What is the control box attached to the master cylinder for?

[BIG_KID]

Remove the black plastic box and the aluminum block with the lines that's bolted to the bracket what your left with is an empty hole in the bottom of the valve on the master cylinder and the single rear brake line sticking up from the bottom. screw them together and bleed the rear brakes. If done correctly I can promise you the best brake your truck has ever had and you will never see the abs light again except at start up. I'll get some pics tomorrow showing how it works but just rip all that **** out and have amazing brakes like you think your truck should. No more spongy brake pedal

I did this to mine and the brake pedal IS less spongy

 

[MouthForWar]

If you have spongy brakes it has nothing to do with the ABS controller. Delete it if it makes you feel better but it makes no difference. This comes up all the time on the forum, delete this, upgrade that, bigger whatever... Might as well light your money on fire doing that stuff. The brakes on these trucks work, if they don't feel right there is something physically wrong with them that needs to be fixed.

This. I've seen this time and again and other vehicle forums too, and I've watched it countless times throughout my career. People mask problems, fix them the easy but incorrect way, or do stuff that gives them a very anecdotal and subjective result while messing with stuff that was engineered a certain way for a certain reason.

I'm obviously all about mods and stuff to a certain point, and honestly you don't NEED ABS...but deleting your ABS controller to solve a spongy brake problem is not the best way to go about things, imho. If it fixes it, it's probably either a) correlative, not causative, or b) masking a real problem elsewhere that needs to be tracked down.

Just my 2 cents.

 

[honkon]

After looking very closely, it does have the extra bits. Attached is a pic of what it looks like on my 1990.

So .....how does the darn thing work? where does it get its data from?

If it is working properly would one ever feel a pulsing of the brake pedal when activated?

I've driven a couple 90s fords with rear abs and you can't hardly feel it at all in the brake pedal when it's activated. You can hear and feel the rear brakes applying and releasing in the body more so than the brake pedal.