K-H ABS Delete? Replacing Brake Line Questions

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Svetlana

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Brake system is a JB7. Truck is 2000 K2500. So after doing some poking around I've seen a lot of info for pre-94 trucks removing ABS since they have a different system. On the trucks with the K-H ABS module, if I remove the ABS system is there anyway to do it where the light won't come on? Also, as far as a proportioning valve goes, can I just get any adjustable one for the rears that would accept my line size, and a T for the front brakes? The aftermarket ones for the rear seem to be easier and cheaper to come by... I had my Front to rear brake line burst on me the other day. I'm waiting for lines to come in now and trying to get everything in order. I'll be replacing all the lines since it's only a matter of time for the others to go.

Lastly, how important is it to keep the 1/4" line running back to the rear T? I plan to but I'm noticing most of the proportioning valves say they accept 3/16" line. I suppose I could use an adapter, but I would prefer to keep things as clean as possible. Just trying to nail down the details, having some trouble finding some of this info. Thanks!
 

Gibson

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Why would you want to remove the only system that can lessen or prevent wheel lock-up?
The so-called "adjustable" proportioning valves do absolutely nothing to compensate for various amounts of weight in the bed.
Dirty little secret: The adjustable valves don't really "proportion" anything, they only can restrict the flow, they don't change the line pressure to the brakes.
They were designed for lightweight cars, in which the front-to-rear weight bias is pretty much constant, not heavy trucks.
 

Svetlana

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Well I'm not sold on the idea, since I would need to buy more parts anyway. In my experience the ABS hasn't been that consistent.
The rear axle weight variance is something I hadn't considered though. So does the ABS module actively adjust the line pressure applied to the rear to compensate for varying loads?

Side-note to you Dirty secret: changing flow always causes a change in pressure, which means it has the ability to regulate or "proportion" the line pressure for rear brakes to work well with the front brakes. So I'm not sure what you're getting at there unless you mean to say that a proportion valve system is static while ABS is active relating to rear line pressure? If that's the case I won't touch it, I guess that would be why it was hard to find a good write up of someone removing it similar to the old style one!
 
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Gibson

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Well I'm not sold on the idea, since I would need to buy more parts anyway. In my experience the ABS hasn't been that consistent.
The rear axle weight variance is something I hadn't considered though. So does the ABS module actively adjust the line pressure applied to the rear to compensate for varying loads?

Side-note to you Dirty secret: changing flow always causes a change in pressure, which means it has the ability to regulate or "proportion" the line pressure for rear brakes to work well with the front brakes. So I'm not sure what you're getting at there unless you mean to say that a proportion valve system is static while ABS is active relating to rear line pressure? If that's the case I won't touch it, I guess that would be why it was hard to find a good write up of someone removing it similar to the old style one!

OK, here's what goes-on.
The ABS "knows" if the wheels are turning or not, it IS an active system
When you hit the brakes the pressure from the MC is transmitted thru the system to the brakes and the wheels slow down their rotation, the ABS does nothing because the wheel is still turning.
If the wheel stops turning, (locks,) the ABS knows that, and it releases some fluid pressure to un-lock the wheel.
And, the ABS not only knows if the wheels are turning, it also knows if the drive shaft is turning, so when you're sitting at a stop light with your foot on the brake the ABS doesn't release the brakes on you.
Your comment about changing flow changes pressure is not true with a closed hydraulic brake system.
There is only a small amount of "flow" until the rear shoes expand out to grab the drums.
At that point their is NO flow, their is only a transfer of pressure thru the medium of brake fluid.
Besides the ABS, the only "pressure" control to the rear brakes is built into the Combination Valve, located near the MC, and one of its jobs is to limit the rear line pressure, but it has no way of dealing with a locked wheel.
The combo valve sets the upper limit, but cannot reduce pressure,, that's the job of the ABS.
 

El Tigre

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Many have deleted this ABS system. Most adjustable prop valves are 1/8NPT ports that accept 3/16,1/4,or AN fittings. They work well to prevent rear drum brakes from locking up. Also consider installing a residual pressure valve to rear brakes if drum.
 
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