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The front abs brakes make a moaning sound,off and on, when the van is turning to either the right or left at times as well as when driving straight.When this sound is heard the ABS light is off on the dash panel. When the brake is applied the moaning sound gets louder and the pedal pulses and the van does not slow down as quick as it does when the ABS light is on.When the abs light comes on,It's on and off most of the time,braking to a stop is excellent.I took the van to a brake shop and they checked it with their testing equip and the read out was that the right front hub unit was defective. They installed a new hub abs/unit which they said would correct the problem.It did not solve it.It actually is worse now than before.Cost me 500.00 parts and labour for a poor fix. Contacted them and they are not sure what the problem is.I do not want to spend more cash on the van brakes if it can't be solved. What I would like to know is,can the abs brake electronics be bypassed so the conventional braking can be used.Is there a fuse or something  that can be removed to get away from the moaning sound and poor braking.Has some of you people out there had this problem and fixed it.Thanks for any help  

there are several good articles on ABS brakes on this professional mechanics magazine site...

start with these articles..

http://www.brakeandfrontend.com/Article/46336/diagnosing_wheel_speed_sensors.aspx


http://www.brakeandfrontend.com/Article/38809/replacing_hubs_with_wheel_speed_sensors.aspx


you will probably need a scan tool to read the abs codes and data stream...


there are so many things.. with computerized systems that just need to be done with a scan tool and knowledge of the system...

most techs actually take a car for a careful test ride with a tech 2 scan tool installed.. displaying the wheel sensor speed data as a graph...     accelerating and stopping while the mechanic passenger views the data stream..

if one wheel seems to stop.. the antilocks will unlock that wheel...  but once in a great while..  there are spikes in the wheel sensor voltage output.. of just one wheel.. with that.. the system thinks that wheel is going faster.. and it unlocks the other brakes..  letting you slide along in a panic..

as for bypassing the system...  i don't know if thats possible.. i have never tried it.. there are a lot of lines going and stuff in the valve block...  

Thanks Waynep722 for your reply.Will do some more research on this problem with the abs brakes.The moaning sound is getting more constant and pulsing brake action comes on even on dry pavement applying the brakes very easily. If any one else on this site has had this same experience, please feel free to speak up. Thanks guys.