Re: [AMC-List] Brake light proporitoning valve question

["Swygert, Francis G MSgt 436 CES/CECM" <Francis.Swygert3@xxxxxxxxxxxx>]

Artie, did you bleed the brakes recently? If not, do you have a leak in
the brake system? The brake valve has a pressure differential switch in
it. If the pressure on one side of the switch (front or rear brakes)
drops the switch slides over and turns the light on. Bleeding the brakes
will "trip" the switch. 

I know a lot of people will call this a "proportioning valve" or a
"combination (combo) valve". Pre 71 AMCs used the same junction block
and switch as drum brakes (pre 66 don't have a brake light switch at
all). If it came with disc brakes there is a separate proportioning
valve near the rear axle in the line (67-70 -- 65 and 66 models used a
lower stopping power non-servo rear drum brake assembly instead).
Sometimes people forget that things used to be done differently!

Of course your car could have been upgraded to a later system. The pin
is on those as well. You can find the procedure outlined in the 73 TSM
on-line at
http://www.tocmp.com/tOCMP/chassis/amc%20site%203/indexold.html. If
yours has the original, follow the instructions for drum brakes. If a
newer model combo valve, for disc brakes. Basically, you need to remove
the plunger in the center (drum/early disc), step on the brake pedal
hard, then reinstall the plunger. It should center and turn the brake
light off unless there's a problem with the brakes and pressure isn't
equal on both sides. It won't leak from the switch hole unless the
switch is bad. The newer type combo valve will reset itself, and the
switch doesn't need to come out for bleeding. 

The manual refers to a "metering function". Unless you have the type
combo valve with metering (mostly 71-78 big cars), ignore it. A combo
valve with metering will have a line to each front wheel from the valve.
Those without (the most common) have a T in the line from the master to
the valve for the left front wheel with the right wheel only connected
to the valve. Metering prevents pressure from going to the front brakes
until enough pressure has built up to overcome the springs in the rear
drum brakes (~100 psi). This way all four brakes engage at the same
time. Early small cars (71-~75) used metering in the combo valve, later
ones don't. Few modern cars use the metering function in their combo
valves.


> ----- Original Message -----
> From: A.F      schurst@xxxxxxxxxxxxx
> To: eddiestakes@xxxxxxxxxxxxxxxxxxxx
> Sent: Thursday, December 28, 2006 11:05 AM
> Subject: Brake light
>
>
> Hello ,
>         I have a SC/Rambler and the brake light is constantly on ( I
> know I could unplug it-or tape over the light) . Do you have or know
> where I could get a brake proportional valve or can they be opened
> and repaired. I recalled reading something about a repair kit. The
> brakes do feel a little biased to the front. Any help would be
> great. Keep up the humor, I had people at work crying over that
> Black beauty AMX partout on Ebay.
>  Thanks Artie Foley

_______________________________________________
AMC-List mailing list
AMC-List@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list

or go to http://www.amc-list.com