Testing brake line corrosion
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Testing brake line corrosion
I have owned my '69 for over 3 years now and unfortunately none of the car's history of receipts included any information on the brakes.
Up until recently the brakes have stopped perfectly with a rock solid pedal. Cosmetically the calipers and lines look like they have a little surface rust but otherwise are fine so they might have been reproductions at one time.
My master cylinder is the type with bleeders installed in the housing, which I assume is to "bench" bleed on the car.
My real question is I just tested my brake fluid with the Phoenix Systems brakestrips and according to their scale I have anywhere from 0-100 ppm of copper in the fluid.
I have replacing the rubber hoses on the schedule, but now I guess I'll be doing a fluid flush as well.
Is there a good way to decide when to replace the steel hard lines other than for "piece of mind"?
Up until recently the brakes have stopped perfectly with a rock solid pedal. Cosmetically the calipers and lines look like they have a little surface rust but otherwise are fine so they might have been reproductions at one time.
My master cylinder is the type with bleeders installed in the housing, which I assume is to "bench" bleed on the car.
My real question is I just tested my brake fluid with the Phoenix Systems brakestrips and according to their scale I have anywhere from 0-100 ppm of copper in the fluid.
I have replacing the rubber hoses on the schedule, but now I guess I'll be doing a fluid flush as well.
Is there a good way to decide when to replace the steel hard lines other than for "piece of mind"?
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I replaced mine because one line had a leak and I could see hole/crack, one test is to take it to a parking lot and stand on the brakes, you only have to go 5 mph and hit them hard, if the pedal goes to the floor you now have found the week spot and your lines need replacing. This is not some stupid made up test this is how the DOT took one of my old cars off the road when I was 17 
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
I appreciate the reply.
The reason I am looking into my brakes is due to the car pulling left when I brake hard. I don't see any badly worn suspension components being the cause so my focus is the right front caliper. If it has a problem, might as well sort out the rest of the braking system "while I'm at it."
I haven't detected any leaks but it's interesting in my brake strip test the rear reservoir of the MC was the one indicating more corrosion. Not surprising as that feeds the longest of the steel lines in the system.
The reason I am looking into my brakes is due to the car pulling left when I brake hard. I don't see any badly worn suspension components being the cause so my focus is the right front caliper. If it has a problem, might as well sort out the rest of the braking system "while I'm at it."
I haven't detected any leaks but it's interesting in my brake strip test the rear reservoir of the MC was the one indicating more corrosion. Not surprising as that feeds the longest of the steel lines in the system.
