So i know how to bleed brakes but i know this truck has rear abs, is there any special procedure i need to do ?

 

In order, rt rear, lt rear, rabs valve below master cyl. That should do it.

 

This may seem like a simple question, but how you you know if your truck has rear ABS or not?

 

All trucks in this vintage have rear ABS. It's standard equipment.

 

Kewl.

I have sooooo much to learn. But I certainly appreciate the patience of the folks here.

 

On my '96, the RABS module is mounted on the inside of the frame rail, just aft of where the steering box bolts on to the frame rail.

Or, follow your brake line from the master cylinder down...

 

yeah im mainly wanting to know when do i bleed out the abs valve thingy or do i just bleed it out like normal. And u can find out if any of you cars or trucks have abs is they have wheel speed sensors, just just try to find the outline of the light on the dash

 

There's no wheel sensors on a RABS truck.
There is a magnetic pickup on top of the diff and a "tone ring" on the carrier.

 

The rabs valve bleeds just like a wheel cyl, has bleeder screw toward the front of the valve

 

yeah and thats a wheel speed senor is same thing, just a magnet that reading the tone ring and sends the frequency to the pcm. And on the brake bleed i just did it the old fashion way with no problem

 

Is it???

And what other wheel is it comparing speed too?

What about DSII trucks like mine that have an analog speedo and NO powertrain control module?

 

well there could be a speed sensor on your cable, id have to look at your set up, but on the older trucks that speed sensor on the back just tells your metering valve hey back off pressure to the rear im locking up, then on ones like mine that have a abs unit that pulses just the rear.. hard to say id have to know what set up u have

 

I've had occasion to replace my speedo cable and it seems all mechanical.
As does the speedo itself.

I understand that that the VSS must be comparing pulses to something, or the RABS light would come on every time I touched the brakes while stopped.

1987 was an odd transition year for non-catalyst trucks over 8,500 lbs.
No computerized powertrain management and no variable proportioning valve attached to the rear suspension.

 

If your truck has RABS the signal from the rear axle sensor goes to the RABS control module only. Since your truck is DSII there is no need for a VSS signal for the PCM. If you have cruise control then you would have a speedometer cable or transfer case mounted VSS.

 

Yeah,
Well I have a mechanical cable on my 1356, no cruise, no PCM.
So what is the RABS comparing the pumpkin sensor to?