98 brake issue.....

[mountainman1]

well we had our first snow last night and woke to a land of white everywhere....so i start up the trusted mountaineer and head out to work....a dip stick pulls out in front of me and i have to hit the brakes....the truck slows down and i miss the dip stick...but when i hit the break pedal to stop ....i hear a squeal from under the dash...i think...wtf...so i go to a parking lot and hit the brakes a few times...and each time i do so i hear the squeal from under the dash.....never had this with any other ABS brake system i have had..but this only happens on the slippery roads or the parking lot...when i had just wet road i hit the brakes...nothing...it just stopped...after work i tried it again in a lot that was not plowed...samething...SQUEAL...any ideas from ANYONE on this....no lights are on in the dash cluster for the ABS.....

[shorod]

Does the ABS seem to be working normally, or do the wheels lock up? How long does the squeal last, just for a fraction of a second when you're pressing the brake pedal or the entire time the ABS is active? Could it be a lubrication issue with the brake pedal that you only hear during a panic stop, while aggressively pressing on the pedal?

-Rod

[mountainman1]

Originally Posted by shorod

Does the ABS seem to be working normally, or do the wheels lock up? How long does the squeal last, just for a fraction of a second when you're pressing the brake pedal or the entire time the ABS is active? Could it be a lubrication issue with the brake pedal that you only hear during a panic stop, while aggressively pressing on the pedal?

-Rod

well Rod...it's only like 2 seconds at the most everytime i hit the brakes on the snow or ice...never when i drive on dry or just rainy roads and hit the brakes....the ABS seems to be working fine...i had a friend drive the truck since i thought i was going nuts...he heard the same thing.....now last night and today when i took the car out after it sat for awhile...i get maybe 100 feet from the house and the squeal noise sounds for a 2 second blast...almost like the door chime box is fadeing sound...but a squeal...the brakes work fine...but i have this noise and i'm not taking it in to a MERCURY or FORD shop ...and have them charge me 100.00 or more to look at it.....i tell ya...it's a freaky squeal.....we have snow coming tonight...so tomorrow i know i'll have the noise again.....

[shorod]

So the time you got about 100 feet from the house and it made the noise, were you pressing on the brake pedal at that time? If not, that would rule out a dry brake pedal linkage. Since the duration of the noise seems consistent every time it would likely be something electric. I'm thinking a pump somewhere, and probably the ABS pump motor.

I suppose it could also be the Secondary AIR pump since that will run through a self test cycle which might occur about the amount of time that you would drive 100 feet, but I don't see a correlation to braking unless that AIR pump also runs when the throttle closes or something. I'm not well versed in the function of the Secondary AIR system.

-Rod

[mountainman1]

well we just got done having MORE snow...and can't handle the noise anymore in the slippery driving conditions....took it to the dealership again...this time...they said the brake booster has a leak and that is what is making the noise.... ...so if the brake booster is bad...wouldn't the brakes be junk all the time or have a hard pedal....i have none of the above..but they say i have a bad booster...time to rebuild the mountaineer and fix it up...so last night the wife and i picked up a '01.......pretty loaded with options comapred to the '98.....and low miles.....

[rhandwor]

Every bad break break booster I changed leaked and the engine ran badly from the vacuum leak.