brake acceleration

[lorraine1]

on a 98 explorer,5.0, i went to stop and when i pushed the brake pedal it accelerated an i couldnt stop,WYF!any ideas what would cause this?it has auto tranny.

 

[koda2000]

on a 98 explorer,5.0, i went to stop and when i pushed the brake pedal it accelerated an i couldnt stop,WYF!any ideas what would cause this?it has auto tranny.

This has happened to me several times. It's because I hit the gas pedal and brake pedal at the same time (I have big feet). I've learned to be very deliberate when moving my foot to the brake pedal.

 

[lorraine1]

thats not what happened here,i had the brake pedal mashed only,100 percent sure.

 

[koda2000]

thats not what happened here,i had the brake pedal mashed only,100 percent sure.

Well, I have no other thoughts. I can think of NO situation/condition where stepping on the brake pedal would cause a vehicle to accelerate. If you had a vacuum leak in your power brake booster it could cause a slight increase in RPM, because you're allowing air into the engine which leans the air/fuel ratio. If this is your case you would also notice an increase in RPM while stepping on the brake pedal while idling in neutral and probably poor braking.

 

[SoNic67]

Probably initially it brake, but then the brake gave up and you start to move again. You had the feeling that you are "accelerating" because you where decelerating before.

The brakes are failing, go check them.

 

[Runnin'OnEmpty]

Unintended accelleration.

This happened to me a while back, with an 04 Ranger.
I've also read several posts about it, with other Fords.

I suspect it's something to do with the cruise control;
possibly associated with the BOO switch located on the
master cylinder.

 

[lorraine1]

empty i think you might have hit the nail on the head as they say,i replaced that switch awhile back after it tried to catch fire,and i suspected it might be it as the truck has never done this before and it was the last part installed for a while.i think i replaced it a year ago,advance auto junk.

 

[koda2000]

empty i think you might have hit the nail on the head as they say,i replaced that switch awhile back after it tried to catch fire,and i suspected it might be it as the truck has never done this before and it was the last part installed for a while.i think i replaced it a year ago,advance auto junk.

That switch turns OFF the cruise control. It's called the CC Deactivation Switch. When it leaks it shorts out the switch and, in my experience, the cruise control will not turn ON. I suppose it may be possible if the switch failed in a different way it might not turn the CC OFF, but I don't see how it could turn the CC ON.

OP, had you been using the CC when this happened? If so I agree that this could very well be your problem. Until you get a new switch I'd would immediately disconnect the old one.

 

[lobo411]

Why would you replace the cruise control switch on your own dime when it has been recalled by Ford? Just take the vehicle to the dealer. Besides, at least on mine, they didn't just replace the switch. Looks like they also rewired the circuit, probably because just replacing the switch is not enough to fix the problem.

 

[1997XLTRollover]

Why would you replace the cruise control switch on your own dime when it has been recalled by Ford? Just take the vehicle to the dealer. Besides, at least on mine, they didn't just replace the switch. Looks like they also rewired the circuit, probably because just replacing the switch is not enough to fix the problem.

I think that's because over time the brake fluid can eat away the wiring so they do an entire pigtail.

 

[lorraine1]

well around here they (ford) refuse to replace this switch,and forcing them to do this is useless as they wont and this was an old recall.

 

[lorraine1]

scratch last post,i talked to ford and they are going to replace the switch,there is another recall also,i believe it was a seat recliner bolt,crs,i think on the last one.this is the best info site out there,thanks guys for the help.

 

[koda2000]

scratch last post,i talked to ford and they are going to replace the switch,there is another recall also,i believe it was a seat recliner bolt,crs,i think on the last one.this is the best info site out there,thanks guys for the help.

Yep. I had my dealer add the pigtail on recall and do the seat bolt recall. 3 weeks later my CC deactivation switch started leaking and they replaced that too. I believe the recall for the cruise control technically stated that the pigtail was added to prevent overheating/fires and that they would replace the CC deactivation switch at the same time, but only if it was leaking. I had to argue changing the switch on recall, because it wasn't leaking when the pigtail was done, but they eventually gave in after I told them I found it strange the switch was fine for 206,000 miles and only started leaking a few weeks after they disturbed it. If you have to buy one, they're around $30 on eBay.

 

[swshawaii]

Here's Ford's safety recall:

http://www.phila.gov/fleet/Warranty Recalls/Recall 09S09.pdf

 

[SoNic67]

Why would you replace the cruise control switch on your own dime when it has been recalled by Ford? Just take the vehicle to the dealer. Besides, at least on mine, they didn't just replace the switch. Looks like they also rewired the circuit, probably because just replacing the switch is not enough to fix the problem.

They added a fuse on that circuit. Did it on mine too.