[coldair]

I have AP racing 6 piston big brakes up front and EBC big brakes in the rear. the truck only has 88,000 miles on it. I have changed the master cylinder, brake fluid,

sensors and

hoses at the wheels are all new stainless braid. I have taken it to two shops and nothing they can find. no brake failure lights and nothing shows up on a diagnostic tests.
but I can't remember when was the last time I felt the brakes pulsate like they used to even driving off road or on slipper roads it acts like the old style brakes.

where can I find an ABS module that will work? is it the pump or the module? is there a check valve?

 

[Maryland dieselnick]

Is it a pulse or an ABS jackhammer feel? An ABS feel is distinctly different from something down stream.
Try pulling up the two front and rear abs sensor in live data. See what each reads standing still and what each are doing going down the road.
Second step is to use a dial indicator on the rotor to see how much runout you have. Do the inside surface as well as outside.
Next pull the caliper at the axle flange and check to see if it slides on the pins.
Next is check the calipers one at a time and use a piston retracting tool to feel the resistance pushing the pistons in. If you get high resistance that does not fe normal, crack the new braided line loose where it meets the steel line.

 

[coldair]

thanks for the response. I believe it is just a 3 channel system as I only have one brake line running to the rear with a single speed sensor on the rear dana 80. I had the same issue with the stock rear which leads me to think something is wrong with the abs system

 

[Maryland dieselnick]

Yes, you are correct as to the system.
I think if you try to determine the feel by how I described it ( get up to speed and jam on the pedal. Abs should kick in. The pedal will drop a little and than rapidly jackhammer under your foot), will help you separate ABS issue from other components along with monitoring the the sensors standing still and going down the road. Follow all that I wrote and you will solve it.

 

[narmalee]

I have nothing to add about the ABS since i routinely delete it from my vehicles

I just wanted to say how awesome that grocery getter looks!

 

[Maryland dieselnick]

That is one very nice looking truck. Better slow your roll so you don’t roll.
How do you get into it?
Can you take a photo of your heater hoses from heater box to engine points and to where they meet the lines running to the rear heater so it’s clear so a diagram could be made up?