Brake line question

lcc014 · Post by **lcc014** » 29 Jul 2024, 06:09

I tried to replace the rear right caliper of my 1995 850 wagon yesterday but no luck to unscrew the brake line nut with flare nut wrench (11mm). I finally rounded the brake line nut.
I am thinking to cut the brake line between the caliper and the junction connection on the right side of the delta link arm. Then install an union to the new brake line to new caliper, Would this work ?
For brake line size, is it the 3/16" OD ? What about the brake line end, double flare or bubble flare ? What kind of the brake line is best to use ? This will be my first time to work on brake line, is there any suggestion/tip/recommendation to make the line flare ?

Thanks,

Ching-Ho Cheng

Oro · Post by **Oro** » 29 Jul 2024, 23:00

I would not introduce an extra union in a critical system like that. It’s not necessary. Get a new (or used) caliper before doing that.

Grind the parallel sides of the rounded nut flat. Using a crescent wrench or vice grips, then heat it and then simply screw it out. Remove the piston and clean the caliper out thoroughly as it very likely needs it after these years. Using a propane torch to heat a stubborn bolt is the easiest way to remove it, without damage.

You can google different ways to remove a rounded nut; this is one. And get a propane torch, using heat is always preferable to damage.

lcc014 · Post by **lcc014** » 30 Jul 2024, 05:31

Oro wrote: ↑29 Jul 2024, 23:00 I would not introduce an extra union in a critical system like that. It’s not necessary. Get a new (or used) caliper before doing that.

Grind the parallel sides of the rounded nut flat. Using a crescent wrench or vice grips, then heat it and then simply screw it out. Remove the piston and clean the caliper out thoroughly as it very likely needs it after these years. Using a propane torch to heat a stubborn bolt is the easiest way to remove it, without damage.

You can google different ways to remove a rounded nut; this is one. And get a propane torch, using heat is always preferable to damage.

Thank you for the suggestion. I did try vice grip without heating the fitting and it did not work since the fitting was Brass, too soft. Maybe, I really need to heat up the fitting.

Post by **abscate** » 30 Jul 2024, 06:37

Make sure the caliper is firmly attached to the carrier before tackling the brake line nuts. Its much easier to transmit torque on a firmly attached object.

Heat is your friend here. 30-59 seconds of propane blast on the union, cool for 5 minutes, repeat, cool, repeat cool. Then try torque with a flare wrench that grabs 4 sides. If it is rounded, a good sharp Vice-Grip will grab it.

AVOIT17 · Post by **AVOIT17** » 30 Jul 2024, 07:13

I have been fooled in the past by rust build-up on a 10mm brake bleed nipple. A 11mm wrench fitted perfectly (due to rust build-up) and tatam rounded the hex corners of the bleeder.

lcc014 · Post by **lcc014** » 30 Jul 2024, 08:12

abscate wrote: ↑30 Jul 2024, 06:37 Make sure the caliper is firmly attached to the carrier before tackling the brake line nuts. Its much easier to transmit torque on a firmly attached object.

Heat is your friend here. 30-59 seconds of propane blast on the union, cool for 5 minutes, repeat, cool, repeat cool. Then try torque with a flare wrench that grabs 4 sides. If it is rounded, a good sharp Vice-Grip will grab it.

The brake line nut/fitting was the very first item to undo. It was sprayed with PB Blaster for 4 days before tackling it, twice a day. So caliper was still mounted to the bracket with the 2 13mm bolts. I did use 11mm flare wrench to try to undo it but just rounded it. Then I tried the vice grip and still no luck and created more bite/scratch marks on the nut/fitting.

I will try the torch method

Post by **erikv11** » 30 Jul 2024, 08:40

Regular WD-40 is not penetrating fluid and will not help at all. But if you used WD-40 penetrant then great.

lcc014 · Post by **lcc014** » 30 Jul 2024, 08:59

erikv11 wrote: ↑30 Jul 2024, 08:40 Regular WD-40 is not penetrating fluid and will not help at all. But if you used WD-40 penetrant then great.

Sorry, my typo. I meant PB Blaster.

Post by **Clemens** » 30 Jul 2024, 16:30

file the fitting down to the next SAE size. If that doesn't work, file down to 10mm. Ask me how I know ...

And a high quality like Snapon flare nut wrench pays off. My craftsman 11mm slipped (yes, they are 11mm), but the next smaller snapon plus a few heat cycles did the trick

Post by **abscate** » 30 Jul 2024, 17:07

This is one of the places where snap on , pays off

Pay once,cry once