Rear disc brake conversion

[Pete Whitstone]

Decided to forge my own trail rather than buy a kit. I'm just a glutton for punishment that way most times. I sourced an entire Dodge Ram 1500 rear axle of 2013 vintage off FB marketplace for cheap, then set about adapting the Dodge stuff to the 9 inch. It actually turned out to be not that difficult, but it did require some machining so I can't really recommend it as an easy solution. Specifically, the 4 Dodge mounting holes had to be welded up so the 9 inch pattern could be drilled partially on top of the Dodge holes. Then the center hole where the axle passes through had to be bored out about .400 larger. Then the caliper mounting brackets had to be sawed in half so they could be welded onto the other side of the 9 inch flange.

Some photos to clarify.

This will allow not only the conversion to discs, but also retain the parking brake function with some shoes that fit inside the rotor hat.

Minor fiddly things yet to work out are how to interface the parking brake cables at the Ford end, how to make the Dodge rotors hubcentric, and so on, but that stuff should be pretty simple.

The rotor dictates a larger wheel size than 15", that's one downside. But I have a set of 17" wheels (which, coincidentally are Dodge as well) that I run on the truck sometimes. That will have to become full time.

More to come as the conversion progresses.

Slowly getting more stuff done on this. I got the caliper bracket machined and welded to the other side. I had some confusion with that because the caliper brackets are the same, side to side, rather than being mirror image of each other. It's been a while since I took them off the Dodge rear axle. It turns out that Dodge was clever with their economy and used the same part on both sides for almost all this stuff. So that has the emergency brake cable attachment pointing towards the front of the truck on one side, and pointing to the rear of the truck on the other side - how would that work????

I looked at some diagrams and figured out that they rotate the caliper brackets 180 degrees on the axle. This points the cable attachment point back towards the front of the truck, but puts it on the TOP of the axle, where on the other side it puts it on the BOTTOM. Genius or evil, you decide, but that's the way they did it.

With the caliper brackets welded on both sides, I could move on to the next part, which was the brake backing plate. This mounts the mechanical parking brake stuff. In the dodge application, it gets sandwiched between the caliper mounting bracket and the nuts that hold the whole thing together. In this application, I could have sandwiched it similarly between the caliper mount and the Ford flange. But that would mean a couple things. First, I would have to cut it in half to make it fit over the Ford flange, and second, the caliper bracket is welded to the Ford flange, so once it was in there, it could never be replaced.

So instead it made more sense to just cut the hole bigger to make it fit over the Ford flange. Here is one that has been cut out (left) and an uncut one.

And how it fits over the Ford flange.

Originally 3 bolts held the backing plate to the caliper bracket. Cutting out the center like that eliminated one of those bolts. That bolt hole is circled here. As you can see, it is within the portion to be cut out.

To restore that strength, I added a 3rd bolt back bu drilling and tapping the caliper bracket in an area that would not affect anything. That is the bolt with the gold colored head shown here, in about the 5 o'clock position, near the brake shoe expander.

I need to get the other side this far along, then I can look at actually getting this installed in the vehicle.

 

[ArdWrknTrk]

Slowly getting more stuff done on this. I got the caliper bracket machined and welded to the other side. I had some confusion with that because the caliper brackets are the same, side to side, rather than being mirror image of each other. It's been a while since I took them off the Dodge rear axle. It turns out that Dodge was clever with their economy and used the same part on both sides for almost all this stuff. So that has the emergency brake cable attachment pointing towards the front of the truck on one side, and pointing to the rear of the truck on the other side - how would that work????

I looked at some diagrams and figured out that they rotate the caliper brackets 180 degrees on the axle. This points the cable attachment point back towards the front of the truck, but puts it on the TOP of the axle, where on the other side it puts it on the BOTTOM. Genius or evil, you decide, but that's the way they did it.

With the caliper brackets welded on both sides, I could move on to the next part, which was the brake backing plate. This mounts the mechanical parking brake stuff. In the dodge application, it gets sandwiched between the caliper mounting bracket and the nuts that hold the whole thing together. In this application, I could have sandwiched it similarly between the caliper mount and the Ford flange. But that would mean a couple things. First, I would have to cut it in half to make it fit over the Ford flange, and second, the caliper bracket is welded to the Ford flange, so once it was in there, it could never be replaced.

So instead it made more sense to just cut the hole bigger to make it fit over the Ford flange. Here is one that has been cut out (left) and an uncut one.

And how it fits over the Ford flange.

Originally 3 bolts held the backing plate to the caliper bracket. Cutting out the center like that eliminated one of those bolts. That bolt hole is circled here. As you can see, it is within the portion to be cut out.

To restore that strength, I added a 3rd bolt back bu drilling and tapping the caliper bracket in an area that would not affect anything. That is the bolt with the gold colored head shown here, in about the 5 o'clock position, near the brake shoe expander.

I need to get the other side this far along, then I can look at actually getting this installed in the vehicle.

Man, that's some hardcore fabricobbling to make it work with your 9" v/s working with a later disc brake rear that might need the lug pattern modified.

Glad you're close to getting it back under the truck!

[Pete Whitstone]

Slowly getting more stuff done on this. I got the caliper bracket machined and welded to the other side. I had some confusion with that because the caliper brackets are the same, side to side, rather than being mirror image of each other. It's been a while since I took them off the Dodge rear axle. It turns out that Dodge was clever with their economy and used the same part on both sides for almost all this stuff. So that has the emergency brake cable attachment pointing towards the front of the truck on one side, and pointing to the rear of the truck on the other side - how would that work????

I looked at some diagrams and figured out that they rotate the caliper brackets 180 degrees on the axle. This points the cable attachment point back towards the front of the truck, but puts it on the TOP of the axle, where on the other side it puts it on the BOTTOM. Genius or evil, you decide, but that's the way they did it.

With the caliper brackets welded on both sides, I could move on to the next part, which was the brake backing plate. This mounts the mechanical parking brake stuff. In the dodge application, it gets sandwiched between the caliper mounting bracket and the nuts that hold the whole thing together. In this application, I could have sandwiched it similarly between the caliper mount and the Ford flange. But that would mean a couple things. First, I would have to cut it in half to make it fit over the Ford flange, and second, the caliper bracket is welded to the Ford flange, so once it was in there, it could never be replaced.

So instead it made more sense to just cut the hole bigger to make it fit over the Ford flange. Here is one that has been cut out (left) and an uncut one.

And how it fits over the Ford flange.

Originally 3 bolts held the backing plate to the caliper bracket. Cutting out the center like that eliminated one of those bolts. That bolt hole is circled here. As you can see, it is within the portion to be cut out.

To restore that strength, I added a 3rd bolt back bu drilling and tapping the caliper bracket in an area that would not affect anything. That is the bolt with the gold colored head shown here, in about the 5 o'clock position, near the brake shoe expander.

I need to get the other side this far along, then I can look at actually getting this installed in the vehicle.

This conversion is almost complete. No testing on it yes as I am currently building a new engine for the truck. Basically the only things left were getting everything assembled and the items below:

1. Fabbing up rings to keep the rotor centered on the Ford hub. This could have been done with a central ring around the axle hub protrusion, or with 5 small rings around each of the axle studs. I went with the 5 smaller rings because I found some tube/pipe that was the right OD and ID. It just needed a half inch drill run thru it to get rid of the seam on the inside.

2. The parking brake cables were compatible with the Ford setup, for the most part. The Dodge setup has a long side and a short side, then an intermediate cable connects both of those to the pull mechanism. I ordered 2 long (passenger side) cables, and they worked fine at each end. Obviously they fit at the brake end, but to my surprise they also fit at the Ford end. The adjuster had to be tightened quite a bit, but still within its limits, there is a small amount of thread left on the Ford adjuster.

3. I have a disc/disc combo valve that I need to swap in, along with the new MC. I will also install a manual proportioning valve on the rear brake outlet after the combo valve. Then bleed the system.

I will have more updates after the truck is back on the road in a couple weeks.

[ArdWrknTrk]

This conversion is almost complete. No testing on it yes as I am currently building a new engine for the truck. Basically the only things left were getting everything assembled and the items below:

1. Fabbing up rings to keep the rotor centered on the Ford hub. This could have been done with a central ring around the axle hub protrusion, or with 5 small rings around each of the axle studs. I went with the 5 smaller rings because I found some tube/pipe that was the right OD and ID. It just needed a half inch drill run thru it to get rid of the seam on the inside.

2. The parking brake cables were compatible with the Ford setup, for the most part. The Dodge setup has a long side and a short side, then an intermediate cable connects both of those to the pull mechanism. I ordered 2 long (passenger side) cables, and they worked fine at each end. Obviously they fit at the brake end, but to my surprise they also fit at the Ford end. The adjuster had to be tightened quite a bit, but still within its limits, there is a small amount of thread left on the Ford adjuster.

3. I have a disc/disc combo valve that I need to swap in, along with the new MC. I will also install a manual proportioning valve on the rear brake outlet after the combo valve. Then bleed the system.

I will have more updates after the truck is back on the road in a couple weeks.

You're making great strides!

I just blew up the rear end in my truck and had considered a disc brake D60 axle from an E-series as an alternative, im happy with my drums for now.

Adapters and stud bushings might be okay for a 150. I don't think id travel this path with the abuse my 250 sees.

Please detail the manual brake bias valve you're using.

This might be handy for > 8600 users who don't want to deal with the hinged load valve, but it wouldn't self adjust.