G2 Rear Disk Brake Conversion Dana 44

Stepping on the brakes while in Reverse backing down a hill unweights the front of the Jeep and tires which makes it a lot easier for the front brakes to lock up, not to mention the proportioning valve is set to give 75-80% of the braking force to the front brakes since in normal forward motion stopping, they're the ones that provide the primary stopping force. That's because when driving forward and you hit the brakes it unweights the rear tires (rear brakes too) so more braking power in the rear would cause them to lock up too easily which will cause skids/slides if not worse.

As suggested above, converting the rear drums to disks isn't going to improve your braking. The rear drum brakes are barely being used since the proportioning valve only gives them 20-25% or so of the total braking force so they're not even being used up to their full potential. Replacing them with disk brakes wouldn't gain you anything except easier maintenance.
 
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Can't argue with that eh? Thanks! I still got the conversion at a killer price & still plan on using it. I'm tired of sounding like the Nazi tank on Raiders of the Lost Ark & I will post a flow up. For now, I vote that everybody try this maneuver just make sure that I'm not insane.
 
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Can't argue with that eh? Thanks! I still got the conversion at a killer price & still plan on using it. I'm tired of sounding like the Nazi tank on Raiders of the Lost Ark & I will post a flow up. For now, I vote that everybody try this maneuver just make sure that I'm not insane.
Try that maneuver? I converted my previous 97 TJ from drum to disk brakes and learned first-hand just how disappointing it was.
 
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Ya, as you press hard on the brakes the proportioning valve pretty much shuts off the rear brakes. If you are pushing hard on the pedal and the fronts don't lock something isn't right. Bigger brakes is true but really only for the fronts. I'm not trying to rain on the rear disc parade but it would really suck if you spend all the time and money and didn't fix the problem.
That is not how the proportioning section of the TJ combo valve works at all. The rear pressure is always a proportionate percentage of the front pressure until the pressure rises far enough to kick over at the knee point and then it rises at a lesser proportionate rate but it is still rising as the front goes up in pressure.

The front has zero proportioning. It is straight pressure out of the master into the combo valve block fittings which are nothing but a common connection point or T. The 3 fittings at the back of the block are connected to one another.

The rest of what you said is spot on.
 
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My brakes function normal except in a situation where I am reversing downhill with my automatic in gear. There is very little stopping power. I can't even come to a complete stop. If do the same thing in neutral, it stops without hesitation. I used to have this downhill driveway, but have since moved. My Jeep is almost done with an engine rebuild & I haven't driven it in a while. I do recall the front brakes locking up on this busted driveway while the rears would spin in that particular situation. My concern is that I have a vehicle is that out of control when reversing downhill unless I pop it out of gear. While I am cognitive of that, I don't want it to be a risk if I'm out on a 3 or 5 point switchback. If that seems like a portioning valve issue, I'll follow that lead & yes this is an issue that nobody else has run across. All of us would rather have disk brakes over drums & I couldn't pass this conversion up regardless. I flushed most of the brake fluid when I put SS extended lines a little over a year ago.
The easier much more simple solution is to reach down and pop it into 4 hi before you move the rig. I have a steep gravel driveway and the fronts will lock, skid, rig keeps going. Pop it into 4 hi, lock all the tires together so the fronts will do the work the backs can't do, and go have fun.
 
So if my front brakes lock up & the vehicle is still in motion draggin the tires backwards downhill, it's normal? This only happens when my automatic is in gear. Out of gear it stops on a dime. It seems like the drivetrain is overpowering the rear brakes.
Your front brakes are shit.
 
So if my front brakes lock up & the vehicle is still in motion draggin the tires backwards downhill, it's normal? This only happens when my automatic is in gear. Out of gear it stops on a dime. It seems like the drivetrain is overpowering the rear brakes.
Which is it? Fronts lock and the rear tires are still turning?
 
The easier much more simple solution is to reach down and pop it into 4 hi before you move the rig. I have a steep gravel driveway and the fronts will lock, skid, rig keeps going. Pop it into 4 hi, lock all the tires together so the fronts will do the work the backs can't do, and go have fun.
I'll keep coasting backwards in neutral knowing that my brakes work fine in neutral
 
For those that wish to actually learn something.- The main reason that drum brakes work poorly going backward is they are a servo brake design that is self applying with heavy shoe retraction springs on the primary and secondary shoes. Primary and secondary are important since they are not the same size. In reverse the secondary shoe doesn't provide the same self apply forces that they have going forward. Add that to the bias being reversed and drum brakes really suffer going backward. Discs won't fully solve that issue since they are very small and the reason for that is again, bias. Front brakes do front brake work, rear brakes do rear brake work. The fronts are designed to handle the weight transfer onto the front axle and with rare exception, are much "larger" than rear brakes. This is due to most of our stopping being done while going forward. When that is reversed going backward, the rear brakes are easily overpowered. Tie them together through the t-case and all the problems are solved.
 
It's also possible only one front wheel is locking up. I would imagine it's next to impossible to lock up both of the front wheels at the exact same brake pressure due to variations in load on the left and right tires and variations in traction on the driving surface (unless a limited slip or locking differential was involved).

In that case, a front tire could still slip in 4WD, though there should still be an improvement in braking power.

Locking up both tires causes a loss of steering, and in reverse, locking the front tires could easily cause a fishtail.

Could ABS (or possibly a lack of) be exacerbating the issue?
 
It's also possible only one front wheel is locking up. I would imagine it's next to impossible to lock up both of the front wheels at the exact same brake pressure due to variations in load on the left and right tires and variations in traction on the driving surface (unless a limited slip or locking differential was involved).

In that case, a front tire could still slip in 4WD, though there should still be an improvement in braking power.

Locking up both tires causes a loss of steering, and in reverse, locking the front tires could easily cause a fishtail.

Could ABS (or possibly a lack of) be exacerbating the issue?
Stop imagining, find a safe, low traction hill to back down and have someone watch the front tires when they lock up.
 
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