Brake Warning light

Author Topic: Brake Warning light  (Read 7366 times)

Offline ChallengerHK

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Re: Brake Warning light
« Reply #15 on: March 22, 2012 - 06:15:15 PM »
Mine went out once for about a week, and I was ecstatic. Then it came back. I know the brake system is solid, so I don't lose sleep over it. One day I'll figure it out


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Offline Jamiez

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Re: Brake Warning light
« Reply #16 on: April 07, 2012 - 09:50:06 PM »
Well the car has been up on jack stands for the past few weeks.  I've gone over the lines and everything looks good.  I've cleaned the rear drums and there doesn't appear to be any problems there.  However when I run the car and spin the rear wheels, the brakes don't seem to stop the rear wheels.  The emergency brake stops the rears no problem.

So the mechanics of the brakes work, but there is something wrong with the fluid side of things, either the MC, booster, or prop valve.  I plan to crack open the bleed screws and see if I get any fluid.  Given there's a lot more pedal travel than I remember, I suspect very little/no fluid will come out.

Guess I should start looking for brake parts :)

Offline Chryco Psycho

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Re: Brake Warning light
« Reply #17 on: April 07, 2012 - 09:52:43 PM »
could be a bad hose to the rear diff also , they do not last forever

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Offline Jamiez

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Re: Brake Warning light
« Reply #18 on: April 12, 2012 - 05:44:49 PM »
So now that the master has fluid in it and the temperature has climbed above 40*  I did some more inspecting of the rear drums.

Looks like the problem is the driver's side rear wheel cylinder:


Fluid leaks out of the top (near the boot on the front side) and dribbles down eventually exiting out the bottom of the drum.

So I'm guessing replacement is the way to go

Offline wiging19

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Re: Brake Warning light
« Reply #19 on: April 13, 2012 - 03:56:30 AM »
If you replace one I've always found that it is best to do them all.  Plus replace the lines. That way you know your brakes will work correctly when you put your foot down.  Don't be surprised if your master cylinder goes out shortly after replacing the wheel cylinders.  After years of working with low pressure they tend to go out soon after normal pressure returns to the system.  Sometimes you’re lucky but mentally be prepared if it does happen.  Changing the cylinder and hose lines is pretty easy to do at the same time which is why I suggest doing both together.   Then you only have to bleed the system once.  Growing up my dad tried to just fix them one at a time but it seemed that we ended up bleeding the brakes on weekly bases for the next two months.  So now I just do it in two stages with the second step being changing out the master cylinder if it goes bad.  I like to be thorough but I’m also lazy.  Don’t want to spend time doing things over if I can avoid it.

Offline Jamiez

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Re: Brake Warning light
« Reply #20 on: April 13, 2012 - 06:24:45 AM »
Yeah I ordered 2, with how old they look to be, I'm guessing the driver's side has worn out, and the passenger side probably isn't too far behind.
I'm still up in the air on replacing the lines themselves...I know it probably makes sense to do so but replacing OE stuff that isn't broken kinda rubs me the wrong way

Offline ChallengerHK

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Re: Brake Warning light
« Reply #21 on: April 13, 2012 - 09:56:21 AM »
My car has the original hard lines, and Tony has told me that their "kind of soft." Since I like driving any car hard, replacing those is one of my first priorities.


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

- Han Solo, Star Wars

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Offline Bullitt-

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Re: Brake Warning light
« Reply #22 on: April 13, 2012 - 10:46:58 AM »
Save those old cylinders, you may end up rebuilding them as I've heard the Chinese made replacements have fitment issues.
As for the brake lines I would at least look at replacing the rubber hoses. 
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Offline jhaag

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Re: Brake Warning light
« Reply #23 on: April 13, 2012 - 11:21:13 AM »
For what it's worth, everyone needs to remember that brake fluid attracts moisture. Therefor metal parts can rust from the inside out as well. This is why you have rust and pitting inside wheel and master cylinders. Replacing hard lines when working on the system is a good idea. These cars tend to sit alot and depending on your local weather and storage conditions, contaminated brake fluid is a real possibility. At the very least you should completely flush the system, so you know it is fresh and uncontaminated.
love 70 Challengers

Offline Jamiez

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Re: Brake Warning light
« Reply #24 on: April 13, 2012 - 07:09:44 PM »
So reading the service manual on how to remove the wheel cylinders, it mentions a number of special tools:

C-3785 for the return springs
C-4070 for the retainer springs/nails

Are there alternatives to these tools or are they still available today?

Offline ChallengerHK

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Re: Brake Warning light
« Reply #25 on: April 13, 2012 - 07:14:15 PM »
I have a brake spring tool, and it helps, but it's not all that. the only thing I would call crucial would be goggles.


"She'll make point five past light speed. She may not look like much, but she's got it where it counts, and I've made a lot of special modifications myself."

- Han Solo, Star Wars

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Offline Chryco Psycho

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Re: Brake Warning light
« Reply #26 on: April 13, 2012 - 11:42:39 PM »
the correct tools are common , but you can do it without them , remove the springs with vice grips , install with a std screwdriver just sliding the springs down the shaft of the screw driver over the pins , the retainer sprngs can be removed & installed with pliers easily .

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Offline Jamiez

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Re: Brake Warning light
« Reply #27 on: April 13, 2012 - 11:52:46 PM »
Great! Thanks

Offline wiging19

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Re: Brake Warning light
« Reply #28 on: April 15, 2012 - 05:27:25 AM »
For what it's worth, everyone needs to remember that brake fluid attracts moisture. Therefor metal parts can rust from the inside out as well. This is why you have rust and pitting inside wheel and master cylinders. Replacing hard lines when working on the system is a good idea. These cars tend to sit alot and depending on your local weather and storage conditions, contaminated brake fluid is a real possibility. At the very least you should completely flush the system, so you know it is fresh and uncontaminated.

 :iagree:

Offline Jamiez

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Re: Brake Warning light
« Reply #29 on: April 15, 2012 - 05:53:37 AM »
Per my restoration thread I'll be replacing all the lines and the master. Not to mention the leaking wheel cylinders. It's not the cheapest route but looking at the gunk coming out of the lines, they won't last too much longer.