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91 Ranger RABS valve and ABS Light - Resolved

AlphaTX

Member
Joined
September 17, 2013
Messages
33
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City, State
Dallas, TX
Year, Model & Trim Level
91 Ford Ranger XLT
So Here's the deal. My father In-Law brought over his 91 Ford Ranger 3.0 XLT for a simple idle issue.
While looking in to it, I found a host of issues that I have resolved with the help of these forums and the interwebs.
However, many posts I reviewed did not often end with resolutions or feed back of a solution.
This is one of several posts I'm making to log my problems and fixes on this truck in hopes to return the help I've received.

Issue 1:
This one had a few things that I went through... It all started with the "Rear AntiLock" light being on...
Forum threads led me to believe that it was the ASS (ABS speed sensor) mounted on the top of the rear differential.. A cheap replacement from Orielly's (~$25), but that didn't fix the problem.

Other threads mentioned pressure, but the Master Cylinder Reservoir looked alright... But, I topped it off anyway and bingo bango, the light went out. Seems that for some reason the fluid level sensor was all that was needed to trip the RABS light, though I would have expected the Brake light to be tripped instead... Oh well, easy fix right. Maybe the internal float was stuck.....

Issue 2:
So once I was done with everything, I went to tool down the road when low and behold, I had no brakes at the end of the street (mind you, I had driven it a few times without issue by this point). Some pumps of the pedal and pucker of the sphincter and I stopped.. First thought was Master Cylinder or air in lines.
Going the cheap route, lets bleed... Besides the fluid being as dark as motor oil, I really got confused when nothing came out of the back bleeder nipples. Some more research informed me that the RABS valve (which is located on the inside of the frame just below the MC in the front) has a tendency to corrode internally and fail closed. Thus cutting off pressure to the rear brakes and being a cause for spongy pedal, behaving like a shot MC. I know... it doesn't make sense to me either, but before you Flame me stating how a spongy pedal is not the RABS failing... do some searching.. Too many people (including me) have had it fail with these very symptoms, only to replace the valve LAST (meaning MC and booster first). Just to find out that the problem wasn't fixed until the RABS valve was replaced or bypassed.

A lot of solutions I found was just to bypass the thing by coupling the lines and removing the RABS altogether.. Not to mention, many owners expressed an opinion of the RABS being a rather useless feature. Since my wife and daughter will be learning stick on this ride, and it's my Pa's; I figured lets keep all safety features in proper order.. useful or not...
Orielly's and AutoZone are able to order the part from Cardone (#12-2029) for $120 after core return.

Here's where this gets interesting! I figure I'll remove the old and replace, easy peasy right?
Well, the line coming from the valve heading to the rear came off without an issue, and little more than a few trickles of fluid. The line coming from the MC to the valve was a whole different story. This was the first obstacle that vice grips couldn't tackle.. I doubt not that this thing corroded so bad internally, the line nut was now one with the RABS.

No biggy... We'll just rip it off and replace this line right? Wrong.
To speed this up, I had to make my own brake line. Here's why...
The line itself is 3/16 steel.
The connection to the RABS valve is 3/8 inch-24 (with a double flare end in the line).
The connection to the MC is METRIC!!! M12 1.0 to be precise. And being metric, means it has a Bubble flare at that end! Good luck finding this line anywhere, or the Bubble Flare tool for rent!

So, in the end:
I cut one tip of some stock 3/16 line from Orielly's (about a 3 ft piece)
Removed the provided fittings
installed (slid on) the 3/8 - 24 fitting for 3/16 purchased from Autozone (BLF-11C-5 AGC), for the existing double flare end (the one I didn't cut off)
Removed the Spring Sleeve from the factory line I removed and slid it on to the 3/16 line (perfect fit).
Added the M12 1.0 fitting for 3/16 (also from AZ, BLF-48C-5 AGS) and created my bubble flare using a cheap kit from Amazon that was about $28 and can do single, double AND bubble flares.
Reinstalled the line, bending slowly and carefully from the MC down to the RABS Valve. With the spring sleeve this made careful bending by hand possible without kinking.
Filled the system with fresh fluid (I properly dumped the old stuff), bled the lines and viola, I can stop again!

Note, since you'd be flaring, you could skip purchasing the pre-fabbed tube and just get bulk stock and your brake fittings.. I didn't learn this lesson until after I figured out that one fitting is SAE and the other was Metric.
Also, many people recommend NOT cheapening out on flaring tools. So, my 28 dollar kit did me just fine, but I won't be doing many flares so I'm happy. Just be 110% sure that your pipe is perpendicular to your flare adapter, and at proper length.. Cheap tools increase the "DOH!" factor.
 






I wanted to post a quick update...

After all of the above work, the brakes were fine, but that dang Rear Antilock light stayed on..

Shorting the code wire to ground didn't give me any codes. I found that if I kept my foot on the brake, the light stayed off until I took my foot off of the brake.
I re-bled the system thinking it was pressure related, but some troubleshooting later; and I found that it had nothing to do with "pressure" on the pedal, so long as the brake switch was activated. I removed the switch and place a jumper on it so that the brake lights were on, but no pedal pressure. Sure enough, the light stayed off. I had just replaced the Master Cylinder and reservoir with a brand new unit (not refurbed) during the above work, so my fluid level sensor was the last thing on my mind, but all roads lead to this direction.. So I found some online posts about testing the fluid level sensor and I went outside with my handy multi meter to start probing...

While looking at the connection, I saw three lines through the opaque plastic and thought "no... it can't be that simple".. I pulled the plug and felt in there with my pinky... Sure enough, the three prongs that were supposed to go INSIDE the plug, were smooshed against the top of the housing between the plastic and the plug!

I grabbed a dental pick and gently pried the prongs closer to the center of the opening. I plugged the connection back in, ensuring that things were lined up and I wasn't crushing the prongs now vs inserting them like they should be.

Turned the key, ABS light on, then off and stayed off (like it should).
Fired up the engine.... no ABS light..
Took my foot off of the brake pedal, and still no light. YEAH!!!

The brakes are all good now.
 






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