Ok let me start with all brakes are good wheel cylinders on rear new. I did have ABS and brake lights on put a new to me module on the ABS system lights go off now. Now brake peddle when applied feels good then gets hard and the rear feels like it wants to lock up. I can let off and apply brakes again they seem fine Speedo working right from zero. I can unplug the module the plug that goes to the brake line block for the lack of a better term. Brakes work just fine please help thanks

 

2 or 4 wheel abs?

 

Rear ABS

 

Rear abs sucks. Pretty much useless.

have any vacuum leaks at/near the booster?

 

Not that I can find I did the booster test seem to pass. Something is wrong somewhere
If I unplug the bottom plug on the module it works fine it don't do it every time I apply the brake

 

Wonder if your rear sensor is being wonky...... but, your speedo works fine?

 

Yeah that was never a problem it first started I was running down the road bout 75 mph and the lights came on ABS and brake I changed the rear sensor didn't change it put the old one back in still acting up I unplugged the wire going to the aluminum block where all the lines run in and out works great then I plug it in and it goes to crap but the two lights stay on. I can't stand a light on

 

Wonder if you still have a bit o' air in there.

 

Ok if that was so why would it work just fine when the ABS is unplugged

 

ABS may be engaging when it is actually plugged in.

But, I know the RWAL on my truck is pretty much useless. It really just doesn't work worth a damn.