Brake Line Repair

[Guest rsd9699]

I have a question and I turn to you guys and gals for answers.

I have a 78 3/4 ton Chevy that I am having brake problems with. The valve that controls the rear wheel application first and warning light is malfunctioning. The brake warning light will not reset after a number of brake bleedings. I want to replace the valve and have gotten the replacement valve but the fittings are rusted solid to the original valve to the point I have rounded one nut. So time to take a break and let the penetrating oil do its trick while I call in the reinforcements.

I have tapped, hammered but not pounded the nut. I have heated it and iced it in attempts to break the rust barrier. No luck after several attempts over a period of months.

Do I cut the lines? If I do, can I use compression fitting or go the inverted double flare way. Is one safer than the other?

Many thanks for your comments.

Ron

[Guest Silverghost]

All brake lines MUST be double flared .

It's the only safe way to go.

Too much pressure for any other style of fittings.

Compresson fittngs never belong on brake lines !

They will not hold back this extreme pressure in a brake system.

Are you using flare nut wrenches ?

They are designed to remove flare nuts without crushing them.

They hold the nut properly on five sides.

Sears Craftsman sells them as do others.

Do not heat the flare nut fitting...

Just the defective valve itself !

On some of these warning valves there is a small re-set pin on the end to re-center the brake warning switch.

If you have such a pin lightly tap it to it's center position to re-set the brake warning light & turn it off !

I suspect it may be stuck and corroded in the brake warning position !

These are designed to indicate that pressure is low on either the front or rear 1/2 hydraulic system.

Good Luck .

Edited October 14, 2010 by Silverghost (see edit history)

[Fr. Buick]

Flare nut wrenches are the way to go, but it sounds like even that might not do it. The problem is that the nut rusts onto the line itself.

You may have to cut the line to get the nut off. But then the best bet is to replace the whole line. If there are rust problems in the valve and switch, it may be time for the sake of safety.

Try one of the brake-line companies - they make stuff pre-bent and flared and ready to go for an amazingly broad line of cars and trucks.

And on a truck, it would be much easier to remove and replace something like this, I would think.

Good luck, and be sure to check five times for any leakes once it is done,

Doug Cook

[Guest rsd9699]

Thanks for the replies received so far.

I have used both metric and sae line wrenches - neither fit the way I would prefer - too loose to start with. In fact, I have not found a wrench that does fit and I have us name brand made and foreign made tools that I have tried.

I have heated the cast iron valve not the line nuts themselves.

On both valves, there is a rubber boot that covers something on one end. Is this the reset pin?

I am sure the one line will need replacement. Is the brake line kit available for the box parts stores or special order?

I was pretty sure that flared was the way to go but oreally people were telling me cut it and use compression fittings. I do not have a truck manual but my pre disk brakes Olds manual said cut and double flare was the only way to go. I wanted to be sure - if it sounds too good - then it is likely a sales line......

Is a flare nut wrench or a line wrench not one and the same and that is the reason for the loose fit?

Ron

[R Walling]

Whenever I work on a brake line that gives me trouble, I change the line for a new one PERIOD! If one end is bad, so is the other end!

After all work is done and the brakes are working fine, I step on the brake with two feet and hands on the steering wheel and try to rupture any other lines that may be weak. If I do break one, I am thankfull that it happened in the shop, not on the road.

[Larry Schramm]

I agree with new lines. Just did a car that it seemed that everything I touched in the back started leaking. I finally just cut all of the lines under the drivers seat and replaced everything back.

Remember, If you cannot get it started you can not get into trouble. If you can not stop, you are in trouble.

[Rusty_OToole]

Compression fittings are not good enough for brake lines. This is one of those hillbilly fixes you can get away with, sometimes, as long as you don't use the brakes hard or ever need to make an emergency stop. Not something to bet your life on or the lives of your loved ones.

Cut the brake line off flush with the nut, use a socket wrench to take off the fitting, and fit a new brake line. They are not at all expensive especially if you value your life and the lives of other road users. You can replace all the hard lines on your truck for under $50 bucks. Universal or straight lines from the parts store are fine. Take the line you cut off, measure it for length, and use it as a pattern to bend the new line.