Cleaning metal brake line inner walls

[Chuck R.]

What would be the best method to purge the interior walls of the brake lines of potential light rust accumulations?

These lines have been hanging on the wall for about two years and even though I taped the ends, I still have visible rust at the flares.

I can easily handle cleaning the flared ends, but I keep hurting my eye trying to peek around those pesky bends to see if theres more in there

Anyone have a magic mixture that can best do the job?

I do NOT want to attach these lines and send contaminated fluid to my new calipers.

Thanks,

Chuck

[Chuck S.]

Re: Cleaning metal brake line inner walls

Chuckster, you come up with some wierd questions. Any cleaning agent you can flow through the tube that will eat the rust will also prep the wall surface for aggressive corrosion and may cause problems with your brake components. I would look at a mild mechanical cleaning...but how?

Have you ever used a weighted string to clean a gun barrel? Here's an idea: use an air blow nozzle to blow a length of stout binding sting through the brake line. (Gravity ain't going to help you much here unless you work off your roof). Once the string is through, tie a "properly sized" cleaning patch (try 1/4" X 3" long tied in the center to start) to the end of the string, and carefully pull it through the line after saturating the patch with cleaning solvent of choice.

Mineral spirits is probably the best solvent for cleaning the loose rust; however, you will also have to make a pass to clean the mineral spirits off the inside wall using something that won't harm your caliper seals and hoses. Brake fluid is a good choice if you don't have denatured alcohol or commercial brake cleaner.

Getting the patch sized right is of critical importance...get it too small and you won't get good friction on the walls; get it too large, and you could break the cord and loose the patch inside...then this little surface rust is going to be a secondary priority (You could try using the air blow nozzle to BLOW out the patch!).

Until you determine the optimum patch size, you should consider tying the patch about 2 feet from the string end leaving a little tail...that way, if you get the patch too large and it has too much resistance early (plan for the tightest bend), you can still pull the patch out before it travels too far.

When the dirty patch comes through, change the patch, and repeat the process until the patch comes out relatively clean; or, until your patience/enthusiasm evaporates, whichever comes first. You may find that it's not as rusty inside the tube as you feared, but I predict the patches are still going to be dirtier than you thought.

[Chuck S.]

Re: Cleaning metal brake line inner walls

Chuckster, you come up with some wierd questions. Any cleaning agent you can flow through the tube that will eat the rust will also prep the wall surface for aggressive corrosion and may cause problems with your brake components. I would look at a mild mechanical cleaning...but how?

Have you ever used a weighted string to clean a gun barrel? Here's an idea: use an air blow nozzle to blow a length of stout binding sting through the brake line. (Gravity ain't going to help you much here unless you work off your roof). Once the string is through, tie a "properly sized" cleaning patch (try 1/4" X 3" long tied in the center to start) to the end of the string, and carefully pull it through the line after saturating the patch with cleaning solvent of choice.

Mineral spirits is probably the best solvent for cleaning the loose rust; however, you will also have to make a pass to clean the mineral spirits off the inside wall using something that won't harm your caliper seals and hoses. Brake fluid is a good choice if you don't have denatured alcohol or commercial brake cleaner.

Getting the patch sized right is of critical importance...get it too small and you won't get good friction on the walls; get it too large, and you could break the cord and loose the patch inside...then this little surface rust is going to be a secondary priority (You could try using the air blow nozzle to BLOW out the patch!).

Until you determine the optimum patch size, you should consider tying the patch about 2 feet from the string end leaving a little tail...that way, if you get the patch too large and it has too much resistance early (plan for the tightest bend), you can still pull the patch out before it travels too far.

When the dirty patch comes through, change the patch, and repeat the process until the patch comes out relatively clean; or, until your patience/enthusiasm evaporates, whichever comes first. You may find that it's not as rusty inside the tube as you feared, but I predict the patches are still going to be dirtier than you thought.

[Tracy C.]

One of Creedence Clearwater Revival's tunes

comes to mind as I read your and that other "Chuckster's" post...I think it was... "I see a bad moon arise'n".

I can just see you yank'in some junked up wad of cotton rag through an "itty bitty" brake line and eventually wadding it up into a nice pretzel shaped configuration fit for the trash can.

Here's another "half baked" idea...good ol'e muratic acid. If you used a pointy tip mustard bottle you could stand on the peak of your roof like previously mentioned and squirt the magic mixture into the pesky tube to clean out the surface rust. Just be sure to flush about 5 times with a baking soda water mixture to neutrualize the acid. Follow up with a brake fluid primer coat.

Suggest loading all bottles with appropriate solutions and taking everything to the roof on the first trip... this will save unnessecary trips up and down the latter later.

But then again Chuck..if this rust thing botters you that much maybe you should just buy a new set of steel brake lines...I think a whole new set will cost less than $100...

This might be a cheaper alternative than going to the trouble mentioned above. At least I know your neighbors won't think you nutty or something.

good luck,
tc

[Tracy C.]

One of Creedence Clearwater Revival's tunes

comes to mind as I read your and that other "Chuckster's" post...I think it was... "I see a bad moon arise'n".

I can just see you yank'in some junked up wad of cotton rag through an "itty bitty" brake line and eventually wadding it up into a nice pretzel shaped configuration fit for the trash can.

Here's another "half baked" idea...good ol'e muratic acid. If you used a pointy tip mustard bottle you could stand on the peak of your roof like previously mentioned and squirt the magic mixture into the pesky tube to clean out the surface rust. Just be sure to flush about 5 times with a baking soda water mixture to neutrualize the acid. Follow up with a brake fluid primer coat.

Suggest loading all bottles with appropriate solutions and taking everything to the roof on the first trip... this will save unnessecary trips up and down the latter later.

But then again Chuck..if this rust thing botters you that much maybe you should just buy a new set of steel brake lines...I think a whole new set will cost less than $100...

This might be a cheaper alternative than going to the trouble mentioned above. At least I know your neighbors won't think you nutty or something.

good luck,
tc

[Dennis C.]

Re: One of Creedence Clearwater Revival's tunes

Totally agree w/tc's final thoughts on this subject. Buy a new set of lines. If you just can't live with that, buy a S/S set. Feel like maybe this issue is being "over analyzed"... Parts is parts, brake lines is brake lines...

[Dennis C.]

Re: One of Creedence Clearwater Revival's tunes

Totally agree w/tc's final thoughts on this subject. Buy a new set of lines. If you just can't live with that, buy a S/S set. Feel like maybe this issue is being "over analyzed"... Parts is parts, brake lines is brake lines...

[Mike Cobine]

One of the best laughs in awhile

I can just picture standing on the roof to clean or the look on a face about the time that patch snags and is forever stuck halfway through. ROFL!!

That rust won't hurt anything. You would be amazed at all the junk that can live in your brake fluid and still stop you from 150 mph.

And if you are still worried, you only need to clean aobut 6 inches of brake line. It is only that last six inches of fluid that goes in and out of the caliper when you are stepping on the brakes. It isn't like oil that is circulating.

But realistically, flush the lines with fluid a couple of times before installing. That should get any dirt laying in there out, and any loose rust. Then after you have the car running, change the fluid in a week or so. That will let whatever is going to be loose and moving towards the calipers get suspend in the fluid. The flush it all out from the MC to the calipers.

Then every year, flush and change the fluid.

Of course, most of the darkness isn't so much from rust as it is from heat. Boil the brakes, the fluid turns dark like mud. And will have about as much stopping power. So if it darkens too much, just flush and change.

[Mike Cobine]

One of the best laughs in awhile

I can just picture standing on the roof to clean or the look on a face about the time that patch snags and is forever stuck halfway through. ROFL!!

That rust won't hurt anything. You would be amazed at all the junk that can live in your brake fluid and still stop you from 150 mph.

And if you are still worried, you only need to clean aobut 6 inches of brake line. It is only that last six inches of fluid that goes in and out of the caliper when you are stepping on the brakes. It isn't like oil that is circulating.

But realistically, flush the lines with fluid a couple of times before installing. That should get any dirt laying in there out, and any loose rust. Then after you have the car running, change the fluid in a week or so. That will let whatever is going to be loose and moving towards the calipers get suspend in the fluid. The flush it all out from the MC to the calipers.

Then every year, flush and change the fluid.

Of course, most of the darkness isn't so much from rust as it is from heat. Boil the brakes, the fluid turns dark like mud. And will have about as much stopping power. So if it darkens too much, just flush and change.

[Terry M.]

Re: One of the best laughs in awhile

I would shoot some aerosol Brake Clean through the lines and call it good. The force of the aerosol will move any loose objects. Follow with a couple of blasts of shop air.

[Terry M.]

Re: One of the best laughs in awhile

I would shoot some aerosol Brake Clean through the lines and call it good. The force of the aerosol will move any loose objects. Follow with a couple of blasts of shop air.

[Chuck R.]

Re: I kinda like the roof thing

The neighbors already think I'm nuts fixing up a thirty four year old car

Hey Chuck, your suggestion brought to mind an application I witnessed in pulling electrical wires in a burried 1" conduit.

A 300' run mind you, he had a little puff ball tied to a spool of 2lb. test fish line. At the other end he had a shop vac.....yep, sucked that sucker through in no time flat! Then it was a matter of stepping up in string size until he had the pulling line he wanted. Not so far fetched there Chuck.

I think I'll go for the brake cleaner and lots of air pressure method.

I also tend to agree with Mike C. in that the fluid is only active within the first six inches on either end and the rest is more filler media.

Thanks guy's and stay tuned for my next question, if anything, just for the comedic value of it

Might come out of right field on the next one

Chuckster

[Chuck R.]

Re: I kinda like the roof thing

The neighbors already think I'm nuts fixing up a thirty four year old car

Hey Chuck, your suggestion brought to mind an application I witnessed in pulling electrical wires in a burried 1" conduit.

A 300' run mind you, he had a little puff ball tied to a spool of 2lb. test fish line. At the other end he had a shop vac.....yep, sucked that sucker through in no time flat! Then it was a matter of stepping up in string size until he had the pulling line he wanted. Not so far fetched there Chuck.

I think I'll go for the brake cleaner and lots of air pressure method.

I also tend to agree with Mike C. in that the fluid is only active within the first six inches on either end and the rest is more filler media.

Thanks guy's and stay tuned for my next question, if anything, just for the comedic value of it

Might come out of right field on the next one

Chuckster

[Chuck S.]

Some Guys ...

Just have no adventure in their souls.

Actually, I got the idea from wire-pulling techniques (and gun cleaning)...typically the string is used to pull a steel wire "fish-tape" through the conduit. I agree that buying new lines might be best if you are really concerned about the rust, but now you've invested all that work on the outside appearance. The time to install new lines is BEFORE body drop...if you haven't dropped the body, it might be worth considering.

Muriatic acid is the obvious answer and the first thing that comes to mind, but I frankly would not use muriatic acid INSIDE a brake system. Neutralization and clean-out MUST be been done carefully, but that isn't my concern long-term...steel cleaned with muriatic acid rusts like a SOB (remember, I said "aggressive corrosion"). If C3 brake systems have a problem with rust (and we know that they do), you could be forced to deal with perennial problems until those old (muriatic acid cleaned) brake lines ARE replaced.

Pouring and blowing may make you feel better, but if you REALLY have anything stuck to the walls, it isn't going to come out in my opinion. The good news is...unless the present rust is significant, it probably isn't going to do much harm. Considerable rust from line corrosion, however, will move toward/into the caliper with each brake bleeding, and then the trouble starts.

[Chuck S.]

Some Guys ...

Just have no adventure in their souls.

Actually, I got the idea from wire-pulling techniques (and gun cleaning)...typically the string is used to pull a steel wire "fish-tape" through the conduit. I agree that buying new lines might be best if you are really concerned about the rust, but now you've invested all that work on the outside appearance. The time to install new lines is BEFORE body drop...if you haven't dropped the body, it might be worth considering.

Muriatic acid is the obvious answer and the first thing that comes to mind, but I frankly would not use muriatic acid INSIDE a brake system. Neutralization and clean-out MUST be been done carefully, but that isn't my concern long-term...steel cleaned with muriatic acid rusts like a SOB (remember, I said "aggressive corrosion"). If C3 brake systems have a problem with rust (and we know that they do), you could be forced to deal with perennial problems until those old (muriatic acid cleaned) brake lines ARE replaced.

Pouring and blowing may make you feel better, but if you REALLY have anything stuck to the walls, it isn't going to come out in my opinion. The good news is...unless the present rust is significant, it probably isn't going to do much harm. Considerable rust from line corrosion, however, will move toward/into the caliper with each brake bleeding, and then the trouble starts.