Flush Brake Line or Replace

[Bingster]

I have a line from the MC to the rear brakes and I'm wondering if I should run some sort of solvent and compressed air though it or form a new one.

[Los_Control]

If it is original I would replace it, but would replace all the lines not just one.

 

If they look good and are not 75 years old you could flush the system ... Is recommended as normal maintenance on all vehicles to flush the brake fluid every 5 years or so.

Nobody does it but it is a good idea.

[soth122003]

How old is it? When I got my 48 years ago, I was working the brake system. When I finished and brake tested the pressure for an emergency stop, bam, the front brake line blew out under the radiator. Good thing I was in the driveway and not on the road. Had to replace the entire front brake line. Later I replaced the back line as well. Because the Dot 3 and 4 brake fluid is hydroscopic, you can and will get moisture in the brake lines. Since the old lines were steel they rust from the inside out. If you lines are old, replace them. Also solvent might make the line inside worse.

 

Joe Lee

[Bingster]

What is the new brake line material?  I seem to recall a bendable turning in the past.

[Bingster]

That's tubing.

[Jerry Roberts]

15 minutes ago, Bingster said:

What is the new brake line material?  I seem to recall a bendable turning in the past.

Nicop   nickel - copper . 

[Los_Control]

nicop .... it is a mix of nickle/copper.

Is certified for use with brake, fuel, ATF or can work for vacuum also.

It is softer so easier to work with, comes in 25' or 50' rolls is easy to order & ship online.

You flare the ends with the same tools as steel lines.

 

I use a 2"x4" wooden block in a vice and drill a hole the same size as the tubing through the 3.5" side.

Then when unrolling the tubing I run it through the hole and straightens it out so I start with a straight piece to begin with.

The smaller line is possble to bend by hand, a bender still does a cleaner job.

[Sam Buchanan]

If you don't want to flare tubing nicop lines with installed fittings are available in various lengths at your local auto parts store. I replumbed the brake and fuel systems on my P15 without having to make a single flare, just connected the appropriate lengths of tubing. Just make sure you get tubing with the proper fittings, lots of metric fittings out there.

Edited September 1, 2023 by Sam Buchanan

[Ivan_B]

3 hours ago, Bingster said:

I have a line from the MC to the rear brakes and I'm wondering if I should run some sort of solvent and compressed air though it or form a new one.

What makes you wonder? Is the line damaged, rusty, or just has dirty old fluid in it? How about all the other lines?

3 hours ago, Los_Control said:

Is recommended as normal maintenance on all vehicles to flush the brake fluid every 5 years or so.

That is actually every 2 years.

3 hours ago, soth122003 said:

When I finished and brake tested the pressure for an emergency stop, bam, the front brake line blew out under the radiator.

That's scary, the line must've been heavily corroded carbon steel ?

1 hour ago, Los_Control said:

nicop .... it is a mix of nickle/copper.

That's probably the best choice (not used by manufacturers because it is expensive).

26 minutes ago, Sam Buchanan said:

Just make sure you get tubing with the proper fittings, lots of metric fittings out there.

Flaring is really easy and, hey, who says metric is not right? ??

Edited September 1, 2023 by Ivan_B

[Sam Buchanan]

2 hours ago, Ivan_B said:

 

Flaring is really easy and, hey, who says metric is not right? ??

 

If you can get metric fittings to thread properly into old Mopar master and wheel cylinders you're golden........

[soth122003]

7 hours ago, Ivan_B said:

That's scary, the line must've been heavily corroded carbon steel

It was over 70 years old and looked good on the outside, but the inside must have been corroded as all get out. (which ironically the fluid did. LOL) What really sucked was I just finished replacing the fluid and bleeding the lines. Last check was the emergency stop test and the old line just blew out. The split in the line was about and inch long so no saving that whole section of line. 

 

Joe Lee

[Ivan_B]

Now you have me worried, since I am pretty sure my lines are all original. Rear ones are somewhat corroded and i was planning to do them, maybe next season. How hard did you brake? Was the car new to you, at that time, or have you driven it in the past? I did push my pedal hard all the way to the floor, in the garage, etc. Did not skid-brake on the road, though, because the tires are tiny and old. But I don't see how it will make much difference, versus stationary testing, in terms of the pressure inside the line. ?

[soth122003]

Think the kid darting out between 2 parked cars right in front of you add the adrenaline and Pow you don't know your own strength. The car was new to me, hence the brake checks and the bleeds. No matter how hard you hit the brake, it should not go to the floor unless something is wrong.

 

Joe Lee

[Ivan_B]

That is certainly true. I am just thinking that the line pressure during stationary testing and road testing should be similar (under normal conditions). So if I press the pedal hard in the garage, that should be sufficient. ?

[Sam Buchanan]

1 hour ago, Ivan_B said:

That is certainly true. I am just thinking that the line pressure during stationary testing and road testing should be similar (under normal conditions). So if I press the pedal hard in the garage, that should be sufficient. ?

 

If you have any doubts about brake system integrity........don't drive the car, fix the brakes.

[Los_Control]

I replaced all the lines & wheel cylinders on my Dodge, the master cylinder looked good enough to rebuild.

When I bled them out & was pretty happy with how it felt ...... I did the panic stop routine stomping on the pedal as hard as I could. Truck was still on jack stands in the air.

The pedal went straight to the floor.

 

Then I swapped out to a 2stage master cylinder. .... I figure the original probably was honed out to far, needs a sleeve.

I just threw it in a box on a shelf and never gave it a second thought.

 

I personally think the panic stop test is very important .... zero reasons why that pedal wont hold up to stomp on it as hard as you can.

[Ivan_B]

1 hour ago, Sam Buchanan said:

If you have any doubts about brake system integrity........don't drive the car, fix the brakes.

Good point. I did not have any doubts (and never-ever specifically did the "panic stop" tests with any of my cars) before Joe mentioned that his apparently "good" looking line just let go. Now I have doubts ?

Having a hose blow-up is something expected, this is why I always get new ones if I see any cracks or other signs of aging in the outer layer. But a steel line exploding, this is something completely new to me.

Edited September 2, 2023 by Ivan_B

[Sam Buchanan]

14 minutes ago, Ivan_B said:

Good point. I did not have any doubts (and never-ever specifically did the "panic stop" tests with any of my cars) before Joe mentioned that his apparently "good" looking line just let go. Now I have doubts ?

Having a hose blow-up is something expected, this is why I always get new ones if I see any cracks or other signs of aging in the outer layer. But a steel line exploding, this is something completely new to me.

 

Way back in the previous century when I was just a youngster my first car was a 1963 Beetle. A stop sign on a rural road was partially obscured by foliage (that is my excuse...) which resulted in me reducing the very high velocity of the poor bug to stationary status in as short a space as possible. Just before all the speed was bled off the brake pedal went to the floor and I rolled out into the intersection. Fortunately the mom in the big Buick had seen me in time and was able to stop sufficiently that only the driver door on the Bug was caved in. A very close call.

 

A steel brake line had ruptured which meant the single chamber master cylinder lost all pressure. Many decades later I still remember that near catastrophe......my P15 has a WilWood dual chamber master cylinder....and ALL new brake lines and hoses.  

[Los_Control]

Something similar a few years ago in my 1991 chebby.  6:30 AM and at a stop sign. 

Residential neighborhood, so many cars parked on the street in front of the houses, I had to inch out into the intersection to see if it was clear.

 

All looked clear so I let out the clutch and was going. ..... Then a lady driving 40mph using the rear view mirror to put on her makeup comes from nowhere.

I stomped on the brakes so hard the right rear wheel cylinder blew out. ..... Thinking back on it, I only had the truck for a year or so & never panic checked the brakes before.... they worked fine I thought. Until they were needed.

[Doug&Deb]

If you have any doubts at all about any brake components replace or rebuild them. You can’t put a price on safety.