My sig truck has a problem. There is a light on my dash that says REAR ANTILOCK that is constantly on. What is this and is there something I need to repair or turn on/off.? I worry when my dash has things lighting up orange and don't want to screw up my truck!

 

Your truck like two of mine have RABS(Rear Anti Lock Breaking System). Neither of mine work, and few trucks have working systems. It's not much of a problem, you just don't have anti lock but you still have full brakes.

Can't tell ya much about how to fix it, I've never tried to fix mine. But it seems to me most of the time it's the rear speed sensor.

 

the rabs in these trucks was marginal at best when it worked.
mine was bypassed back in 1988 because it would never work rite.

 

Rear abs can be a lifesaver. It prevents the *** of the truck from going all over the place if you ever end up sliding. The light can come on from something as silly as low brake fluid. Will abs issues throw codes?

 

I don't know if they have bigger brakes than when they had no anti-lock. They have to be controllable when the bed is empty but strong enough to stop when loaded to the max. Mine went out once and came back by its self. If it was the speed sensor, would it not mess with the tranny too?

 

I loved the rear ABS on my '95 F-150. No matter what load I had in the bed the rear brakes worked right. Rear ABS gives you all the braking you can get with a heavy load, but not too much with no load. That truck's predecessor ('85 F-250) would lock the rear brakes under moderate braking with no load and the brakes seemed weaker than necessary under hard braking with a heavy load.

But sorry, I've never worked on me ABS so I can't help you with the warning light.

 

I agree it can be a great thing to have when working right. Though I had an explorer back in the day that once ABS would activated at a slow speed when trying to stop normally and I almost wrecked. I pulled the ABS fuse after that, ABS has it's risks.

IIRC and it's been a long time since I looked into it. But I think there is a way to get the RABS to throw codes much like the old EEC-IV where you jump a plug and the light flashes.

IDK about Ford specifically but back in the day some trucks had load sensing brakes. It was a proportioning valve that connected to the suspension so when the suspension was high and unloaded the rear brakes were lighter. I like that a lot better but it's hard to get one of those valves and make it work right.

And no, if it was the speed sensor it would not mess with the tranny. The OPs truck very likely has a C6 which has no electronics. And if it's a E4OD it has it's own speed sensor in the tailhousing.

Wouldn't a 95 F150 have 4 wheel ABS?

 

Anybody know what is necessary to fix this? I would like to have it working and it would help if I decide to sell it.

 

How does the brake pedal feel? Soft, squishy, hard, fairly firm? Can you feel/tell if the RABS works when you stop hard? A lot of times the RABS will will quit working properly and cause a bad pedal feel and it'll be soft/squishy. The RABS isn't that great in these trucks. A lot of people take the spring out of the RABS module so that it just acts as a hub to pass brake fluid through and go without the ABS. Not a terrible option. My Rear Antilock light on my 88 F-350 goes on and off periodically, and I'm not sure of the reason. If you don't care about the RABS, or if it seems to be okay then I wouldn't worry about the light. Not sure about your state, but you can usually pass inspection with any amber brake lights on in the dash. You won't pass if the red brake light in the dash is on.


If you want to fix it...
First maybe try bleeding the RABS unit. It's on the inside of the frame near the front of the drivers door. If I remember right the bleeder is on top. This will help get rid of air/debris.

Look into the rear speed sensor. I don't have much knowledge about it, but someone around here on the forum probably does.

Check wire connections for corrosion and make sure they're tight. Maybe clean them and use some dielectric grease to keep them from corroding.

Since you got the truck recently, it's probably not a bad idea to bleed/flush the entire brake system. May help the issue if there's air/debris in it.

Hope you don't decide you need a new RABS unit. They run around $185 with a $30 core. I would take the spring out of the unit before I would replace it.

 

I don't know when 4 wheel ABS came into the F-series, but my '95 F-150 certainly had rear only. There were a few different winter situations where the front would lock up and the rear wouldn't. It wasn't that hard to deal with, but it was odd enough that it made it very obvious that it was rear wheel only.

 

I believe up until some time around 96 rear ABS was all that Ford offered. It may not have been ideal, but it was better than no anti lock.

 

that is really a matter of opinion.
the only one of my 13 vehicles that has working ABS is the 99 crown vic. and the brakes on that stink.
but i was taught to drive before ABS was ever thought of, so i know how to drive without a computer thinking for me.

 

Yeah, it isn't always better. I've been in vehicles with 4 wheel antilock and felt like the antilock made stopping distance longer. I'm used to going without antilock and have no issues stopping.

One time when I really don't like antilock brakes is on dirt roads. Down a steep dirt road hill antilock will pulse and still slide the whole time which make stopping worse than without antilock where you have more manual control.

 

anti lock on wet or mud is extremely dangerous too.
i have seen new trucks wreck because the ABS would not apply the brakes and the slid off into the woods where my old "junks" stopped with no problem even though they weigh a lot more.

 

according to my Ford book the light comes on when one side is getting less pressure than the other.I.E. leaking wheel cylinder or uneven brake wear.The solution is to fix the issue then to have an assistant pump pedal as if you were bleeding the brakes but you crack the lines as the pedal depresses if you have the right line cracked the light should go out. At the exact moment the light goes out you need to tighten the line and stop depressing the pedal.There is a needle inside the valve that needs to be centered this is what activates the light.