anti-lock motor

[JIM S.]

My hood sticker sayes I have rear antilock... but every time I get on the brakes hard they lock. so I am wondering what might be the prob... it stops straight... . FINALY! but I am thinking the anti-lock motor is dead... . anyone have any experince with these? or any ideas what could be the prob... ??? Jim

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1995, 2500, 4x4, 3. 54, auto,130,000 miles, custom fuel plate, boost and EGT gauges, 215 HP injectors, RE-0880, custom 4" from down pipe.

 

[illflem]

Many folks would consider it a blessing. I like the anti locks on snow and ice, but that's about it.

 

[Missouri Mule]

Jim,
Are your back brakes locking up?
Are your front brakes locking up?

On rear anti-lock back breaks should keep rolling. But the front will lock up.
If your holding steering wheel sttaight and no other apparent problems(alignment,tires, brake pull) the truck should stop in straight line.
Usually back drum brakes are not adjusted exactly the same (there are ways of getting them close) so which ever rear brake locked up first that would be direction the truck would pull toward.
Since your stopping in straight line I would assume front brakes/tires are locking, rear brakes/tires are rolling.
A lot of times gear lube from leaking seal or brake fluid from leaking piston will cause back brakes to grab harder causing lock up.
If Rear Anti-lock is not working idiot lights on dash should be glowing.


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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

 

[JIM S.]

rears lock up ... . fronts seem to work fine... and I get no dash lights(abs) so I dont know... Jim

 

[Missouri Mule]

Jim,
As I recall back wheels have wheel speed sensor. If wheels seem to be going in skid mode this senor sends message to RWAL module which controls brake fluid pressure to back wheels, which in turn keeps back wheels from locking up(rolling).
I will have to re-read brake section for more details on system function.
But right now mis adjusted brakes or some type of fluid in drum would seem to be problem.
Have similar problem with rear right tire lately it is braking harder then left and tends to skid(lock up) on loose gravel or wet road. I figure my rear axle seal is starting to blow again. But than again I took my mom's car to same mechanic and her right rear wheel is doing the same thing. Her car is front wheel drive with ABS. So it could be brake adjusted to much.

[This message has been edited by Missouri Mule (edited 05-28-2001). ]

 

[Deezul1]

Jim
Do you get the orange antilock light with key on motor off at the 1st 10 secs of switch on? If not then the anti lock puter may be unplugged or the light burnt out or missing.

 

[JIM S.]

Yea I get the light at first start up just like normal. . and both rears brake evenly. . I had sevier issuses with the drum on the right so a couple of months ago I went ahead and replaced drums wheel cylenders and shoes!... the brakes work great exept the rears lock up when I need hard brakeing. so most of the times it ok... but wouldnt want anyone else to drive it the way it is not knowing how to use brakes. . so I really want to get it fixed, dont want my soon to be wife to have an accedent! Jim

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1995, 2500, 4x4, 3. 54, auto,130,000 miles, custom fuel plate, boost and EGT gauges, 215 HP injectors, RE-0880, custom 4" from down pipe.

 

[sam peterson]

there is no motor for the antilock brakes with the RABS system. pull the anti-lock relay and see if it still gives the problem. if it does it is not anti-lock related. ---Sam