I've replaced the wheel cylinders and calipers on my FIL's '90 Ford Ranger with ABS.  I was able to bleed the front brakes finally.  I've so far not managed to get anything out of the rear, not even air.  I've read sporadic mention that some vehicles require a special tool in order to bleed them.  I'm sure hoping that's not the case here.  Does anyone know a trick that might work?  Apparently on non-abs Rangers, there is a valve that must be bled, but that doesn't seem to apply to this truck. 

Any ideas would be appreciated. 

FWIW, I tried sucking fluid through with a Mity-vac and also having a helper pump the brakes while I work the bleed screw. 

From my foggy memory....I don't recall anything special about the Ranger ABS ..... but it was only for the rear wheels is it not?

If you are getting no flow of any fluid or even air then I would suspect that you have moved crud in the master cylinder to either block the ports on the master or the various small ports and lines in the ABS unit. Bad and very bad.

I would venture to guess you are full stroking the brake pedal on a 22 year old master cylinder.....

In this order...... I would reverse bleed from the rear wheels, you will need some sort of injector like a Phoenix Injector that has some pressure behind it. Remove the line at the ABS unit as you do this....you may dislodge the crud in the ABS unit. Got flow? No ? Replace the ABS unit and the master. Yes? replace the master.

I would suggest ever so gently that you may want to call a competent mechanic and then a tow truck. Bleeding ABS units and Master cylinders is a plus 8 on the skill chart. 

 

I just had my 91 rangers brake sys completely replaced. just like you i went into this changing wheel cylinders. If you have not changed your fluid in a while you may have a blockage in the line or there is a juntion block between the master cylinder and the rear brakes. crud will get into this block and no fluid will make its way past it. in the end i ended up changing out rotors, pads, drums, shoes, calipers, wheel cylinders and all the front brake lines. course you hit the brakes now and it will put your happy ass through the windshield. so in the end it was worth the trouble. hopes this helps

At the moment I'm thinking it's the RABS unit.  The fronts work well enough.  I have a section of gravel drive and I tested them out there.  I would get up a bit of speed and jam on the brakes.  Of course, the fronts work fine.  What I found was that the rears would apparently get a little more pressure each time I jammed on the brakes, but the pressure wouldn't release.  After a few times of this, I could bleed off the pressure which of course is very little fluid, then the rears would release and I could go again. 

Reading up, it looks like early ford RABS units were not very good.  Apparently a lot of people bypass them.  I may do that eventually.  My only problem with that is that there appears to be no other proportioning valve.  I think I'll verify by checking for pressure upstream and downstream of that unit.  Then I'll take it off and see if I can clean it.  If worse comes to worse, I'll just bypass it.  The only problem is that the ABS light will be on from then on.  I suppose that's not terrible on a 22 year old truck.  It is my father-in-law's truck so I'd rather not do that, but we'll see.

Thanks for the tips.