2nd Gen Non-Engine/Transmission 01 or 02 disk brake rear differential in 98

[johnjackson]

Has anyone swapped a 2002 disk brake rear end into a 1998 and what problem were in-countered? Thanks for any advice. john

 

[KATOOM]

Its not a straight forward swap because of the proportioning valves and master cylinder are not the same. And.....its not worth the effort because the drum brakes were just as strong and the discs were more prone to corrosion problems.

 

[johnjackson]

Thanks Katoom. I wondered about master cylinder and proportioning valve. I just changed both front wheel bearing hubs and replaced brake pads with the best O'Reilly auto had and It stops great now so swap headache not worth it. John

 

[Regcabguy]

Pretty decent braking with the Dana 80.

 

[KATOOM]

Making sure the drums are adjusted helps as well. Sometimes just using the e-brake while rolling backwards will let the star adjusters click. But sometimes the star adjusters are corroded or stuck and wont adjust whereby you have to manually adjust them.

 

[RustyJC]

And.....its not worth the effort because the drum brakes were just as strong and the discs were more prone to corrosion problems.

I'll just say this - I towed 5th wheels with a 1996 3500 and a 2002 3500. There was no comparison in braking between the two - the 2002 was FAR superior to the 1996. Unlike the 1996, I never had any problems with brakes in 9 years of ownership of the 2002 - it still had the original pads when I sold it.

Rusty

 

[KATOOM]

I'll just say this - I towed 5th wheels with a 1996 3500 and a 2002 3500. There was no comparison in braking between the two - the 2002 was FAR superior to the 1996. Unlike the 1996, I never had any problems with brakes in 9 years of ownership of the 2002 - it still had the original pads when I sold it.

Rusty

That would be expected since the brakes were upgraded as the model years got newer. For instance, pre-2000 had single piston calipers whereas the following year had dual piston calipers. And the 2nd gen automatic transmission trucks had lighter weight brakes than the manual transmission trucks.

 

[JMcCoy]

I swapped out my rear drum brake Dana 70 for Disk brake Dana 80. It was an easy swap, and 100% worth it! I would do it 10 times over. Since mine is a 2500 with the height sensing proportioning valve (always pinned up), I just took it out and bypassed it. Since I went from a Dana 70 to a Dana 80, I needed to replace my spring perches, U-bolts, and shorten my driveshaft by 1.5 inches. Ones with a 3500, you will not need to do this. I'm glad I did, since my U-bolts were almost rusted through. I flipped my U-bolts around to mount them the way they should have been from the factory. You will also need a to get the right length e-brake cable.

The truck now stops way smoother. The rears will lock up if I slam on the brakes while running empty and the surface is wet. Not bad though. Here is the thing. I am currently running 92-94 Ford brakes, which have more braking power then the 94-99 Dodge garbage. You would probably need more proportioning. I would put a proportioning valve in (probably adjustable) but I am going to wait until I upgrade to the 95-97 Ford Brakes. They are a little bigger and will probably balance my brake proportioning.

There is just no comparison between brakes and drums. Yes even well adjusted drums. Prior do doing the swap, I ran the GM wheel cylinders for several years. They did make a big difference, and I would recommend them to anyone not wanting to swap to disk.


Summery:

If you already have a Dana 80:
-Add brake proportioning to the rear
-Get correct length e-brake cable
-New U-bolts (recommended)

Dana 70 drum to Dana 80 disk swap:
-Above plus
-Replace Dana 70 spring perches for Dana 80 perches
-Shorten Drive shaft by 1.5 inches.

As far as master cylinder goes, there is no issue. A 2001-2002 master cylinder has a smaller piston. The smaller piston translates to increased brake pressure (and more petal movement). I have yet to swap my master cylinder since mine works just fine. When my master cylinder finally goes out, I will install one from an '02 to give me a slightly softer petal.

 

[KATOOM]

I just dont understand why my stock brakes rear drum truck stops so good. Not only do the brakes work smooth but if I lay into the brake pedal hard and you're not wearing your seatbelt then odds are that you'll be out of your seat. Granted, I dont abuse my brakes, corrosion is not a problem where I live, and I know the rear drums are adjusted. Plus I make sure to use the e-brake every now and again while rolling backwards, which helps release the star wheel so it will move. Whatever the case.....

 

[JMcCoy]

I just dont understand why my stock brakes rear drum truck stops so good. Not only do the brakes work smooth but if I lay into the brake pedal hard and you're not wearing your seatbelt then odds are that you'll be out of your seat. Granted, I dont abuse my brakes, corrosion is not a problem where I live, and I know the rear drums are adjusted. Plus I make sure to use the e-brake every now and again while rolling backwards, which helps release the star wheel so it will move. Whatever the case.....

I thought mine stopped pretty good as well. Sometimes you just don't know what you don't know. There is no comparison. Drum brakes should have gone away in the 60's. Also, keep in mind that you have better front brakes then the OP. You are fortunate to have the option to swap front brakes from a 2010.

 

[KATOOM]

But I do have other comparisons as this is not the only truck I've driven. I've been driving for long time, been behind the wheel of many vehicles, and have driven plenty with poor brakes. This truck has what I'd consider to be more then adequate brakes for its size and capacity. They're definitely not as superior when compared to some of my newest vehicles but then again I'm also understanding that this is a 4 ton truck.

Yes, I'm glad you acknowledged that there is a difference in the later 2nd gen trucks and especially the manual transmission 2500 ones too which have the same brakes as the 3500 trucks. Surprisingly many people dont know this.

Too bad you dont like drum brakes either because they can be VERY strong. Stronger than discs too but just cant dissipate heat nearly as fast.

Check out how good they can work.....

https://www.youtube.com/watch?v=P-giC24SxwE

 

[GAmes]

It's been explained on past TDR articles, it isn't the brakes that stop you, it is the tires. Comparing two different trucks with two different tires size and types doesn't mean anything. If the brakes are functioning as designed, disc brakes are no better or worse in stopping power than drum brakes are. They do have some pluses, but stopping power isn't one of them. A long time ago I bought a new '85 Silverado. At that time GM was putting Uniroyal Tiger Paws on their pickups. I couldn't pull an unloaded boat trailer up the ramp with them. With less than 1000 miles on the odometer I replaced them with BF Goodrich tires and never spun out on a boat ramp again. A friend of mine thought he hit the jackpot when he bought a nearly new set of Tiger Paws for a very low price a few years later. I tried to warn him, but he was ecstatic about the great deal. The first time it rained he slid through an intersection and very nearly t-boned another car.

I'm with KATOOM. My stock brakes work just fine. The automatic adjusters don't, but when the park brake pedal doesn't hold I crawl under there and spin the star wheel a few clicks and all is well.

 

[SAndreasen]

I just dont understand why my stock brakes rear drum truck stops so good. Not only do the brakes work smooth but if I lay into the brake pedal hard and you're not wearing your seatbelt then odds are that you'll be out of your seat. Granted, I dont abuse my brakes, corrosion is not a problem where I live, and I know the rear drums are adjusted. Plus I make sure to use the e-brake every now and again while rolling backwards, which helps release the star wheel so it will move. Whatever the case.....

I bet bet the brake nomes put ford brakes on it for ya whilst you slept?

 

[JMcCoy]

That person was lucky that trucker was on point. I agree drums have and still do have their place. They can be made to work good enough. Disks transition better and apply smoother, with a wider braking (power) band, before locking up. I am familiar with drums, as I have had many vehicles with them. Heck, all vehicles had them at one time. I currently have 2 motorcycle with drums front and rear, one with disk front and drum rear, and one with disk front and rear. Guess which one stops the best. I know different vehicles, but same concepts. And yes, tire ultimately translate the braking force, if properly applied.

With all that said, I changed over to disks because I wanted a Dana 80 with 4:10 gears. If I had not been looking for different gears and axle, I may not have spent the money. I would still recommend them to anyone who had access to a disk brake axle for a reasonable price.

Maybe the 2017 Rams will come out with Drums... LOL!

 

[KATOOM]

I'm not trying to argue that drums are better than discs, nor by saying that am I implying that discs are better than drums. Thats not the point of the topic, but rather discussing that the rear discs on the 2nd gen trucks are not worth the effort to swap over from rear drums. They're no stronger and they're more prone to problems than the rear drums of those year trucks. Just because you feel your situation resulted in something better doesnt mean all the other members who've said otherwise are mistaken. This isnt meant to insult your intellect either but maybe there was something wrong with your brakes and the swap only brought light to that.

Hey, we could hash out forever the differences between disc and drum brakes with examples and opinions which again, isnt the point. Both have their place in certain applications. Heck, what I'd like to see make its way into the automotive industry is dynamic braking.

 

[MLee]

I swapped out my rear drum brake Dana 70 for Disk brake Dana 80. It was an easy swap, and 100% worth it! I would do it 10 times over. Since mine is a 2500 with the height sensing proportioning valve (always pinned up), I just took it out and bypassed it. Since I went from a Dana 70 to a Dana 80, I needed to replace my spring perches, U-bolts, and shorten my driveshaft by 1.5 inches. Ones with a 3500, you will not need to do this. I'm glad I did, since my U-bolts were almost rusted through. I flipped my U-bolts around to mount them the way they should have been from the factory. You will also need a to get the right length e-brake cable.

The truck now stops way smoother. The rears will lock up if I slam on the brakes while running empty and the surface is wet. Not bad though. Here is the thing. I am currently running 92-94 Ford brakes, which have more braking power then the 94-99 Dodge garbage. You would probably need more proportioning. I would put a proportioning valve in (probably adjustable) but I am going to wait until I upgrade to the 95-97 Ford Brakes. They are a little bigger and will probably balance my brake proportioning.

There is just no comparison between brakes and drums. Yes even well adjusted drums. Prior do doing the swap, I ran the GM wheel cylinders for several years. They did make a big difference, and I would recommend them to anyone not wanting to swap to disk.


Summery:

If you already have a Dana 80:
-Add brake proportioning to the rear
-Get correct length e-brake cable
-New U-bolts (recommended)

Dana 70 drum to Dana 80 disk swap:
-Above plus
-Replace Dana 70 spring perches for Dana 80 perches
-Shorten Drive shaft by 1.5 inches.

As far as master cylinder goes, there is no issue. A 2001-2002 master cylinder has a smaller piston. The smaller piston translates to increased brake pressure (and more petal movement). I have yet to swap my master cylinder since mine works just fine. When my master cylinder finally goes out, I will install one from an '02 to give me a slightly softer petal.

I have never heard of this kind of replacement, a later year for a earlier model truck with a smaller master cylinder bore. Wonder if this would work on mine. I'm having a master cylinder problem of keeping a good pedal versus a lower than average pedal, when you need that extra pedal travel.

 

[JMcCoy]

I have never heard of this kind of replacement, a later year for a earlier model truck with a smaller master cylinder bore. Wonder if this would work on mine. I'm having a master cylinder problem of keeping a good pedal versus a lower than average pedal, when you need that extra pedal travel.

I don't believe a smaller bore master cylinder will solve your problem. It may make it worse with the increased travel of the smaller piston. If pedal height is your issue, you probably just need to adjust the star wheel on your rear drums. A good bleeding (RR, LR, RF, then LF) wouldn't hurt either.

 

[RWherley]

One of the things that helps you guys with later 2nd gens have good breaks is your hydro power boosters, they are much better then the old vacuum boosters on the old trucks