brakes making horrible noise - ABS?

[Hoot]

guys,

i have a problem i cant diagnose. like many of you who are in the cold weather climate we here in southeastern michigan got dumped on big time. the disco was sweet in the snow and i had no worries driving through it at all. Until i needed to stop. if i apply slow and light pressure to the brake it does just fine but if i apply any amount of full pedal extension pressure on it it makes a horrible shuttering sound and shakes the piss out of the front left side of the truck. it is coupled with a sort of crunching grinding sound and then once that stops it makes an electronic sounding whining noise. does anyone have any idea what this is or how to diagnose it further? this is dangerous as hell and i need to rectify asap.

thanks in advance.

i forgot to say i am driving a 1996 Disco

 

[singingcamel]

Stop driving it ,get it on a lift and have a peek, could be as simple as a ice bugger..or a bad wheel bearing.

 

[Hoot]

how would i diagnose if it were a bad wheel bearing?

 

[ptschram]

It's a bad wheel bearing.

Jack up the wheel, grab it at 3:00 and 9:00, push in at 3, pull at 9. Do the same at 12:00 and 6:00. any movement in the 12-6 plane is bad and likely wheel bearings, movement in the 3-9 plane could be just as bad but tie rod ends.

I'm only a few hours away if you need me to fix it.

 

[Hoot]

i will check it out

 

[Hoot]

update. i pulled the ABS fuse from the fuse panel under the dash and the brake problem ceased. put it back in and its back. so that pretty much narrows it down to an abs issue but i am not getting the abs warning lamp on the IP so any body got any other diagnosis suggestions i might try to narrow it down?

 

[ptschram]

Did you jack it up to check the bearings???

 

[Hoot]

no not as yet. i am at work and the only pump i have is the bottle jack from the engine bay. if it is the bearing why would it not repeat the same shuttering with the abs fuse pulled as it does with the abs fuse in?

 

[singingcamel]

check the abs wheel sensor for abrasions cracks , clean the seat and sensor a reseat you may need a new abs sensor.
Hows the brake pads look.
follow PT's advice and check for play in the wheel bearing.

 

[ptschram]

I tore a '95 RRC apart last week where the upper swivel bearing had disintegrated and took out the ABS sensor, it was scary to drive.

 

[d1driver]

My bet is bearing as well. Any slop in the bearing will get multiplied when the abs does its thing on ice or snow.