P15-D24 to 95-2001 Explorer Disk conversion.

I was having a hard time with a low gear ratio and poor brakes on my 47 P15 Plymouth. It was time for a trip to the wrecking yard so off I went. I was really looking for a rear end for the car to get my gear ratio to about 3.5-3.73 to 1 instead of the 4.11s that are stock for my car. I have shorter than stock tires on the thing and that makes it even worse. While looking at a rear end in a 96 Ford Explorer I noticed that the rotors and calipers might make for a good swap onto my car without too much expense or effort.
I went home that day with only ideas in my head and some measurements of the rear ends (drum vs. disk) in the Explorers. Oh and a few pictures of how the front brakes are mounted etc...
A day or two later I went to a yard out of town due to a much lower price and found that the rear end they had (with disks) was a 4.10 gear ratio so instead I took home the calipers and rotors off the same rig.
This is where I started.

 

So the first thing I had to do was figure out how I was going to make the brackets for the calipers and get the rotors on the car. This was a test of my faith that it was going to work without a lot of fact finding and measuring.
I started by pulling off the passenger side hub and drum assembly (all work was done from the passenger side and the drivers side was just a bolt and drive deal since the brackets work on both sides).


The next step was to grind off the rivets that hold the drums to the stock hubs and seperate the two. Then grind the rivets flush to the hub surface since they would not hammer out of the hub plate.


The backing plate had to come off for measurement of hole spacings for the brackets to bolt to the spindles. To remove the backing plates you just unbolt the 2 upper and lower cam bolts that allow you to adjust the shoes and take loose the hard line where it meets up with your flex line at the frame then take off the clip that holds the flex line in place. This will let you take the backing plates with shoes and all off at one time.

 

After removing the old drums from the hubs and the old brake hardware from the spindle I cleaned up the spindles and reinstalled just the hub.


The calipers and rotors I purchased were a little rusty so without thinking about it I found that I was lucky they were like this. More on that later. Here is a picture of what the assembly looked like for the trial fit of the rotor on my hub and kind of looking for interference with the caliper or rotor and my stock stuff.


The hole center worked great for the hub and caliper. No machine work for the hole to fit over the hub. Also with the caliper to the rear there is no real issue other than if I want to take off the nut for the tie rod. If I need to do that the caliper will have to be unbolted. Oh well I can live with that. On to making the caliper bracket.....

 

More about the rusted calipers and rotors. The reason it was a good thing was it held the caliper in the stock position as if it were still mounted to the Explorer. The first one I worked with accidentally came loose mid way through making the aluminum template so I hot glued the one that was actually supposed to go on the passenger side and proceded to make the following brackets. From searching around a bit I find that most people that have converted to disk have 3/8 plate steel brackets so I went out and purchased some rems at the local steel supply company in town and went to work. I started with cardboard and worked my way to plate steel.

Using cardboard I made a piece match the back of my drum backing plate so I could mark out the holes for the spindle.

I then fashoned what would be a close match to my finished shape and marked out what I thought would be closest to fitting around my kingpin. I took the cardboard template and marked it out on a piece of old road sign aluminum for my first attempt at the bracket.


In the picture you will see that there are 2 holes for mounting the caliper and 3 for the spindle. The holes for the caliper ended up being wrong. Ill fix them later. Eyeballing the thing you just dont get it right the first time every time.

 

So as I mentioned the thin aluminum bracket was not drilled right for caliper holes. What to do? What to do????
On comes a light bulb! I purchased 2 bolts to go in the caliper and cut the heads off. I stuck them in the drill and spun the drill with one hand while I used the angle grinder to put a point on them with the other hand. Here are the finished bolts.


I screwed these into the caliper


then mounted a new aluminum plate with just the spindle holes drilled and then mounted up the caliper and rotor combo. I screwed the bolts out to touch the new plate and then lined up the caliper where I wanted it. I then used a hammer on the back side of the aluminum plate and like a center punch it made a dimple. Same thing with the other bolt and I had perfect marks for where the holes should be. No Guessing!

 

I drilled out the new aluminum bracket template and then put it on for a test fit. Looks to be just right.


Now its time for the big stuff. I transferred the template to the 3/8 plate steel and took it to a friends to cut out since I dont have a torch. I made a total of 4 blanks and used 3 before I got both sides just right. Here are the before and afters of the first bracket.


Then after a little fitting here is what it looked like on the spindle.


One issue that you will notice (I knew this from one of my first test fits) is that there is going to be a gap between the caliper mount and the new bracket.


Its about 3/8 of an inch. Hmmm. What a coincidence. I happen to have some 3/8 plate to fill that gap. No need for bending the bracket. I just made a spacer with 2 holes in it for the caliper bolts to fill the gap. It doesnt have to be perfect since these calipers seem to floating calipers. The facatory bolts from the explorer worked perfectly with the brackets and spacers.

 

After getting everything lined up and a little more trimming and red paint so forum members could see the bracket better.


Then with everything bolted on.

 

The new brackets went behind the spindle. The bolts that held the original backing plates on were an odd headed, cammed 9/16 bolt. They also held the steering arms to the spindles. By adding the brackets the bolts need to be longer but I did not need to drill the holes out or do anything special to the spindles or the steering arms. Also I had mentioned taking out 2 bolts to remove the backing plates. There is a third bolt that will have to be removed to mount the new bracket. It is the second one that holds the steering arm on. This one (on each side) never really moves so like most bolts that have been in the car for 60+ years its a little more difficult to remove. A big hammer was in order for me to get these bolts out. I found some 9/16 bolts at the local hardware store. They are a grade 8 bolt not the more common grade 3. Make sure to get a better than grade 3 bolt to replace the factory ones.
I used the factory bolts for the calipers to bolt them to the new brackets.
Just for interest purposes I thought people might want to know the fit of the plate of the original hub inside the new rotor.


Also 3 other things to do. When you add the brackets you move the steering arms in 3/8 of an inch on each side. This will move the toe of the front wheels "in" by a whole bunch. I needed to adjust the tie rods in on both sides so the toe was close, then get a front end alignment if you dont have the ability to do the toe yourself. I was able to do it myself.

Next is studs. The car originally came with wheel bolts. not studs. I already had studs on the car because of the mag wheels I had put on the car. You can drill the holes out slightly and pull new studs through the back of the hub.

The last thing is the flex lines. They will need to be moved behind the upper control arm and shock. I used a flex line I found at the auto parts store back room. I believe its from a Mazda 3. I used the original mounts and just drilled and tapped 2 new holes in the frame for the bolts. I made sure to put it back a ways. I plan on installing the F1 shock mounts to relocate the upper part of the shock to the frame rather than the stock upper control arm. I had to extend the passenger side to reach but had recently put in new lines in the front so I just re-bent the line on the drivers side to match up to the new location.

 

So are you using the explorer rear brakes on the front of the car? Have you driven the car with tis set up? Are you willing to share your bracket templates or to produce some brackets for sale?

 

Its the front brakes from the Explorer on the front of my car. If you would like I can scan my rough template and pm a copy to you.

I am still in the test drive stages. I have been driving with this setup for several weeks now and everything seems to be going (or stopping) well.

 

This is hot rodding at its best! thanks for sharing. Buy the way how do they work?
are you using a proportioning valve?

 

Nice work!

 

One additional that should be added here. This was done with a set of factory "Directly off of the Explorer" brakes. I have had a couple of reports that the "some" replacement rotors have a slightly smaller than factory hole on the back side of the rotor so the outer diameter of the hub could be turned down about 1/16 of an inch so it wont matter what brand or style the aftermarket replacement rotors are.

 

Great tech!

 

I would be very interested in a scan of the template....I'm not looking to make any money of them I'd just like to make my car stop better. I'm in the middle of the upper shock re-location and switching to Aerostar coil springs because mine were heated and clamped years ago and ride like crap!

Great tech thanks for sharing!

 

Were these 2 or 4 wheel drive calipers?

 

The calipers were off of a 4wd. If you get new calipers some manufacturers dont machine the disk center out as far on the back side so you may need to have your hub machined slightly to have yours fit. That way it doesnt matter what one you purchase the rotor will always fit. I got my rotors off of a wrecking yard car and it had factory rotors on it so they fit right on.
Heres the link to the page with the scans.
http://car.icompute.info/disk_bake_bracket.htm

 

Awesome I've already sent those images to my CNC plasma guy! I also priced out my calipers and rotors from rockauto.com. thanks again

Sent from my DROID device using the TJJ mobile app

 

No problem. I know that the spacing works but isnt necessarily perfect. The brackets were back yard done ya know. Just so everyone knows. They only work on the P15 spindles. The Dodge and Desoto spindles had a slightly larger pattern.

 

I am all about making things, but you guys are aware that Scarebird has these brackets available, pretty cheap, right?

 

I do believe I did. I did this as a budget deal. Are those brackets for Explorer? The ones I found were for 1990 Celebrity. Most of the brackets and kits I found required some machining or bending of the steering brackets and also used parts from a 78 ish Volare. Since my local Parts stores dont carry those on the shelf I opted to create something that allow me to walk into any parts house and get what I needed right off the shelf. I did this because (although I sold my car) I was driving it every day. Just like any other daily driver its nice to be able to get the part right now. The Explorer is also a dual caliper.

I was also getting ready to put a disk brake rear end in from the same vintage Explorer since the width is almost perfect for the swap. That combo would allow me to easily get parts for some time since the parts were used from 96 to 2001.

 

Hi.. How are the wheel Studs held in place? were the holes oversized for the stud teeth? did you tack weld at the back? to keep the studs from turning?

Thanks..

 

I drilled the holes in the hub to the appropriate size and pulled half inch studs through. They were held in place by the knurled part of the stud. I did that in a previous fix to get rid of the wheel bolts so I could use the mag wheels.
If you drill the holes the correct size you pull the studs through like you would any newer car and they stay in place because of the expanded part of the shouldered area of the stud.

 

wow this is awesome! thanks for your research, i want to do this to my 48.

 

I know your rotor was a little different than mine since yours was factory but I can't get it to sit all the way down even after turning down the outside of the hub to get it to pass the rotor hat. When I flipped the rotor upside down and slid it on I noticed I can't get it to go the last 1/16". I noticed this little lip at the bottom of the hub is not allowing the rotor to go all the way down. I was wondering if you had to deal with that? I could be wrong maybe it will go all they way down when everything is torqued down with the wheels on it? It just seems like it will have some play it it like it is.

 

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Ray

 

Hi. On one of them I ground it down (Carefully) thinking I needed to. My rotors had a bevel in the back side so it actually cleared without issue. A good file will take that bevel down if you take a little time. If you just put it on and torque it then you will put undue stress on the assembly. It should only take a few minutes on each to take that lip down if you need to.
Hope that helps.

 

Thats probably what I'll do I can get in there with a file, and or a small flap wheel.

 

I have a 50. Is there a tapered wheel bearing cinversion or do I have to stay with the balls? Also contact me at [email protected] would purchase template if necessary. Also info on rack and pinuin steering. Been at this hot rodding since the sixties. We need to teach our children. Thanjs Jim B

 

Here is a link to the page with the scan of the template. Problem is that I think your spindles are different. Check before you go through all that work. Print out the template and cut it out. You can measure out the hole spacing etc. and see if it will work. The template is in PDF format and should print out actual size. I scanned it with a graph paper background. The info is on the page. http://car.icompute.info/disk_bake_bracket.htm