I have an 01 dakota sport. Was driving and brake pedel became rock hard, then to the floor it went. I was 70 miles from home. Next morning, I jacked up the rear end and found bad wheel cylinder. I replaced both rear wheel cylinders. I am unable to get fluid to rear. I understand that this model has rear antilock brakes. I was told by a family mechanic that the proportional valve had been tripped. Worked with that for about eight hours. Bled the front brakes a hundred times trying to equalize the pressure so the valve would allow the rear to work. No LUCK. Replaced Master cylinder, bled fronts, tried rear NO LUCK. Was able to get Brake light to go off. Using Mighty Vac was able to force or suck fluid to rear. Still no rear brake pressure. Wont Bleed by pumping brakes, wont gravity bleed.

Any thought would be great.

 

Gravity might bleed the breaks although if there is no fluid then some thing might be stopping the fluid from getting there. There is some times away to adjust the valve. Have you checked the break lines all the way from the front to the back for a clasped line.

 

Are you sure you only have RWAL?

ABS was available as an option. If you have ABS you might need a scan tool to cycle the pumps/solenoids.

 

I've got rear-wheel only also ABS.
The mechanic is right. If it trips it's gota be re-set.
How?? I don't know. (Great help huh)?
Someone here will chime in with the answer.

 

Just thought I would update my post, I was able to fix it. The brake bias "pressure switch" is serviceable (manual says that it is not). Two bolts hold it on to the wheel well, four brake lines (one front input one front output, one rear input one front output), two "blue plungers". I removed it from truck, disassembled it (removed blue plungers) and cleaned everything with mineral spirits. I reassembled it, mounted it back to wheel well, hooked up the brake lines and topped off the master cylinder. Finally I opened up the rear brake bleeders and low and behold they gravity bled!!!
Thanks for the replies, Thanks for the manuals provided by the kick butt guys from this site. Hope this helps someone else.

***Disclaimer*** Brakes are important it is best to have them serviced by a pro.