Rear ABS / RAWL delete

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Rear ABS / RAWL delete

Postby opiebennett » Sun Mar 08, 2015 5:33 pm

Ever since I've owned my truck, the brakes haven't been all that awesome. They felt spongy, and generally sucked. After a while both the ABS and "Brake" lights would come on and stay on. I bled them, I changed the master cylinder, put all new hardware in the drums, even swapped the rear to disc's, and never could get them to perform like I thought they should, but eventually gave into the thought that they were 1991 dodge brakes, and that was that.

After loosing my VSS circuit on a road trip, having the odometer, speedometer, cruise control, and overdrive all stop working, I was attempting to diagnose that. In doing so, I jacked the rear of the truck up, and put it in drive to spin the rear driveshaft and verify that the speedo gear was turning. This worked well, until I went to stop the tires from turning. I hit the brakes, and the tires didn't even slow down. This identified to me that my rear brake circuit was completely not working.

Some research, and given my symptoms, ABS and "BRAKE" light on, non-fuctioning rear brakes, and I agreed with the internet commando's that my Rear Anti-Lock actuator (sometimes refereed to in internet land as the RAWL or Rear ABS module) needed to be replaced or bypassed.

Reading the forums, you HAVE to go to NAPA and get part numbers:
7917 and 7828

So, I went and got them. Something like $10 for the fittings, and an $8 quart size jug of brake fluid later and I was on my way.

Image

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The bin they are located in behind the counter refers to them as Master Cylinder adapters.

So I got home, and looked under the truck, and found the ABS module / RAWL on the drivers side frame rail, approximately above the rear axle.

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Some staring at the Napa fittings, and I determined that the internet was, infact, right.

The line headed into the back of the RAWL has the 5/16" brake line fitting on it. You could unbolt the brake line that runs from the master cylinder from the RAWL, and screw the 7917 fitting on to that, then the 7828 fitting onto the 7917 fitting, then bend the line back forward, and install it (with the adapters) into the top of the rubber brake line that goes to the axle.

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Bryan 'Opie' Bennett
91.5 5.9L with 21mm H1C/A518/NP205 Reg Cab LE Pyro/Boost/Trans Temp/BD Fuel Pin/Some fuel screw/Diamond Eye 4" exhaust/B+M Deep Trans Pan/3rd Gen aluminum wheels
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fuel screw!!!!
 
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Re: Rear ABS / RAWL delete

Postby opiebennett » Sun Mar 08, 2015 5:38 pm

If you did that, it would look something like this -
Image

I, of course, decided that it had to be more difficult than this. I decided that I didnt like all the extra fittings in there as possible leak points, and, based on an interenet diagnosis for my faulty brakes, without any verification testing, decided to just cut out the 5/16" fitting, cut the line shorter, re-flare it with a 3/16" fitting, and have a now shorter line that goes straight from the master cylinder to the rubber line that heads to the axle.

So, a "before" picture -
Image

I removed the line connecting the RAWL to the rubber hose, and cut one end off to get the 3/16" fitting that I'd need.
Image

Image

Then I removed the long line that fed the RAWL, cut it shorter with my roller cutter, and cut the protective spring off -
Image
Bryan 'Opie' Bennett
91.5 5.9L with 21mm H1C/A518/NP205 Reg Cab LE Pyro/Boost/Trans Temp/BD Fuel Pin/Some fuel screw/Diamond Eye 4" exhaust/B+M Deep Trans Pan/3rd Gen aluminum wheels
User avatar
opiebennett
fuel screw!!!!
 
Posts: 53
Joined: Mon May 20, 2013 7:39 pm
Location: Port Orchard, WA

Re: Rear ABS / RAWL delete

Postby opiebennett » Sun Mar 08, 2015 5:45 pm

After some "on the back with brake fluid dripping on you" flaring motion, I now had a flared end, with the same 3/16" fitting that used to go into the rubber line.
Image

I screwed that into the rubber line, and had a buddy come over to help bleed the brakes.

Hol-y-Cow.

I about put myself into the dashboard the first time I hit them. Scared the heck outta me.

Stops awesome now.

I unplugged and removed the ABS actuator from the frame rail, and took a photo of all the removed parts -
Image

And pulled the glove box down, and unplugged the ABS computer behind it. The grey plug in this picture -
Image

No more lights on the dash, a good stopping truck, and 2 spare weird brake fittings to throw in the "this might be useful someday" drawer.

Also, it should be noted that you could buy a 3/16" female x 3/16" female adapter, and throw that, combined with your two other Napa adapters together, and just connect the two lines that goesinta and goesoutta the RAWL together, if you were so inclined, and in that way, you'd be able to put it all back if you wanted, for some reason, or if you procured a working ABS actuator.
Bryan 'Opie' Bennett
91.5 5.9L with 21mm H1C/A518/NP205 Reg Cab LE Pyro/Boost/Trans Temp/BD Fuel Pin/Some fuel screw/Diamond Eye 4" exhaust/B+M Deep Trans Pan/3rd Gen aluminum wheels
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opiebennett
fuel screw!!!!
 
Posts: 53
Joined: Mon May 20, 2013 7:39 pm
Location: Port Orchard, WA
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Re: Rear ABS / RAWL delete

Postby ArtBee » Sun Apr 26, 2015 10:08 pm

Nice story!

I just started having rear brake problems today on my drive out to work (560 miles/900 kms one way). My brakes work normal one time, and then the next time the back of the truck shudders, pedal pulses (both violently). No ABS or Brake lamps turn on ... they both bulb test good. Figured it was the thing on the frame and I have to get it off there ... haven't tried unplugging anything either. Brakes have always been less than impressive even with all new parts. Will have to look and see if my lines will handle bending and a re-flair (they are kinda crusty) ... may have to remove the fuel tank and bend up a new one from the master backwards.

Anyway ... thanks for the interesting read and pictures!
Art
1993 W350, 1991 D250 (non IC), 1969 Plymouth GTX, 1961 Chrysler 300G, 1966 Chev BelAir
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fuel screw!!!!
 
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