I am running out of brake line to flare. Specifically it is the original 5mm line that goes through the wheel well into the battery box. The other flares are tight and do not leak. After about 3 flarings I have gotten the last flare down to a very slow leak. Unfortunately I am running out of original line to flare. What is making it hard is that I have to do the flaring in the wheel well. Any tips or suggestions. Sorry about the slightly blurry picture. Guess it is Miller time.

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Sorry not to have an answer but instead a question. What type of Flare are you putting on?

The ones on my older 84 300D are what is called a bubble flare and that is not what US vehicles use. That means I had to buy a bubble flare kit because My US flare kit would not work.


Generic issues with flare kits are leaving the proper amount sticking out of the clam and having the tubing slip in the clamp when you are trying to flare it. Either one can result in a poor flare.

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84 300D, 82 Volvo 244Gl Diesel

The hose connection is a bubble (original style). The replacement hose came as bubble. The union is a double flare. The only available kit was a metric double flare. The replacement line had bubble flares at both ends. One end fit into the hose. The other end I cut and double flared. The pita is trying to double flare the installed original line in the wheel well.

If I read it correctly the double flared tube is not supposed to seal on the bubble flare hose.

I got my bubble flare kit on eBay. Don't know if local Autoparts sell it or not. Perhaps NAPA would have them but likely expensive.

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84 300D, 82 Volvo 244Gl Diesel

I don't know if this means they sell the bubble flraring kits or not.

Know How Notes - How to Make a Double Flare Brake Line

Tips for Making Successful Bubble Flares

metric flare tool, fittings?

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84 300D, 82 Volvo 244Gl Diesel

The replacement hose (bubble flare) has a replacement pre-made line (bubble flare) screwed into it with bubble flare nut. As I had a metric double flare tool kit I cut the bubble flare off the other end of the premade line and double flared it. That worked well. The union connecting the replacement line to the piece of original line coming out of the wheel well wall is double flared. Trying to double flare (or any type of flare) on the original piece of line is a pita working in the wheel well. I am getting better at it though. The first flare attempt produced a gusher. The second not as bad. The third only a very slow drip.

No need to fear. I think most U.S. cars switched to bubble-flare ~2000. I dbl-flared some from a JY car for my 60's U.S. cars. Of course, the tube nuts don't interchange. You can find 3/16" tubing sold w/ metric nuts on ebay. From a kit description:
M10 X 1.0 Threads
Connects 3/16" Bubble Flare Lines

Several youtube's show how to make a bubble-flare using a dbl-flare tool. I haven't tried, but recall the trick is to use the flat side of the holder. Those were from when bubble-flare tools cost >$200. Now they sell for $35.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Another option. Take the rubber line down to your Parker or Swagelok store and have them build a teflon lined SS braided hose a bit longer than the factory unit and skip that loop so you get back to a good connector. Use a flexible tape and figure out the best routing so there's no strain on the new line. Take the removed line with you and the shop can install whatever fittings you need to hook everything up properly and you're done, with the added benefit that the new line will last forever.

Dan

Thanks for the help. The problem/pita still is flaring the original steel line coming out of the wheel well. I see no way that line is coming out for flaring on the bench. As I said each time I flare it there is less leakage. Maybe this time I'll get it right.

As mentioned, your "metric" tubing should be the same as "3/16" SAE tubing", so you could dbl-flare it, if you consider a dbl-flare more reliable. Use a 3/16" female inv flare coupler (Autozone bubble packs) to connect your car's tubing to new tubing. For the new tubing, buy a factory-made section w/ bubble-flare on one end to fit your hose and dbl-flare the other end for the coupler.

But, I would fix it simpler. You can buy a "soft seat" (copper or aluminum) washer to slide over your bubble flare to insure a seal. We use them all the time in aerospace to seal bad AN flare fittings, so "should work". You could do similar by putting a thin O-ring over the bubble flare to seal. It isn't like your brake system doesn't have other rubber parts. Viton is best, but HBNR "AC" O-rings should also work (typ. green or blue).

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Nobody wants to hear me say this but here goes.......

Again, a trip to your Parker or Swagelok store. Get an INSTRUMENT GRADE compression fitting and be done with it. DO NOT head to the hardware store - hardware store compression fittings are worthless and WILL leak or even blow off at as little as 50 PSI. Instrument grade compressions are good for 2200 PSI and probably even more - way more than your brake system uses. This will make a permanent and safe repair.

I put my booty where my mouth is on this one. My '78 Cadillac Fleetwood lost a line and the way it was run it was almost impossible to change it out the "proper" way so I procured one of the fittings mentioned (I used them all the time for toxic gas plumbing at work) and did the deed. I later sold the car to my bros GF who used it for an airport limo - no issue up to the time she sold it for a newer model (several years). It never leaked a drop from that spot.

Stand back for all the replies from well-meaning folks who have no idea of the type of fittings I'm referring to - happens every time I post up about this. I'm NOT recommending this fix - just saying that it works.

Dan

Thanks. several good ideas. Easiest would be the instrument grade (high pressure?) compression union. Looked at Swagelok and Parker.Wouldn't you know it. Smallest fitting I found was 1/4" or 6mm! Mercedes line is 5mm. I understand 5mm and 3/16" are interchangeable. .009" difference. So I went back to the internet and watched several You Tube videos on bubble flares. 3 of them said a good bubble flare can be made with a double flare tool. Here is the trick. Turn the clamp upside down when inserting the line as in use the flat side of the clamp. Project the line to the first step on the die from the clamp as when double flaring. Insert the die into the tubing and tighten down the arbor as when double flaring. The result is a bubble flare.

Yep, as I said in post #7.

Yep, as I said in post #7.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

there are two kinds of bubble flare, one is a DIN or ISO type bubble flare like you see on MB, BMW, Chevys etc. The other is the ancient SAE bubble seen in morris and other british brands.

The ISO type requires a specific tool to accomplish and is not available usually at brick and mortar parts stores. Amazon has an OTC brand which is pretty good, or if you have a good vice you can buy the little cube and insert by Kent moore which are GM original service parts.

If you are running out of line, remove the line till a good servicable end like the ABS pump and install new line - the new green armor clad line is exactly the color of MB line and is also available in upto 7ft lengths with proper bubble flares and nuts. Or you can get some cunifer line from NAPA, a pack of nuts and bubble flare it yourself.

You can also sort of ham it with a larger line and make a spring like coil in between to shorten it to size. The bending tool at harbor freight is a good item for this.

a word of caution in bubble flares. It takes practice on atleast 5 or 6 flares to get the hang of it - bubble flaring requires lubrication on the flare to not damage the tooling and not damage the flare face. (use silglyde - dont worry its compatible with brake fluid, which you will be bleeding out anyway)

for bending - practice on some scrap line to get the hang of it - cunifer bends like warm wax compared to steel line and is extremely long life.

Do not fall for the "bubble is half double flare" - you end up with an SAE bubble, the SAE bubble flare of british cars used conical nuts like double flares, the SAE bubble also is narrower compared to the proper DIN/ISO bubble and using it with a DIN/ISO nut will make it let go under hard stop braking pressure.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

good luck with that upside down clamp, the bubble flare tool of that shape has screwed in pressing arbors so that the line is squarely pushed in, double flare arbors are not screwed in type and will rock sideways causing you great grief. BTDT Furthermore the two clamp faces should be perfectly even to make an even flare (even with the correct tool)

3/16 line is cheap and plenty at all parts stores - same as 4.8mm metric. The nuts are the important bits - dont use corroded hardware as new stuff is very cheap. They are in the sub 5 dollar price range for a blister pack of 5

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)