Ford Mustang Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
124 Posts
Discussion Starter #1
:?:I have read on this forum that the brake system needs to be bled so as to re-center the plunger in the Distro block. I bled all the brakes in the normal sequence and the light still stays on when the engine is running. I was also told to open all the bleeders and sharply depress the brake pedal and force the fluid from all brake cylinders. This still didnot reset the piston. Does anyone have an ideas on how to get the piston re-centered or do I need to replace the Distro Block? Any and all help would be appreciated to correct this problem.:worship
 

·
Registered
Joined
·
831 Posts
I could be wrong, but isn't that light to warn you about the emergency brake being on? On a modern car, that light usually means the bowl is low on fluid but I doubt the 67 had such a warning system on it.
 

·
Registered
Joined
·
124 Posts
Discussion Starter #3
This light is supposed to notify you about a brake fluid leak in either the front or rear brakes. The Master Cylinder has 2 bowls which the front is fro the front brakes and the rear is for the rear brakes. If the brakes are lost to the front then the plunger in the Distro block moves forward to block the fluid from escaping thru the leak to the front brakes and diverts the oil to the rear brakes so that you do not loose all your brakes. When the plunger moves in the direction of the leak, a metal tab that is in the switch causes a connection in the light circuit and the warning light in the dash comes on. I have tried bleeding the brakes as stated in the initial post but the plunger did not reset itself to the neutral position stopping the completed circuit to the dash light. This light is not used as a low fluid indicator. I have done everything that I have I read in this forum and what is listed in the shop manual, but still have the light lit.
 

·
Registered
Joined
·
17 Posts
have you tried to return the plunger to the middle by loosening the lines to the oposite side of the distribution block that had the leak that caused the bore to move? basicly do the same thing that caused it to move but in the other direction
 

·
Registered
Joined
·
124 Posts
Discussion Starter #5
I would but the plunger was already activated prior to me buying the Mustang. The PO was not aware that the plunger was tripped when he bought the car. No one would know that it was tripped until they located the wire to the switch on the Distro block and plugged it back in. The light comes on initially when the car is started as part of the light checks in the dash and then goes off. I am still open for any suggestions.
 

·
Registered
Joined
·
44 Posts
I had the same thing with my 67 coupe, looking under the hood after bringing it home for the first time, plugged the connector on to the dis block and the light would stay on. I know there are very smart people on this site who will be able to tell you exactly how to do it yourself. In my case the shop were I had
my car serviced removed the dis block and soaked it overnight and then were able to move the plunger to the center position, they have a knack of getting stuck after 40+ years, so I've been told. Hope this helps.
 

·
Registered
Joined
·
4,555 Posts
Recentering the plunger requires two people, one to press the brake pedal hard the the other to open a bleeder valve easy on the front brakes or the rear brakes, the person on the brake pedal must watch the light, and tell the person opening the bleeder valve when it goes out, there is no way to tell whether you need to do the fronts or rears first, just pick one. If you picked the fronts and you couldn't get the light to go out try the rears, don't just pop open the bleeder valve like when you bleed them, open it slowly, when the light goes out, close the bleeder valve and stop. Then press the brake pedal hard and see if the light stays out, this light switch in on the distribution block by the MC. Good Luck.
 

·
Registered
Joined
·
831 Posts
I learn something new every day. Just yesterday I started putting my shoes on after I put my pants on.
 

·
Registered
Joined
·
124 Posts
Discussion Starter #9
Thanks for the information. I'll give it another try. I had a guy suggest taking the switch out of the Disto block and centering the plunger that way. I'll give anything a try. The other mechanic stated that in most cases, individuals usually just leave the switch unplugged because by the time that the light comes on, you already know that something is wrong with the brakes. I'm just a stickler about having things work the way that they are supposed to work. Just me.:kooky:
 

·
Registered
Joined
·
1,630 Posts
I also suggest taking the switch out when trying to center it. The switch plunger does stick or the switch could even be bad. It's easy to remove and inspect.

My 68 had the switch plunger broken off and the plastic case was cracked, it needed a new switch. You don't know what has been done to it in the past.
 

·
Registered
Joined
·
3 Posts
'67 frustrations

I recently joined this forum trying to find Nylon door window rollers. I've had no luck finding any so I used the drawing one of you people made for a replacement (modifying the rivet dimentions to original) and found a small machine shop here in Boise and had them made.
Figuring out the wiring on my '67 coupe has been a challenge because of the weird "wiring diagram manual" and trying to reconcile it with the "3WD-390" diagram which shows all but the differances for things like air conditioning, the dual brake warning lite, and the seat belt warning lite.
Thanks to this forum I now understand the brake warning lite. If any one is interested I'll give the name of that shop that made the nylon rollers.
 

·
Registered
Joined
·
582 Posts
The distribution block has a brass slide valve inside that, as previously stated, is designed to shut off one end of the brake system if a pressure leak is detected (commonly happens when the system is being bled). As it slides to one end or the other, it pushes an arm up to set the brake light switch mounted on top of the block. You can generally remove the switch and reset the slide valve with a pick if the valve is not frozen in place; otherwise, you will have to remove the block, disassemble it and remove the slide valve by hand. Soaking the valve in a solvent overnight will generally loosen the valve, but you MUST then replace the two small O-rings on the slide valve. Solvents will oversoften the O-rings and the system will fail.
The system is a real PITA, but, if you want good brakes, you must follow the rules.
Best,
Al
 
1 - 12 of 12 Posts
Top