1 more question: did you remove the proportioning valve? And if so, can you lay on the brakes hard without feeling like the rear end is going to come around? Sorry for all the questions, but I am starting down this road and I am trying to make a battle map......Mark sorry that was 2 questions

 

No the only thing I removed was the "dump" valve located over the rear axle inside the frame rail. Removed that valve, but left the prop valve up front near the master cylinder.

When it is wet and no weight in the bed and you jam on the brakes you do have to be careful with the rear wheels locking up. But at least I don't have to worry about loosing brakes completely when loaded with a trailer, that to me is more important.

 

[QUOTE=But at least I don't have to worry about loosing brakes completely when loaded with a trailer, that to me is more important.[/QUOTE]

Well said, I could not agree more...Mark

 

Has anyone tried a disk brake rear diff off a later second or early third gen?

 

I have a disc brake 80 in mine. I noticed no difference in braking performance when I swapped out the original 70 with 3x12 shoes, front brakes do most of the work anyway. First drive after the install was interesting, took it out of the shop and just touched the brakes and my buddy almost hit the windshield. This is with a 2nd gen hydroboost installed using the original 93 power steering pump.

 

My 1985 Ford DRW F350 with economy-grade pads/shoes will put your head into the windshield and stop on a dime.

My old 1978 K20 Chevy makes the Ford feel like it don't have any brakes.

All of the 1st Gen. Dodges around here barely have any brakes at all.


We were recently messing with the wife's D-250 with the rear wheels off the ground.

With the rear wheels spinning, no matter how we applied the foot-brake, the wheels just kept going.

There is no brake function whatsoever on the rear wheels, which is most likely why her front pads/rotors wore into razor-blades in short order.


I am remedying that as soon as it will quit coming these pop-up storms/showers.

 

http://www.pirate4x4.com/forum/showthread.php?t=746609

Try this guy, I think he gets around 500 for a disk conversion with p brake, 300 or so without p brake.

 

Unless the piston sizes and numbers are matched front to rear, you need the prop valve. Even more so with rear disks, because they grab harder than the drums. That's why MOPAR changed over to front disks when they did with the A-bodies. They sent a 383 Dart to Indianapolis to pace the 500, and the rears locked on the 4-wheel-drum brakes, and the pace car crashed on pit road.

Not having any better brakes after a disk swap may be a proportioning issue.

 

I replaced EVERYTHING in my truck with brand new O'Reilly lifetime stuff.

I upgraded the rear shoes (with new drums) to 1ton 3" wide ones. The hardware and cylinder were from a 250/ 3/4ton.

I also bypassed the RWAL.

Also the lines on the rear axles.

I made sure the master cylinder rod was adjusted correctly and the rear shoes.

My truck would stop sooner than my 4k lbs 4 disc boat known as a Crown Vic.

And the car stopped!

 

how do you properly adjust the master cylinder rod??

 

To do it over, I would get the two already paired. I think I got mine close, I'm not sure. I turned it out til I thought I saw a little gap, then turned it back in just a little.

 

my 90 and 92 brakes work great!

 

I don't know what the secret is. It seems that some trucks stop great and some don't. For mine I think i'm going to do the disc upgrade in the rear and bypass the abs system. I also thot I would ditch the prop valve and install an adjustable one for the rear. I do think that our front brakes are a little antiquated. I'm talking about the caliper slides. I have all new brake stuff on all four corners, plus new master and booster. But my pedal is too soft for me. About two months ago I had the front end apart and I decided to clean the caliper slide contacts on the bracket and caliper with a sander and I regreased them. After that the pedal was a little more firm. About a week after that it went right back to where it was. I'm with Mark. I will have good breaks someday. I'll figure something out.

Jake

 

It is my understanding that what we are calling a proportioning valve on the un-altered RWAL trucks is not a proportioning valve at all, but simply a multi-ported block; am I right ??

 

No, it is a proportioning valve. Dodge calls it a combination valve because it has a sender unit also that turns on the brake light when there is a problem. I believe that all combo-disk/drum setups needed them to delay the application of the front disks a tad, to prevent spin-out...Mark