Need lesson on RWAL

Bex · 10-29-2009, 03:22 PM

How do you check if RWAL is working or even on the car. My mechanic says he has never seen any wires to rear brakes that would indicate any electronic control. I looked in FSM and see that there is a rear wheel speed sensor on the rear differential. Is this the only outward indication by the rear brakes that there is RWAL? How can you tell if the RWAL is really hooked up and actually working. Thanks.

aquanaut20 · 10-29-2009, 03:54 PM

Quote:

Originally Posted by Bex

How do you check if RWAL is working or even on the car. My mechanic says he has never seen any wires to rear brakes that would indicate any electronic control. I looked in FSM and see that there is a rear wheel speed sensor on the rear differential. Is this the only outward indication by the rear brakes that there is RWAL? How can you tell if the RWAL is really hooked up and actually working. Thanks.

If indeed you have a wire loom on the rear pumpkin it will be the "HALL Sensor" for the RWAL. The other part should be a distribution block somewhere under the hood in series with the brake line feeding the back brakes. When the hall sensor senses rotational difference it triggers the anti-lock device and releases/reapplies pressure on the rear brake system. Some RWAL utilize signals from the Speed Sensor in conjunction with the rear Hall sensors.

If the system is working, the rear wheels will pulse brake on/off with the pedal under pressure and road traction is broken.

Caveat: there are many types of systems, all utilizing different methods of anti-lock, I do not know specifically what you may have.

HotTommy · 10-29-2009, 09:31 PM

This is just a wild guess, but on every car I've had with anti-lock brakes, there was a warning light on the dash that illuminated briefly each time the key was turned on. Do you have such a light?

kick-fix · 10-29-2009, 11:12 PM

the hand brake light stays on , if RWAL fails.

my blicking lights page shows this ,
click brakes ,

no actual end of axle sensors , only a hall sensor on pumkin like aqua says.
2 wires that is it. ground and sig.

the dump valve is siting right next to Master cylinder.

brake light is glowing.
brake lamp stuck on or flashing

even have schematic of it.

how to test it.?

1: is lamp out? test1
2: can you drive on grass and not skid rear wheels.
when the hall sensors , stops pulsing ( dead axle) the RWAL controller then dumps the pressure to the rear brake lines , letting pressure only happen to front.
crude has heck. ( this is like B&W TV, real crude technology) but heck we had to start somewhere ,huh?

have fun.

Salud

keithert · 10-29-2009, 11:30 PM

Would a 91 even have anti-lock? I know my 90 didn't.

kick-fix · 10-30-2009, 12:58 PM

89/90 is a generation
91 is another.

those photos i posted are out of the 91 FSM, and i spend way too much time mixing mine.

price a dump valve.

its rear wheel anti-lock brakes, just the rears and not each wheel just the ring gear has the tone wheel. need a pic , have it.

Bex · 10-30-2009, 02:13 PM

My brake light does not stay on. The FSM says there is a way to get codes out of the ECBM. Have you ever done this? As easy to do as getting codes from ECU? I assume that I have all the bits for the RWAL, (although I must admit I do not know what a pumpkin is....is that the big round center bit on the rear differential? My car originally was a rollover that this kid started to fix up again. I don't know if the RWAL was ever disconnected/reconnected, etc., and never have felt this pumping action when I use the brakes. When you say testing on grass, do you mean driving on grass and throw on the brakes to see if you skid? My mechanic (who has been working on this car for 12 years) was really surprised to hear I had RWAL, as he said he never saw any indication of it.

kick-fix · 10-31-2009, 02:27 AM

dear Jane.

yes, grass will make it dump if working and yes you will feel it. driving slowly on grass.
5mph or about. nothing dangerous.

the dump valve is right below the Master cylinder.
look for the RWAL controller just above and forward of right toe.
black 6 x 6" plastic box with connector , it must not be unconnected.
the RWAL has a jumper , read my page on it, it shows that BLANK no flashing = happy.

no code 12 , it shows nothing for happy, which is same for disconnected. sadly.
tell mech to look at part #32 , that is the dump valve.

and here, (links on my page)
http://www.kick-fix.com/brakes/rwal-controller.jpg

the jumper rules are there too, seem em.?

kick-fix · 10-31-2009, 02:32 AM

one PM is to pull the Hall from the pumpkin, (yes left side front 3rd member)
and clean the metal dust off the hall busness end.

common as nails to get dirty and dumb.
cause sensor so fail,

one way to test the braines is to cause a failure.
pull the dump valve connector, the RWAL must throw codes in set the Brake lamp on.
its a shared lamp.
do testing on safe street,no ice.

you will get dump valve open fails.
code 3 , flashing.

there is a whole section on RWal IN THE fsm.

Salud

Bex · 10-31-2009, 06:53 AM

Ok, well, found the dump valve. That was easy enough. Also found a 6x6 black box behind and above clutch pedal. In front of which are tons of wires. Who makes these things, anyway. You need to be a pretzel just to see the box, much less find the connector. Going on to your pages now, will compare with car, and then will probably need a chiropractor, as will probably be in great pain from these acrobatics. Definitely not for old people.