65 vert brakes went out

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bengill
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Re: 65 vert brakes went out

Unread post by bengill » Thu Jun 29, 2017 12:41 pm

Yeah I hear what you're saying what I think I'm going to do is I want to get it back on the road and then just take my time explaining the rest of the brake lines and replacing them if I see any signs of internal corrosion.


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terribleted
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Re: 65 vert brakes went out

Unread post by terribleted » Fri Jun 30, 2017 9:08 am

Hmmm I am curious as to how much explaining brake lines require:)
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Re: 65 vert brakes went out

Unread post by bbodie52 » Fri Jun 30, 2017 11:23 am

bengill wrote:Thu Jun 29, 2017 2:41 pm

Yeah I hear what you're saying what I think I'm going to do is I want to get it back on the road and then just take my time explaining the rest of the brake lines and replacing them if I see any signs of internal corrosion.
I would suggest that you have already "seen signs of internal corrosion" with your first blowout. You were lucky. The next sign might include an accident — possibly with an injury and/or damage to your car or other vehicles or pedestrians... possibly triggered by hard braking to try to stop in an emergency situation!

:omgosh:
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Re: 65 vert brakes went out

Unread post by bbodie52 » Fri Jun 30, 2017 3:41 pm

The brake system failure that was previously described in this thread has been described as being located in a protected area of the car that is above the fuel tank. This portion of the steel brake line has almost no exposure to water or road salt. If the heavy steel brake tubing has failed in this area, it must be assumed that the failure was likely due to water content in the brake fluid. A high water content would promote rusting and corrosion inside the steel brake line, which would not be detectable with any type of external examination. The lines may look fine on the outside, but the steel line that is being eaten away and weakened by rust and corrosion on the inside will be undetectable until it blows out. Such a failure can have catastrophic results if it causes any kind of collision or loss of control.

The only warning sign that deterioration and decay is occurring inside the brake lines would be system blowout. If the failure occurred in a protected, isolated area of the car, then external physical damage can be ruled out as a cause. If there is no sign of scaling, rust, or corrosion on the outside of the line where the failure occurred, it must be assumed that the line failed due to age and interior damage caused by rust and corrosion that was promoted by contaminated brake fluid with a high water content. Since the steel brake lines throughout the car are likely all the same age and were manufactured utilizing the same gauge and thickness of steel, you can assume that other weak points are developing throughout the system. Although it may be time-consuming and expensive to replace all of the brake lines and flexible rubber hoses throughout the car, the alternative risk would be a high probability of future failure that may cause a serious accident or injury. It would be false economy to gamble by driving such a car when another future failure of the brake system is likely. Another brake line failure would be even more likely during an emergency stop, when the brake system would be exposed to the highest fluid pressures in an emergency application of the brake system. A brake system failure under such circumstances could have terrible consequences.
BRAKE FLUID PREVENTIVE MAINTENANCE

Many experts have long recommend changing the brake fluid every year or two for preventative maintenance. Their rationale is based on the fact that glycol-based brake fluid starts to absorb moisture from the moment it is put in the system. The fluid attracts moisture through microscopic pores in rubber hoses, past seals and exposure to the air. The problem is obviously worse in wet climates where humidity is high.

After only a year of service, the brake fluid in the average vehicle may contain as much as two percent water. After 18 months, the level of contamination can be as high as three percent. And after several years of service, it is not unusual to find brake fluid that contains as much as seven to eight percent water.

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An NHTSA survey found that the brake fluid in 20% of 1,720 vehicles sampled contained 5% or more water!

As the concentration of moisture increases, it causes a sharp drop in the fluid's boiling temperature. Brand new DOT 3 brake fluid must have a dry (no moisture) boiling point of at least 401 degrees F, and a wet (moisture-saturated) boiling point of no less than 284 degrees. Most new DOT 3 fluids exceed these requirements and have a dry boiling point that ranges from 460 degrees up to over 500 degrees.

Only one percent water in the fluid can lower the boiling point of a typical DOT 3 fluid to 369 degrees. Two percent water can push the boiling point down to around 320 degrees, and three percent will take it all the way down to 293 degrees, which is getting dangerously close to the minimum DOT and OEM requirements.

DOT 4 fluid, which has a higher minimum boiling temperature requirement (446 degrees F dry and 311 degrees wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. Three percent water will lower the boiling point as much as 50%!

Considering the fact that today's front-wheel drive brake systems with semi-metallic linings run significantly hotter than their rear-wheel drive counterparts, high brake temperatures require fluid that can take the heat. But as we said earlier, the brake fluid in many of today's vehicles cannot because it is old and full of moisture.

Water contamination increases the danger of brake failure because vapor pockets can form if the fluid gets too hot. Vapor displaces fluid and is compressible, so when the brakes are applied the pedal may go all the way to the floor without applying the brakes!

In addition to the safety issue, water-laden brake fluid promotes corrosion and pitting in caliper pistons and bores, wheel cylinders, master cylinders, steel brake lines and ABS modulators.
:link: http://www.aa1car.com/library/bfluid.htm
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Re: 65 vert brakes went out

Unread post by 66vairguy » Fri Jun 30, 2017 6:00 pm

Brakes are a safety item and shops are paranoid about fixing just one thing and then the car is back for another unrelated leak. Also the guy makes move money "doing it all".

I'd suggest asking him to show you were the leak is. If it is the line above the gas tank - well yes the tank has to come out (that's why nobody ever replaces that line). With plumbing you try to remove one part and it's frozen to another - etc. Mechanics hate quoting a job only to have to call back and say "We found another part that needs replacing", it annoys the customer and makes them wonder if the mechanic is competent. So your shop is probably quoting replacement of everything from the MC to the front wheel cylinders.

Bottom line - when I get an old car I replace ALL the brake plumbing, hoses, and cylinders - then I don't worry about what's going to let loose next. I have the time so it's only parts that cost me.

You'll have to decide what you want to do based on your circumstances.

bengill
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Re: 65 vert brakes went out

Unread post by bengill » Fri Jun 30, 2017 10:24 pm

66vairguy wrote:Brakes are a safety item and shops are paranoid about fixing just one thing and then the car is back for another unrelated leak. Also the guy makes move money "doing it all".

I'd suggest asking him to show you were the leak is. If it is the line above the gas tank - well yes the tank has to come out (that's why nobody ever replaces that line). With plumbing you try to remove one part and it's frozen to another - etc. Mechanics hate quoting a job only to have to call back and say "We found another part that needs replacing", it annoys the customer and makes them wonder if the mechanic is competent. So your shop is probably quoting replacement of everything from the MC to the front wheel cylinders.

Bottom line - when I get an old car I replace ALL the brake plumbing, hoses, and cylinders - then I don't worry about what's going to let loose next. I have the time so it's only parts that cost me.

You'll have to decide what you want to do based on your circumstances.
Thank all of you guys for your help. I have ordered new brake lines from Clark's as well as new hoses so once I get those installed I'll have them do a complete flush and refill with silicone fluid


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bengill
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Re: 65 vert brakes went out

Unread post by bengill » Fri Aug 11, 2017 7:16 am

Update... got all steel lines replaced as well as rubber lines. All good to go!


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Hard, Harder, Hardest Brake Test

Unread post by azdave » Fri Aug 11, 2017 9:15 am

Since this thread has come back to the top it's a good time to remind everyone of a quick, simple test that can save your life.

The very first thing you should check daily before ever starting the engine on any old car is the brakes. The best place to test your brakes is always in your parking spot with the E-brake engaged. Many classic car people use the "Hard, Harder, Hardest Brake Test".

I have trained myself and my wife to always check the brakes before ever turning the ignition key. Normal brake pressures during daily driving is low compared to pressures seen during a panic stop. Rust can eat away the steel lines in places you can't see so a pressure test each day is a good way to make sure they are up to the task. Press hard, then harder, then hardest. You won't hurt the brakes but you may save serious injury to you or others.

If the brake lines and cylinders hold pressure under a stressful test condition like that then they are very unlikely to fail under normal driving conditions on the road. Be sure to check the brake fluid level and condition of the brake fluid in the master cylinder at least every three months.

I'm sure the OP's car would have failed this test weeks or even months prior to the incident. Think of how long he drove around on the edge of a possible disaster. His brakes failed while driving 5 MPH. Also, don't feel secure and ignore brake maintenance just because you have a dual master cylinder installed. Even with a properly operating dual MC it takes much more distance to stop when one circuit fails.
Dave W. located in Gilbert, AZ
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toytron
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Re: 65 vert brakes went out

Unread post by toytron » Fri Aug 11, 2017 10:09 am

That is great info Dave! On a side note. I drove my daughter's focus home after her graduation from college and felt that I should do her brakes while she went on to her AIT (military training) well the day that I decided to do it I needed to back her car up so I had room for the Jack. When I started to back up I put on the brakes and they went to the floor. Before I could use the parking brake it hit the front of the wife's car. No damage but when I jacked up the car I noticed one of the front pads was on the ground. After taking off the front brakes I found that all four pads had separated from their metal backing. I have never seen that before. I am thankful that I was the one who drove her car home. But back to this topic. I have a small help for Master cylinder replacement. If you do not disturb the brake lines too much when you remove the old master cylinder. Bench bleed the new one and carefully install it back on the car with the lines off. Place a rag below it and have someone gently press the pedal fully and hold it. Reattach the lines and let the assistant release the pedal. If done properly any possible air in the line will have been pulled into the reservoir. I learned this years ago when I worked as a mechanic. If there is no pedal fade or spongeness then you should be good to go. If the pedal does not feel right then you will bleed the system as normal.

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