ABS light still on after replacing ABS Valve 1999 Great Dane Trailer

HI, I have a 1999 Great Dane Trailer. I replaced the Wabco 4 ABS valve.
The ABS light still stays on. I have not driven it yet because I still have to replace a wheel cylinder. I have a few questions I hope someone can answer.

1. When the air builds up I hear a whistling in the back of the trailer. When the air dryer kicks off it stops whistling. Is this normal? All four sensors do make the clicking noise.

2. On the ABS sensors, what should the OHMS reading be when checking them?

3. Is it better to use oil or grease for the wheel cylinder?

Any help will be appreciated.
Thank you.

 

Thanks for the fast response GrapeApe.
Yes it is the Hub and bearings. As soon as I replace it I will drive the truck and see if the ABS light goes off. I sprayed everything under the trailer with soapy water and I did not find a leak.

Thank you

 

That's exactly what it's doing. Thanks I appreciate all of your help.