Rabs Valve

[icanfixall]

I do not have any brake lights yellow or red lighted on the dash. As for a proportioning valve ... Nope. Do not have one. I do know I never bled the rabs valve when I installed it. Also I do not get the anti lock rear barke chatter one would expect from the locking and releasing action of the rabs valve. I believe we are supposed to make small skid marks like any big rig panic braking does. But not really sure. What I do know for a scarey fact is during a sudden panic braking I have instant brakes for maybe 1 second then it feels like next to nothing as I continue moveing forwards to near collisions when it happens. No dealers are going to tell me thats just the way its supposed to work. Actually no dealer has seen my rig in their drive but they do see me drive by waving at them..

 

[MTKirk]

I do not have any brake lights yellow or red lighted on the dash. As for a proportioning valve ... Nope. Do not have one. I do know I never bled the rabs valve when I installed it. Also I do not get the anti lock rear barke chatter one would expect from the locking and releasing action of the rabs valve. I believe we are supposed to make small skid marks like any big rig panic braking does. But not really sure. What I do know for a scarey fact is during a sudden panic braking I have instant brakes for maybe 1 second then it feels like next to nothing as I continue moveing forwards to near collisions when it happens. No dealers are going to tell me thats just the way its supposed to work. Actually no dealer has seen my rig in their drive but they do see me drive by waving at them..

I strongly suspect you have air in your rabs valve, I'd re-bleed the whole system thoroughly. I don't believe the early systems are supposed to "pulse" like modern systems, My pedal just slowly falls to about the bottom 1/3rd of pedal (at this point the fronts are locked).

 

[79jasper]

In that case, I would just bleed it and see what happens.

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[OLDBULL8]

Just in case you want to check this.

Does the RABS and Brake lights self check when the key is 1st turned on.?

 

[DaveBen]

The sensor is the magnet. The ring is not. Pull it out of the rear end and check is it is fouled with small metal bits. Replace the sensor if needed.

Dave

 

[ifrythings]

If your abs kicks in and the brake peddle sinks to the ground it's because the isolation valve is bad or not being turned on, what this causes is instead of blocking the master cylinder to the rear brakes then energizing the dump valve which goes into the the spring loaded accumulator releasing preasure on the rear brakes and preventing lockup, it ends up dumping the master too which as we all know what a bad rabs valve does to are brake peddle (soft/low/multiple pumps) does the same thing while you are braking.

The operation of the abs system is to lock out the Mc, relieve preasure on the rear brakes until they are back up to speed, then it allows the Mc back into the system to bring the preasure back up and if the rear brakes start to lock up again it repeats the cycle. This is why as the abs system is working you feel a pulsing brake peddle that slowly lowers during the event unit either you stop, run out of peddle travel or the accumulator gets full. (Newer abs systems can make there own preasure so the brake peddle gets "locked out" and it controls the the maximum braking power before skidding, while skidding gives you very little stopping power)

I have some pictures of this if anyone would like me to post them.

 

[icanfixall]

Well for a few days I have "needed the services of a foot on the brake peddle"... So one would think the good wife would lend a foot... Nope. What a worthless puddling of a woman from ******... Well she finally did TRY to help but I sure got a gut full of crap for it cause I was not there when she wanted to help. Did I tell you my life sucks.. Yea sure did. So the sun is going down and I need a flashlight under the truck to see if any air comes out. Did the bleeding 4 times. Never drained the reservoir down much but still not sure any air came out. Mostly clear fluid too. Not sure where else to go now but probably surely going to hell for my attitude. Temp today was 88 or 89 degrees. Really nice weed pulling weather too....

 

[79jasper]

Gary you should make a pedal pusher from a caulk gun.

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[laserjock]

Or get a vacuum bleeder. $25-35 at horrible freight v

 

[icanfixall]

I want a mighty vac brake bleeder system. Years ago I made a pressure bleeder from a cut down propane tank. Then I made a cover that fit the Bendix duel camber master cylinders. I could bleed the fronts or the rears easily or set the feed to go into both front and back at the same time. Tried using it on the Ford hydroboost reservoir but nope. Not working. So I need at least a screw on cap designed for pressure. Trying to make a master cylinder cap seal was not my strong suit.....

 

[fsmyth]

A quick search did not turn up anything, but back when I had a shop, I made one
from a piece of 1/4" plate, with 2 holes for a chain and wing-nut/screw. Drilled and
tapped 2 holes in the plate, one for the front and one for rear.
Just used a piece of an old inner-tube for a seal. Used it for years.

For the ones with the round caps, I had a stepped-thread adaptor from one of the
tool trucks. Plus and assortment of large rubber stoppers with the hole drilled in them.

An old junk regulator and shop air. Soldered two copper tubes on the cap that fit the
1-gal. brake fluid can - 1 at the top for the pressure, and one that dropped to the
bottom for the fluid.

All this was well before all these parts and tool stores

 

[Black dawg]

It seems odd to me that you can slide the rears at all. These things in stock form are proportioned soo weak to the rear it is not even funny. I wonder if the bigger master (and its internal proportioning) are messing with the rabs valve.

 

[79jasper]

I can slide mine.
No brake upgrades. Course I may slightly over tighten my rears now and then. The auto adjusters on mine broke, so they'll back off.

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[MTKirk]

Well FRACK! I've caught the RABS blues, light came on yesterday and stayed on. Worse; when I ground the diagnostic lead I don't get a flashing error code, just a continuously glowing light, So now I get to troubleshoot this entire system with no direction whatsoever from the self diagnostics. ARGH!

I guess this means my control module is likely shot.?...

 

[icanfixall]

Well FRACK! I've caught the RABS blues, light came on yesterday and stayed on. Worse; when I ground the diagnostic lead I don't get a flashing error code, just a continuously glowing light, So now I get to troubleshoot this entire system with no direction whatsoever from the self diagnostics. ARGH!

I guess this means my control module is likely shot.?...

Any chance your brake fluid is low in the reservoir ? that too wil bring on the dash light.