2nd Gen Non-Engine/Transmission Rear axle swap: '01 with disc brakes into a '98?

[JGK]

Simple questions. Can I swap out my '98 Dana 80 LS axle with drum brakes for an '01 (or later) equivalent axle with disc brakes? Did the newer axles use the proportioning valve like my '98? Will my parking brake work with it? What issues will I have to deal with to do it?



Thanks!

-Jay

 

[Vaughn MacKenzie]

For one thing, the axle will be wider and will track slightly outside of your front wheels. I think you do need to swap the proportioning valve. weak96ram on NW Bombers was able to do the swap (a 2001 axle into his '99) and didn't run into too much trouble but didn't like the Texas 2wd look of his rear tires sticking out a bit.



Vaughn

 

[Forrest Nearing]

did the front hubs have a taller hat on them too?

 

[JGK]

So Vaughn, is the wider look due to the brake assemblies or is the axle actually a bit wider? I'd have to agree that I don't think I'd go for that look.



All I'm really trying to do here is weigh the differences between swapping axles and simply doing the EGR rear disc conversion. The EGR option cost is pretty much fixed. The swap is variable depending on what can be found for what price.



Thanks,

J.

 

[Joe Mc]

I'm considering a similar swap, but for more reasons than just the rear discs. I have an open end and need a posi too - the discs are very desirable and it's easier to swap the whole unit out than just the pieces and parts. But, I too would like to know why the difference in width; is the housing wider? Why do the wheels stick out more? Could this be rectified with different offsets on the rear wheels?

 

[Jahcad]

I would say it is the rim offset. The e-brake pedal,cables are all different and the rubber line coming off the frame to the axle is different; and the proportioning valve is to. I would try to get the master cylinder too for the bigger resivor because of the larger fluid capacity rear calipers.

 

[Forrest Nearing]

I would say it is the rim offset.

ok, but 01. 5-02 trucks don't have wider rear track than front... so if the rear axle is wider w/ disk brakes, do the front rotors have a taller hat on them or what?



I ask because I've got an '02 3. 54 LS D80 that I'm going to be putting in my 98

 

[zstroken]

If it was a dana 80 out of a dually then i can see it being wider. The SRW I think have the same all the way thru. I put a cab and chassis rear in my 97 and it is slightly narrower.

 

[Forrest Nearing]

Vaughn said it did... mine is a 2500 rear going into a 2500

 

[Jahcad]

Ya the hole front knuckle is different with the larger caliper and with the rotor on the out side of the hub assembly.

 

[JGK]

TTT...



Forrest, I've found a D80 from an '02 as well and did some measuring. It appears that overall, the wheels will stick out about 1/2 inch on each side. The discs makes the whole assembly about 1" wider than the D80 with drums.



Vaughn, I PM'd weak96ram about his swap. That was a D70 and in his case, the wheels were pushed out farther. But he couldn't offer any more info that would help me in this project.





I still have a few more measurements to make, but it appears it will work. Not sure about the parking brake cables, but if needed I'd think you could make an adaptor or have stops swagged on by a cable shop.



Right now, my question is the master cylinder. It appears my '98 may be a different size that the '02. Does anyone know if this is indeed an issue? Is it simply a matter of replacing mine with one from an '02? Is it a simple swap or are adaptors of some sort needed (purchased or fabricated)?



Thanks,

-Jay

 

[Forrest Nearing]

Jay,



when I got my rear, I got the e-brake cables, the master cylinder, and the proportioning valve.



It has been my experience with converting various cars from rear drums to disks, you must change the master cylinder or you will have less rear braking capability than you did with the drums.



the master for the disk brake trucks is much larger.



I'm debating actually doing the disk brake install at this point. my truck stops pretty well, and it might be easier at this point to just swap the drums off my D70 onto the D80 and roll

 

[NVR FNSH]

Ya the hole front knuckle is different with the larger caliper and with the rotor on the out side of the hub assembly.

The changes to the front axle/steering components changed the track width of the front - thus the change to the rear. Rim offset changed from pre '99 to '00 later because of the front axle changes.



I ran into the width change when I bought a set of Rickson's off a '98 and they stuck out ~1. 5" too far on my '00 - just like Rickson said they would... .



Fortunately for my dad the Rickson's fit perfect on his '96.



Brian

 

[CrewCabDiesel]

For what it is worth I did the same swap to my 2001 DRW without any problems. All I had to change was a short piece of the e brake cable which cost me $20 at the dealer. I went to the dealer first and checked parts numbers on the master cyclinder and proportining valve between a drum brake truck and a rear disk brake truck, they were both the same parts numbers for drum or disk for 2000, 2001 and 2002 one ton trucks. On the duallys, they went to rear disk brakes 2001. 5 as for 3/4 I don't know what the first year was for rear disks.

On your truck I would do the same, cross check your master cyclinder and other parts with a newer year with rear disks, I would use the 2002 model year for best results, 2003 and up is a completely different axle made by American axle not Dana.

As for track with, when in doubt get out a tape messure.

Kyle

 

[JGK]

Forrest,



What you say makes sense. I spoke with a brake mechanic at one of the local DC dealerships (hold the hoots, please). He seemed fairly knowledgable and drives an '01 6-speed. He said the '02 D80 should bolt right up and not require a master cylinder change. But the swap may be the best approach.



Will a master from an '02 be a fairly simple swap out in my '98 without issues with the ABS (mine's rear only) or anything else?



It makes me wonder how EGR Brakes does it. I don't think they address the master cylinder change with their disc kit.



I'll visit the dealership again and cross check cylinder info.



Thanks!

J.