end was at the junction block to the soft line other end I had to get a long enough straight section to bend out from the frame (between the body and frame) so I could cut it and flare it...

worked well... but had to use a C clamp on the bar clamp portion because it didn't hold the tube very well.

was a lot easier then having to re-run the entire line to the back and front passenger on my AWD astro van
Sept. 27, 2011 12:52 a.m. Appleseed SuperDork

dculberson wrote:

Several whats, compression fittings or properly flared unions?

Proper double flares. My mechanic buddy wants me to come back. Dead customers are not repeat customers.
Sept. 27, 2011 1:23 a.m. fasted58 Dork

You could possibly replace that long a line by mixing different lengths of tubing and connecting w/ brake flare unions. If the line ends up too long some creative bends and routing will i.e. shorten the length to fit. It might not be factory looking but it works. I had to do that before when a flare tool was not available in the time I had.

But to earn the brake line merit badge, you're really gonna want that flaring tool.
Sept. 27, 2011 7:02 a.m. porksboy SuperDork

Might it be easier to run a new line in a different location? Like maybe a longer line but gor AROUND the tank and all the other crap. It would be easier than over the tan.
Sept. 27, 2011 7:14 a.m. Dr. Hess SuperDork

Yeah, a pre-made brake line or several put together and bent to fit may be easier to get installed. They are pretty cheap at any parts store. They come with a proper factory double flare and fitting on each end. Just another option.
Sept. 27, 2011 8:30 a.m. AngryCorvair SuperDork

keep in mind that the tube bundle is one of the first things to be installed under the car on the assembly line, so they will be the most difficult to R&R.

so, if you have to reroute the line to make the job doable, and if you run the line where it will be subject to road debris, you could make a trip to the junkyard and get a whole bunch of the crinkly black wire harness loom stuff, and ty-rap it to the line. if that's not enough protection for you, you could buy some vinyl tubing from Lowe Depot and put it over the new line.

FWIW, those braided sections are there to (1) reduce the vibration in those long tubing sections and (2) to reduce the precision required in the forming of those long tubing sections.
Sept. 27, 2011 9:04 a.m. kb58 HalfDork

Having plumbed cars with both hardline and flex hose, I'll never use hardline again, UNLESS you have a very high quality ($$$) flairing tool. Otherwise, the endless leaks will drive you crazy.

Also, if you have only one or two cars to plumb, the cost of the proper flairing tool ends up making the hardline solution more expensive than just doing a flex-hose system.
Sept. 27, 2011 12:35 p.m. noddaz New Reader

Ahh, brake line are FUN... Naw, not really. But they are time consuming to do right. I had a GMC Safari that had rusted out the right front brake line and had it blow out near a local shop. I didn't want to do it so I spent $300 (ouch) to have the shop do it. A year later the brake line rusted out abut two feet from where the shop put the splice in. So the second time I fixed it myself and replaced the entire section of line. And while I was bleeding the brakes the line from front to back blew out... So I ended up fixing that too. Something to remember is sometimes the car has special sized flare nuts on the factory brake lines. And you will not find these anywhere as a replacement. So save the old lines in case you have to reuse the nuts. Something else to remember. Foreign cars use bubble flares and require a different tool for making those. I oiund that out years ago when making brake lines for my 1986 GTi... Also found out that British cars have a different thread than German cars... But that is a different story...

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