Brakes stuck on

Z

zzpw3x

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I have a 2004 LS with the V6.

The car is stuck in my driveway with the brakes on. I pushed the brake pedal down to shift into gear and the pedal didn't come back up all the way and the car won't move. The brake lights are on too.

I don't think this is not a parking brake issue or a transmission issue. The suspension loads when I try to move. The car wants to move but the brakes are being applied preventing smooth movement.

Any ideas? I would not think that the master cylinder would prevent the break pedal from returning to its normal position. I tried pulling it up by hand and it would not move. Could it be the brake booster?

Thanks,

Dale
 
If it was the booster, I don't think the brake lights would be on. I think that maybe something under the dash is jamming the pedal down. I'd look there first.
 
Thanks for the quick response.

I disconnected the brake pedal from the booster rod and the pedal moves freely but the brake booster rod is "in" about 1/2 inch. It seems to be what was holding the pedal in the down position (and why the brake light is on).

The rod is connected to the brake booster, right? Is there a rebuild kit for this or do I need to get a new brake booster? I looked on rockauto for a kit and didn't see one but maybe they are out there somewhere.

Dale

I have the shop manuals. It looks mostly straight forward, but if anyone has any good tips, they will be appreciated.
 
I don't know of any rebuild kit for the brake booster. You'll have to buy another one (new, used, or maybe rebuilt).
 
I'll start by saying that I don't understand how a brake booster works.

Is there a check valve or something that wasn't allowing the brake booster to release the vacuum when the pressure (my foot) was let off?
 
There is a big diaphragm in the middle. Engine vacuum is applied to both sides of it. There is a check valve in the vacuum line from the engine so that if engine vacuum falls, the booster will remain a high vacuum until it uses it. (There is also a two way valve so that if engine vacuum is low due to the throttle being wide open, vacuum from the venturi effect of air moving at high speed through the intake is used instead.)
Anyway, when you press on the brake, a valve inside the booster in the middle of the diaphragm is activated. It blocks vacuum to the back side of the diaphragm and vents air into the back side. The force of the air on the back side against the vacuum on the front side moves the diaphragm towards the front of the booster. When/if it moves far enough forward, there is no longer any pressure on the valve, so it stops venting air in. When you release (or just ease up on) the brake, the valve is no longer pressed at all, and it allows vacuum from the front side back into the back side.

There's probably a good animation on how it works somewhere on the web.
 
????? My own '02 LS V8 operates the brakes by the use of a 'hydro-boost'-type system. Everything is hydraulic. Am I missing something?
(BTW, 'hydr-O-boost' seems to be a generic motors sort of spelling. A really good example of the lack of intellect in the other camp, since ...hydro... implies something to do with water.)

KS
 
cammerfe said:
????? My own '02 LS V8 operates the brakes by the use of a 'hydro-boost'-type system. Everything is hydraulic. Am I missing something?
(BTW, 'hydr-O-boost' seems to be a generic motors sort of spelling. A really good example of the lack of intellect in the other camp, since ...hydro... implies something to do with water.)

KS
Click to expand...

Are you sure about this? I've never heard of an LS with a hydraulic booster. I also don't see one anywhere in the Ford parts lists, only vacuum boosters. Please post a picture of your setup (master cylinder and booster).
 
Are ALL the tires locked (jack it up and check)? If so it sounds like you might have dirt or rust in your brake fluid and it's plugged the master cyl. If that's the case try bleeding your brakes to flush out all the old fluid.
 
OP....I have a brake booster and master cylinder for sale if you need them. Came off of an 06 LS. PM me if you want
 
hite337 said:
OP....I have a brake booster and master cylinder for sale if you need them. Came off of an 06 LS. PM me if you want
Click to expand...

Note that it has to match up as - Either both cars have/had AdvanceTrac, or neither did/do.
 
joegr said:
Are you sure about this? I've never heard of an LS with a hydraulic booster. I also don't see one anywhere in the Ford parts lists, only vacuum boosters. Please post a picture of your setup (master cylinder and booster).
Click to expand...
Lincoln introduced the Hydro Boost on the 1974 Continental. I think GM originally introduced the system many years before. It uses pressure from the power steering system for assist and can provide higher and more reliable braking power. It's likely the LS with AdvanceTrac and BrakeAssist would have it.
 
Robot said:
Lincoln introduced the Hydro Boost on the 1974 Continental.
Click to expand...
I have a friend whose brother rebuilt a few Mercury Comets & a popular mod was to grab the Hydroboost setup from a 70s Lincoln. Quick internet search found this pic:

VancoHydroboostLg.jpg

Whether or not an LS equipped with Brake Assist uses something similar I cannot say.

VancoHydroboostLg.jpg
 
Yes, I know about the earlier Lincolns with it. The LS doesn't have it. It's vacuum. All you have to do is look at your LS.
 
i see peeps posting in other areas, but yet to post up the hydro boost
set up on his ls..

as joe says, the ls has a vacuum boost set up. all you have to do is lay
your eyes upon it, and it will show truth ;)
 
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