Corroded and broken brake line - Planning on how to address?

[Trav]

Nice job! How was the Capri tool to work with?

 

[JHZR2]

Nice job! How was the Capri tool to work with?

Compact and easy.

Open the three 10mm bolts enough to slide tube in. Install depth setting tool to get the tube location perfect and consistent. Clamp down on tube by tightening the 10mm bolts. Install die with a bit of supplied red grease. Tighten down to stop. Release. Open 10mm nuts, done.

 

[JHZR2]

Not sure what has changed, other than due to sitting the rotors rusted up.

Drove the car about 150 miles. Brakes feel and operate great. But when coming to a stop, say, 5mph and below, I hear grinding. Not at higher speeds, no pull, pads have plenty of meat left.

I power bled the front calipers, left the rears alone as I haven’t touched them or the hoses yet. I think the sound is coming from the rear.

Perhaps I brake too gently. I believe in conserving momentum, not wasting it. Maybe I need to accelerate into more red lights?

 

[Trav]

Try applying the park brake lightly when moving, a few seconds usually does the trick if it is a little rust on the inside of the rotor drum.

 

[JHZR2]

Try applying the park brake lightly when moving, a few seconds usually does the trick if it is a little rust on the inside of the rotor drum.

Good idea. I don’t think it’s the parking brake though. It happens when driving very slow, like 5mph or less, coming to a stop, and then goes away when I let off the brake.

Still a good thing to do regardless, imo… so I’ll do it tomorrow am…

 

[JHZR2]

Try applying the park brake lightly when moving, a few seconds usually does the trick if it is a little rust on the inside of the rotor drum.

Not a parking brake. Definitely an iffy brake pad.

It’s on the rear, so no idea why it happened. It’s not like I touched the rear lines at all yet.

But what do you call this??

The amount of material isn’t great, but the other side is slightly less and looks much better.

I knew when buying that the fronts were new, rears had to be done before long, and that the last brake receipt recommended new lines. So the need to do pads and lines was not a surprise. It’s just so odd that it was working perfect, then it sat while I did the front lines, never touching the rears, and then I get this funky behavior from the rears.

 

[Trav]

I would call it broken/corroded. Replace the rotors and pads, check to insure the piston moves without too much effort, cleanup the bracket and replace/lube any pins. Replace with Zimmerman rotors and ATE pads?

 

[JHZR2]

I would call it broken/corroded. Replace the rotors and pads, check to piston moves without to much effort, cleanup the bracket and replace/lube any pins. Replace with Zimmerman rotors and ATE pads?

That’s my thought

 

[nwjones18]

I should have posted closure of the issue here, but I posted in the thread about flares and nuts instead.

Thread 'Help with brake line flare nuts'

May 17, 2025

I have a thread on repair of my 2008 MB ML320, but this is more general, so I’m making my own thread.

Here is a failed bubble thread line and nut:

Note the flatness of the bottom of the flare, and the squarish shoulders of the nut.

Now, compare to two nuts I’ve received that are supposedly for bubble flares:

Note how they have a tapered inner diameter?

The right one is OE, the far left is AGS and explicitly says bubble on the box. The middle is SURR, and is supposed to be for bubble.

I don’t think I’m crazy either. It seems that the...

• JHZR2
• Replies: 37
• Forum: Mechanical/Maintenance Forum

• 

In the end, used nicopp cunifer UK line, a capri DIN flare tool, and stainless armor.

View attachment 280836View attachment 280837View attachment 280838

Nice work! I’d never done brake lines before either and replaced all the hard lines on a Chevy tracker with that tool and nickel copper line. It’s not hard if you have all the right fittings

 

[JHZR2]

Nice work! I’d never done brake lines before either and replaced all the hard lines on a Chevy tracker with that tool and nickel copper line. It’s not hard if you have all the right fittings

Thanks! It would have been less of a wild goose chase if the parts stores had the right fittings. A Japanese or domestic vehicle I think would be OK.

 

[JHZR2]

I would call it broken/corroded. Replace the rotors and pads, check to insure the piston moves without too much effort, cleanup the bracket and replace/lube any pins. Replace with Zimmerman rotors and ATE pads?

Can’t say I’ve ever seen HG friction rating pads before.

It was bad!!

Time will tell if something else is wrong. The piston went back in easily with a clamp.

It went from quiet to grinding in a day, actually, in two weeks of sitting. Kind of strange. And it’s the side without the brake wear sensor. The other side is very low too - I bought the vehicle knowing that rear brakes were due soon, but no warnings, no lights. So this side is wearing faster than the other…

 

[JHZR2]

Bedded them in, no noise, good and hot. Maybe not hard enough though yet?

Notice the buildup on the pad top from scraping off the coating.

 

[The Critic]

Bedded them in, no noise, good and hot. Maybe not hard enough though yet?

View attachment 282721View attachment 282722
Notice the buildup on the pad top from scraping off the coating.

Normal, it takes a while for the pad to reach even pressure across the entire surface. Recheck in a thousand miles or so.

 

[JHZR2]

Normal, it takes a while for the pad to reach even pressure across the entire surface. Recheck in a thousand miles or so.

Thanks. I think the cars I’ve used these on in the past have all had pistons on either side of the rotor.