brake/Shift thing whats up?

viiiball

Registered
Somthing kinda funny has been happening lately,I am assuming our cars are like most others in the way that the brake needs to be pressed before you can put the car into gear with the shifter,well i push the brake and the shifter will not move ....until i figuered it out(in the bank line after i held up traffic and pissed off a lot of folks)the shifter seems to working opposite now, I depress the shifter button,then push the brake and it lets the shifter free,whats up? and whats the fix? no problem yet but don't want it to freeze up on me again especially in a drive tru...a busy one!
 
RE: brake/Shift thing whats up?

That's an odd one. I can really see no way for it to get screwed up like that, so that you have to push the shifter button first.

The only thing i can suggest is checking/replacing the switch on the brake pedal. Mine went bad not too long ago, it wasn't too expensive to replace. When it went out the cruise control didn't shut off immediately when i touched the brake, and the shifter wouldn't shift out of park. Not to mention the brake lights not working properly.
 
RE: brake/Shift thing whats up?

I may go ahead and replace it just to be safe...do you know what it is called and appx. the cost?is it a easy job and whats the easiest way to do it.
 
RE: brake/Shift thing whats up?

Let me guess... brake switch. Final answer.

About $20 at dealer.
http://mark8.org/users/driller/pics/BOOswitch.jpg

From the manual:

Brake-Shift Interlock

A shift interlock mechanism is used on Mark VIII vehicles with an automatic transmission. This is to prevent shifting the transmission out of the PARK position unless the brake pedal is depressed. The system consists of a solenoid assembly attached to the key interlock assembly, a bracket retaining the solenoid, and the necessary wiring. The solenoid is energized when the ignition key switch is turned to the RUN position, locking the shifter in the PARK position. When the brake pedal is depressed and the stoplamp switch is activated, the shift lock solenoid is deactivated and the shifter can be moved out of the PARK position.


----------------------------

Stoplamp Switch, Mechanical

The mechanical stoplamp switch assembly is installed on the pin of the brake pedal arm, so that it straddles the master cylinder push rod. The switch assembly is a slip fit on the pedal arm pin, and the switch pressure plate mates with the flat on the master cylinder push rod. The switch assembly travels with the pedal arm but maintains alignment with the flat on the push rod at all times.

The brake pedal arm pin and plastic bushing has a designed in clearance with the eye of the master cylinder push rod. Because of this clearance, whenever the brake pedal is pushed forward, the stoplamp switch frame moves forward pulling the whole assembly forward. During that movement, the push rod flat pushes the switch pressure plate and actuating pin rearward, closing the switch contacts. This completes the circuit to the stoplamps.

When the brake pedal is released, the spring in the stoplamp switch returns the actuating pin to its normal position and the circuit to the stoplamp opens.


Removal

1. Disconnect the wire harness at the connector from the switch.

NOTE:
Locking tab on connector must be lifted before connector can be removed.


2. Remove the hairpin retainer, slide the stoplamp switch, the push rod and the nylon washers and bushing away from the pedal, and remove the switch by sliding the switch up/down.

NOTE:
Since the switch side plate nearest the brake pedal is slotted, it is not necessary to remove the brake master cylinder push rod and one spacer washer from the brake pedal pin.


Installation


1. Position switch so that the U-shaped side is nearest the pedal and directly over/under the pin. Then slide switch up/down trapping the master cylinder push rod and blade bushing between the switch sideplates. Push switch and push rod assembly firmly toward brake pedal arm. Assemble outside white plastic washer to pin and install hairpin retainer to trap whole assembly.

CAUTION:
Do not substitute other types of pin retainers. Replace only with production hairpin retainer.


2. Assemble the wire harness connector to the switch and install the wires in the retaining clip.

3. Check stoplamp switch for proper operation.

NOTE:
Stoplamp switch wire harness must have sufficient length to travel with switch during full stroke of pedal. If wire length is insufficient, reroute harness or service as required.
 
RE: brake/Shift thing whats up?

Online I use the Ford CD which is the same as the Helms/Ford Factory Service Manual which I also have. Add to that the Helms/Ford EVTM, another generic CD, AllData account, parts listing(pdf & paper), wiring diagrams, brochures and the venerable owner's manual.

What I'd really like to have is a good EEC manual.
 
RE: brake/Shift thing whats up?

what exactly do iask the parts dept. for? and what tools will I need? thanks
 
RE: brake/Shift thing whats up?

I have a similar problem - my switch is OK but the wires leading to it are very brittle. one broke off and I have been unable to reliably splice it becasue it is so old.

94 Mark VIII, Black / Black
dynoed at 247.5hp / 259.7ft-lb!
 
RE: brake/Shift thing whats up?

I am not too bright here what is a leatherman?can i do this in my garage?

http://www.leatherman.com/ :) (Everybody needs one!)

As far as doing it in the garage... you'll most likely need to have the driver's door fully open so you can squirm under the steering column to the brake switch mounted to the brake pedal. If you have room for that you got it made in the shade.
 
RE: brake/Shift thing whats up?

FYI when replacing please be careful not to break any of the wires in the harness,like i did i had to buy a new set (7.50)and cut splice and sodder together.....but it all works now!!!
 
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