Brake Lines

[rlsllc]

Looks like fun, good job Scott.

I've ran what seems like miles of brake line here in nice, rusty Ohio. I couldn't tell you how many cars, trucks, jeeps and vans that I've replumbed from end to end. Brakes, gas lines, rear heater lines, it's all fun.

I always bend by hand, with exception to a sharp 90 near the end of a piece, sometimes I do those as well. If you can, hold the old piece that you removed along with the new, and just bend the new to match. I sometimes just rip out all the old and wing it, just be sure to use your head on what to avoid, keep it tight to the frame, body, etc, and clamp it down. I use double flare unions and short pieces sometimes when it's tight, although I don't like to. I steer clear of compression fittings, other than an emergency.

A shot of brake cleaner followed by paint will stop the rust where you flared the lines, and Larry's right...cut slow, strait, clean and ream. Use a sharp cutter. I've found that a drop of oil on the die helps, too.

I roll the line around a piece of pipe to make the "spring" that allows body movement, it's a fun trick. It takes a lot more line than you think to make one of those springs.

The hardest part is finding some of the goofy late model connectors, I try to clean up and reuse the originals when I can.

[Jboy2]

Lookin good. I know how it feels to make brake lines. This weekend i finished replacing all the lines from the ABS module all the way to the caliper/Wheel cylinders. But atleast you know that it was done correct and that it will work for long

[fingernipp]

Turns out Napa sells a products called Polyarmour. From what i read its double walled and can be hand bent. Price seems resonable too for a 25' roll. Anyone know what size fittings ill be needing or any other details? I plan to replace every hard line. I dont trust those rusty lines while towing my 2500lb boat on a 1000lb trailer.

[97CargoCrawler]

I did something really fun today! Ever tried double flaring a brake line still attached to the van with brake fluid running out continously? That was so much fun. I would equate it sewing an accident victims aorta back onto their heart in the middle of the street. Best part was when I was done, and it leaked.

I think the trick to double flaring is buying a quality tool to do it. My $25 Powerbuilt double flare tool I bought today just for this purpose was a hunk of $hit. The way they cut the notches on the tool made it so that the brake line was not quite perpendicular to the clamp. So my flares were slighly tilted and of course now they leak. Fantastic. I could have bought new brake lines for cheaper than the tool.

[fingernipp]

Yeah i got the cheapo tool sold at autozone. I also had the crooked flare issue but found that eyeballing it all as straight as possible gave good results. I had a fitting leak and had to cut it off and make a new one while under the van. Sucks quite a bit, but i got soo good with the tool that it only took a few mins.

[peter]

I did something really fun today! Ever tried double flaring a brake line still attached to the van with brake fluid running out continously? That was so much fun. I would equate it sewing an accident victims aorta back onto their heart in the middle of the street. Best part was when I was done, and it leaked.

[Rebel]

97CargoCrawler wrote:
I did something really fun today! Ever tried double flaring a brake line still attached to the van with brake fluid running out continously? That was so much fun. I would equate it sewing an accident victims aorta back onto their heart in the middle of the street. Best part was when I was done, and it leaked.

Man, I hate that. Reminds me of the plumbing work I'm doing in our house. You think you're finished only to find you started a leak somewhere else so back to the hardware store,,again and again and again. When does it end ?????

[97CargoCrawler]

OK guys and gals I need some serious help!

My 6" lift has been complete since last Thursday but I have not been able to test drive the van and appreciate a weeks worth of hard labor becuase of my leaking brake lines.

Here's the problem: The braided hose lines for the calipers I got from Dan at OLV had a metric bubble flare fitting on them. The hard line screwed right into it no problem but it was pouring fluid out after I was done tightening it. I didn't know anything about any type of flare until this happened and I started researching. From what I've read here, and comparing what the flare on the hard line looks like to photos, it seems the hard line has a DOUBLE INVERTED flare. Obviously a double inverted flare is not going to mate with a bubble flare because the flares face opposite directions like this: ---< >--- and you need ---<<--- to make a seal.

Now, are the stock lines metric or standard? The new braided hose I have has a 10mm 1.0 female coupling, and the hard line on the van seemed to screw in perfectly. However, the guy at the local brake shop tried to convince me the hard lines are 3/16" standard. But when I screw a 3/16" standard fitting into the braided hose it's very loose.

I need clarification because I need to run new lines this weekend so I can finally drive my monster-van!!!! Are the stock hard lines metric or standard on a 1997 GMC Safari 2WD? (I think they're metric with 10mm 1.0 flare nuts) AND are all the flares double inverted type, and I mean all of them from the ABS pump to calipers and wheel cylinders???

Also, does anyone know the length of the front brake hose for the AWD van? My new calipers are for 1500 series trucks, which just happen to be the same as the AWD Astro/Safari calipers. With my spindle lift I need hoses at least 4" longer than what I had on there. I'm hoping to just scrap the new braided ones and go AWD OEM just to avoid any adapters to convert double flare to bubble flare.

Also need to know approx. how many feet of tubing i will need to run new lines from the ABS pump, to the front only.

Need to buy the parts tomorrow, so really could use some helpful info ASAP! Thanks!

[Rileysowner]

You can get adaptors to go from a double flare to a metric bubble flare. I think Napa would have them.

[97CargoCrawler]

Yes, I bought some from CarQuest. I'm using them, and I think they're the reason for the current leak. The bubble flare end seals, but the d-flare end has a leak. I made damn good looking flares so I don't think that's the problem. And I used 2 new adapters after the first two leaked. Even bought a $20 tubing nut wrench to crank 'em down tight. They seem problematic so I want to skip them altogether.

[97CargoCrawler]

Just a tip for you guys who have already done or are planning to do their brake lines:

If you're not re-using the stock flare nut on your new lines make sure you purchase new nuts that are the correct thread type!

I don't know which van years have what sizes, but my van is metric everything, INCLUDING the brake lines.

The guy at the local parts store tried to convince me that I have standard fittings (flare nuts) just because it is an american car. I had my doubts and sure enough the lines on my van are metric.

Now this is where buying new brake lines can get real confusing. A 3/16" standard line is the same as a 4.75mm metric line as far as tube diameter. The thing you really need to pay attention to is the flare nut thread type. You want a metric thread nut with a standard flare tube end. The standard flare is the 45deg. inverted double flare (inverted cone).

Now for the REALLY SCARY part: If you happen to use the wrong flare nut, like a 3/8" 24 that comes on a standard 3/16" line for american cars it will screw into your brake hoses and wheel cylinders, BUT it will feel very loose as you screw it in. You may even be able to torque that nut down and think everything is OK. But those threads will be barely hanging on and one good stomp of the pedal or something and you may be looking at a real disaster!

Here's a photo of the correct size line, at least for my 1997 Safari (disregard the 20" length). The line diameter is 4.75mm (3/16" equivalent) and the flare nut is a 10mm 1.0 thread nut. And of course the tag doesn't tell you what size the nut is!



And notice, it says it's for a JAPANESE car!



I know all this may sound confusing, especially to those who know nothing about thread sizes or brake lines. But if you get anything out of this post is should be to make damn sure you have the correct flare nut size before you redo any brake line on your van! Take the old nut into the parts store and compare. DO NOT take your old brake hose or wheel cylinder into the parts store to check size because the wrong flare nut will screw into those! I speak from experience! I had two separate shops try to convince me my brake lines were standard by showing me how a 3/16" line with a standard 3/8" 24 nut screwed right into the brake hose I had brought in. Albeit it was loose as it screwed in but at the time I didn't know that was unusual, especially when it was a brake specialty shop owner showing me. BE CAREFUL!

[BigFish246]

roll the line around a piece of pipe to make the "spring" that allows body movement, it's a fun trick. It takes a lot more line than you think to make one of those springs.

Roy,
Hi, What do you mean by 'make the "spring"?'

Thanks,
2000 Astro 140k miles.

[6spd_monte]

Holy Thread Revival, Batman!

What Roy means is, if you look at the brake lines as they come out of the master cylinder you may find that the brake lines are formed in a coil - like a spring. The purpose for this is to have some slack in the pipes so that in an accident the brake lines can stretch a bit and still maintain pressure. Without this the lines may tear if the accident were severe enough and then if the vehicle was still moving you would not be able to stop it.

[6spd_monte]

Like this:



That website gives a different reason. They say the coils are to provide flexibility in the lines so that the normal movement of body flex will not fatigue and crack the lines, and also to ease in assembly of parts.
I don't know which is right but they all make sense to me.

[BigFish246]

That website gives a different reason. They say the coils are to provide flexibility in the lines so that the normal movement of body flex will not fatigue and crack the lines, and also to ease in assembly of parts.
I don't know which is right but they all make sense to me.

Thanks, and sorry about thread revival... I didn't know if it's appropriate to start a new thread. My 2000 Astro does not have this coils. I faintly remember that my 1993 Astro did have some coil in the brake lines, & I thought it was odd. So now I know. Thank you.