90 F150 no rear brakes/lock-up as well
02-02-2010, 10:18 AM
#1
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90 F150 no rear brakes/lock-up as well
Have a 1990 2wd F-150. ABS light as been on and off for a little bit now. I did all new front brakes- pads/rotors/calipers/hoses and rear shoes looked great. After about a week i had the RABS light come on and the rear brakes felt like they were dragging. After a bit that seemed to go away and fronts only will work- ie front brakes locked up and slid on ice while rear wheels rolled freely.
Put it up on a lift and rear brakes wouldnt stop rear wheels from moving. After messing with it for a bit that rear brakes eventually locked up. the Brake light stays on and the ABS light stays on. The brakes would not realease until i cracked the bleeder on the ABS pump. After that the wheels were free and went back to plain not working again.
Im thinking the RABS unit is clogged. The brake fluid was typical 200K miles truck dirty, maybe when the new fluid was added when bleeding the fronts it loosened up some crap and clogged the abs unit not allowing fluid flow to the rear and not allowing pressure to release when the pump kicks on.
Think this sounds about right? The rear brake bleeders are frozen so i cant bleed through them till i replace the wheel cylinders. I may tryi doing this first to see if i can flush new clean fluid all the way through
Put it up on a lift and rear brakes wouldnt stop rear wheels from moving. After messing with it for a bit that rear brakes eventually locked up. the Brake light stays on and the ABS light stays on. The brakes would not realease until i cracked the bleeder on the ABS pump. After that the wheels were free and went back to plain not working again.
Im thinking the RABS unit is clogged. The brake fluid was typical 200K miles truck dirty, maybe when the new fluid was added when bleeding the fronts it loosened up some crap and clogged the abs unit not allowing fluid flow to the rear and not allowing pressure to release when the pump kicks on.
Think this sounds about right? The rear brake bleeders are frozen so i cant bleed through them till i replace the wheel cylinders. I may tryi doing this first to see if i can flush new clean fluid all the way through
02-02-2010, 10:58 AM
#2
you have air in the pump. do a full flush & figure out on that truck if you need the computer & power bleeder to finish.
not sure on the '90 for the computer, but the last time i tried to mess with ABS is wasn't gonna be pleasant b/c I needed a computer that could initiate an auto bleed sequence & a power bleeder that could force the air out.
not sure on the '90 for the computer, but the last time i tried to mess with ABS is wasn't gonna be pleasant b/c I needed a computer that could initiate an auto bleed sequence & a power bleeder that could force the air out.