Rear Brake Line Flaring Topic is solved

[cn90]

Yes,

Exact same M10 1.0 mm bolt as xHeart said.
The same M10 x 1.0 mm bolt is used in BMWs and Volvos.

I wrote a brake caliper rebuild 8 yrs ago (in 2011).
See the link below, if you scroll down to step #14, you can rebuild using new seals in situ, this way you don't have to cut the metal line, redo the flare etc.

DIY: 98 V70 BRAKE HYDRAULIC OVERHAUL (HOSES, SEALS, PARKING)
viewtopic.php?t=37721


PS: Here is another thread by vjaneczko:

DIY: FLARING YOUR BRAKE LINES
viewtopic.php?t=32317

[polskamafia mjl]

This is a short write up on flaring the rear hard line on the passenger side; it is largely a rehash of cn90's thorough write up which can be found here https://www.bimmerfest.com/forums/showt ... ?t=1350813 .

Parts list:

O'Reilly's Auto Parts
Copper Nickel hard line (1):

Cu - Ni Line

M10 x 1.0 flare nut (3):

Flare Nuts

Union (1):

Union

Flare Nut and Union

Flare Nut and Union

Amazon
Neiko 20657A ISO Bubble Flare Tool (1)

Bubble Flare Kit

Flare Tool Instructions

I removed the old caliper and placed it in front of the hub so I had easy access to the hard line.

Next I cleaned all of the grime off of the hardline using brake cleaner and sand paper.

I began with the new section of Ni-Cu tubing and cut off the double flare that came on the line. After cutting the line I used a small file to ream out the inner diameter and remove any burrs. Next, I used a large file to chamfer the end of the brake line. Next, I made the first bubble flare on the Ni-Cu line. I used this as the caliper side.

Caliper end bubble flare

Bubble flare close up

Then I trimmed the Cu - Ni line to size using a tube cutter and once again cleaned up the end using a file as explained previously before making the second bubble flare. This end will connect to the old hardline thorugh the union.

Ni-Cu line on the new caliper

I installed the new caliper and screwed the union on to the flare nut.

Next I cut the old hard line along the straight section, slid the new flare nut on, and installed the brake flaring tool.

Old hrad line with flaring tool

I used brake cleaner to keep the flaring tool as clean as possible and then made the last bubble flare.

With the old line flared I screwed the flare nut into the other end of the union and tightend both flare nuts.

Completed brake line

Next bleed the brakes and check for any leaks at the union and at the new caliper.

Here's a shot of the old caliper with the butchered brake line nut. So much trouble over such a small thing.

Old caliper with rounded brake line nut

Overall it was a pretty easy process. Take your time and make sure you're making good flares. I would also recommend using a pair of vice grips with rubber hoses over the jaws to pinch off the flexible section of brake hose on the delta arm. This should help reduced how much brake fluid leaks out of the hard line after you cut it. I would also recommend buying a spare piece of brake line to practice on before hand. For a general overview of the brake flaring process I found this video super helpful: https://www.youtube.com/watch?v=Qli4jSG ... w&index=81

[cn90]

Great job.

I wonder what if you cut so close to the caliper, and if there is enough metal line that you can just make a flare right there (of course with a new nut). This way you don't need a union.
Just wondering...

[polskamafia mjl]

That's a really good idea. I think there would be enough line to do that. Good thinking! I think if I had to this all again I would do just as you suggested.

[abscate]

It’s really easy to monitor these for leaking over the next few months.

Put a sharpie mark in your brake fluid reservoir at the fluid level and see if the level drops; if it doesn’t you are good to go.

[cn90]

Another way to monitor leak is to use a flash light and look directly at the union every few days. If there is any leak, you will see it being wet.

[cn90]

Very nice job.
I remember replacing the piston seal and boot back in 2011.
In the photo below, you can see that:

1. I rebuilt the caliper in situ. If people do that, there is no need to replace the caliper or make new bubble flares etc.

2. If people decide to replace the caliper, then cut close to the nut. I believe there is enough metal line to make the bubble flare..

[FireFox31]

If you cut the hard brake line while it's on the car, how do you stop the brake fluid from dripping out while you try to make a new flare?

This is a great thread. Both of my rear caliper nuts are rounded. Since I knew nothing about flaring, I bought two new brake lines from Volvo for about $40 each. All I needed was two properly sized "bolts", a flaring kit, and this information.

[Clemens]

No idea how to stop the fluud from dripping.

But I managed to get the roubded off M10s off by filing them down to the next standard (US) size where I happened to have a snap on flare nut wrench that really got the job done.
It was basically a press fit, I used a small brass hammer to knock the wrench onto the modified flare nut.
Just an idea, but most everyone has a small file at home, so this could save you time and some bucks.

[xHeart]

No idea how to stop the fluud from dripping.

A depressed brake pedal closes the valve, hence no drip, other than gravity at work.

This may help too viewtopic.php?f=9&t=91484&hilit=2001+V70XC&start=10