ABS Dash Light On

ABS Dash Light On

ABS Dash Light On
Dieselpuller
20 October 2010
10:09 AM		 HELP!  I changed the front left steer axle seal and bearings on my 2001 Volvo VNL64T 660 and now the ABS light on the dash is on.  It was a real tight fit but went together OK.  Can anyone possibly tell me if I've missed something or have done something wrong or is it just a matter of a computer reset and if so how is it reset?  The brakes are working fine on a test drive.  Thanks a bunch for any help.
Greg
Louh
20 October 2010
11:12 AM		 I'm not a brake expert but here are some ideas that popped in my head.
The distance from the "pickup" to the "exciter ring" is too big?  I'm not familiar with Volvo but guessing it's like most other trucks.  The pickup needs to be really close.  Also, if the wheel bearing preload is not correct it will cause the gap to fluctuate and trip the light.  Sometimes when working on the truck the sensor can get knocked back into the spindle and cause the gap to be too great.  Most of the time it is just a push/press type of fit that keeps the sensor in position.  If it was hit accidentally it could also be cracked or broken.  The sensors get brittle after a while and can break easy.  You can check the sensor with an ohmmeter.  I don't have the values but a quick search and you can get them.

Basically, if it's open then no good.  There should be resistance.  Lets see, what else?  Exciter ring broken? or the teeth clogged full of metal or junk?  Pickup has metal shavings stuck to the magnetic end?

Just throwing out ideas. Maybe someone will have some better ones here soon.
MacDaddy
20 October 2010
08:04 PM		 I think Louh hit most of the points.

Try pushing the sensor by hand. it takes a bit of force, then 'goes'.  Do not under any circumstances use a hammer.  Also the ring could have been damaged when off of the axle, or if you used a hammer on the sensor it may have a divot in it.  You could read the fault codes off the cluster MID136 SIDxxx FMIxxx
David Couture
21 October 2010
06:22 AM		 How fast was your test drive?  AFAIK,  WABCO units need to be driven faster than 4 mph to reset the light.

Don't worry.  An ABS malfunction will never disable your brakes.  The literature says that ABS is only disabled on the affected sensor.  So, it's your job now to detect wheel lockup. :-)

These sensors give 0.2 volts AC @ 30 rpm and resistance is 900-2000 ohms.  Check out page 29
dc.
Dieselpuller
21 October 2010
09:57 AM		 The correct answer is" the distance between the sensor and the exciter ring" thanks LOUH.

There was a speedi-sleeve on the spindle and the seal that I was sold was not the proper one for the sleeve.  The new one is an upgrade which does not require a speedi-sleeve.  So the speedi-sleeve was not allowing the hub to go all the way on to the spindle.  All is well now and the dash light is off.  Thanks guys for the input.