2ndgearhero
New member
TLDR: a lot of head scratching resulted in an overly complicated, yet simple driveline brake... I am happy with the results.
This write-up has been about a month in the making. I was struggling to get the Jeep ready for MM and then right afterwards get my house on the market and find a new place to live so I was balls to the wall. Now that I have some free time I can sit down and write this up.
This all began with my dream of never having to adjust drum brakes ever again. I don%u2019t know if I am just bad at it or if the whole jeep rear brake system is terrible enough that you only get about 2 weeks of good holding power out of a drum parking brake before its out of adjustment. Needless to say, I have a 5 speed and I tend to notice when I park on an incline and the parking brake doesn%u2019t have enough holding power. So the plan became, eliminate the drum rear end, then it evolved into eliminate the drum and drop in a TJ or ZJ rear brake set up to finally: Why not reinvent the wheel and put in JK front calipers with XJ front rotors for my rear brakes and then figure out the parking situation?
The first step in ditching the drum brakes was to look into the Dana 44 axle and see what rotor made sense on it. Looking at a TJ rotor was quickly ruled out because of 2 things: 1) I knew I was going to need to make a caliper bracket which means welding to the axle tube and I wanted to stay as far away from the bearing cup as possible to avoid the potential for warping and 2) At the most I wanted 1%u201D of offset in the bracket to limit the torsion the bracket would need to resist. The TJ rotor was 2%u201D too short. Looking to the front of the XJ, it has a nice deep hat for the rotor so it would extend further down the axle tube. I decided to run with that idea.
I had my rotor picked but to determine the proper caliper would be another experience. At first I was looking for a manually actuated rear disc caliper, a 1970%u2019s Cadillac rear caliper looked promising however many people complain that it just doesn%u2019t hold. So abandoning this idea I began a lengthy trip through Rock Auto looking at sizes of similar calipers which work with an XJ rotors (thickness and diameter) combing through all of the specifications pointed me to the front JK caliper. the two rotors are similar in size and the JK front caliper came with it%u2019s own mounting bracket; Meaning I did not need to fabricate a means of holding the pad assembly so that the caliper would mount to it. (look at XJ front calipers vs a JK front calipers to understand that principle).
From there it became a game of measurements; I would need to fabricate a caliper mount to accept the JK caliper and then weld it to the D44. After juggling the caliper and rotor to determine the proper bracket dimensions (taking into account the location to bleed the caliper, of course). I got in touch with a family friend who is a VERY good ornate metal worker who happens to have a cnc plasma cutter and a love for one-off projects like this. I drafted everything up and send the DXF file over to him along with the required bends
and with the help of a press brake larger than your living room,
he was able to bend 3/8%u201D plate to the specifications I had asked for. After some minor drilling, reaming and grinding Viola! A mount for a JK brake caliper.
I then ground things down for final fitment with the help of a few people to help eyeball things. I then asked a friend who is a certified welder to actually do the welds because I trust his welding ability over mine when it comes to things like brakes!
This is all an aside, but I have to applaud the efforts of my friends with what they can accomplish from my hairbrained ideas. THANK YOU!
This leads us to the need for a parking brake: I made a phone call in early April to High Angle Driveline because they offer a similar kit for a transfer case brake that I saw from another forum (jeep forum link) so I reached out to him and he informed me that the transfer case rotors would be out of stock until mid June if not July. That was not an option as I need things done before Mohawk Mayhem. I started to look into what a transfer case brake consists of: a rotor, a caliper, and a bracket which holds the 2 together. Throwing shade at the link above but, I also knew that I did not want to simply bolt a pully to the bottom of my jeep as a means of holding it for a manual parking brake, I wanted something a little more gooder.
Looking at the specifications for a professional transfer case brake it was not dissimilar to the setup on an ATV or dirt bike, so jumping on Amazon I was flush with Chinese brake rotors and calipers. The next hurdle was to figure out how to mount it. I needed to fabricate an intermediate plate to mount the rotor to the yoke of the transfer case. With the aid of CAD, a pair of dial calipers, and set of reamers, a mill drill, a lathe, a file, and patience, I developed this intermediate plate.
It fit the rotor very well but there was some misalignment when it came to the yoke of the transfer case. I decided that instead of machining the back faces of the yoke that I would install washers to get the plate (and now rotor) to mount nicely to the yoke%u2019s back face (non machined except for the counter bored areas). All said and done, I ended up with .005%u201D of runout from the face of the rotor so I will call that good.
After mounting the rotor to the transfer case, I began work on the caliper mount. I had a few old VW suspension parts laying around where the spacers fit the transfer case bolts exactly. So after cutting the spacers out of the VW control arms I was left with this (also cannibalizes from VW parts). I trued the rotor, caliper and bracket as best I could with compressed air in the caliper and ended up with this.
After putting the transfer case back in the jeep, I began to determine how to tie in the master cylinder with things.
Taking the center console out, I took to making a new bracket which would hold the new master cylinder. I fabricated a bracket to hold the master cylinder and mounted it to the airbag module mounting points as it was right in line with the parking brake lever. I took out the old brake cable and routed my hydraulic lines through. After lining everything up I welded the end of the plunger to the parking brake handle.
I only get maybe 3-4 clicks from the hand brake but she holds very well as a muddy trip to MM proved as much. As of this writing, I don't have access to the jeep (broke the track bar mount) but I will include finished photos of the install. Noticed that the airbag light has gone off and I imagine that has something to do with the fact I mounted a hand brake to the module itself so that will be the next thing to handle. Also I want to stiffen the bracket a little more and start trimming to put the center console back in... I miss having cup holders. When I went to have the 35's mounted the guy mounting the tires noticed that the caliper bracket was rubbing against the rotor, so I had to grind back the bracket where the pad ears ride to get it to clear.
So with CAD, some hand tools, scrap material, a lathe, a mill, and a wife who doesn't mind you being in the garage all night, you too can make this happen!
This write-up has been about a month in the making. I was struggling to get the Jeep ready for MM and then right afterwards get my house on the market and find a new place to live so I was balls to the wall. Now that I have some free time I can sit down and write this up.
This all began with my dream of never having to adjust drum brakes ever again. I don%u2019t know if I am just bad at it or if the whole jeep rear brake system is terrible enough that you only get about 2 weeks of good holding power out of a drum parking brake before its out of adjustment. Needless to say, I have a 5 speed and I tend to notice when I park on an incline and the parking brake doesn%u2019t have enough holding power. So the plan became, eliminate the drum rear end, then it evolved into eliminate the drum and drop in a TJ or ZJ rear brake set up to finally: Why not reinvent the wheel and put in JK front calipers with XJ front rotors for my rear brakes and then figure out the parking situation?
The first step in ditching the drum brakes was to look into the Dana 44 axle and see what rotor made sense on it. Looking at a TJ rotor was quickly ruled out because of 2 things: 1) I knew I was going to need to make a caliper bracket which means welding to the axle tube and I wanted to stay as far away from the bearing cup as possible to avoid the potential for warping and 2) At the most I wanted 1%u201D of offset in the bracket to limit the torsion the bracket would need to resist. The TJ rotor was 2%u201D too short. Looking to the front of the XJ, it has a nice deep hat for the rotor so it would extend further down the axle tube. I decided to run with that idea.
I had my rotor picked but to determine the proper caliper would be another experience. At first I was looking for a manually actuated rear disc caliper, a 1970%u2019s Cadillac rear caliper looked promising however many people complain that it just doesn%u2019t hold. So abandoning this idea I began a lengthy trip through Rock Auto looking at sizes of similar calipers which work with an XJ rotors (thickness and diameter) combing through all of the specifications pointed me to the front JK caliper. the two rotors are similar in size and the JK front caliper came with it%u2019s own mounting bracket; Meaning I did not need to fabricate a means of holding the pad assembly so that the caliper would mount to it. (look at XJ front calipers vs a JK front calipers to understand that principle).
From there it became a game of measurements; I would need to fabricate a caliper mount to accept the JK caliper and then weld it to the D44. After juggling the caliper and rotor to determine the proper bracket dimensions (taking into account the location to bleed the caliper, of course). I got in touch with a family friend who is a VERY good ornate metal worker who happens to have a cnc plasma cutter and a love for one-off projects like this. I drafted everything up and send the DXF file over to him along with the required bends
and with the help of a press brake larger than your living room,
he was able to bend 3/8%u201D plate to the specifications I had asked for. After some minor drilling, reaming and grinding Viola! A mount for a JK brake caliper.
I then ground things down for final fitment with the help of a few people to help eyeball things. I then asked a friend who is a certified welder to actually do the welds because I trust his welding ability over mine when it comes to things like brakes!
This is all an aside, but I have to applaud the efforts of my friends with what they can accomplish from my hairbrained ideas. THANK YOU!
This leads us to the need for a parking brake: I made a phone call in early April to High Angle Driveline because they offer a similar kit for a transfer case brake that I saw from another forum (jeep forum link) so I reached out to him and he informed me that the transfer case rotors would be out of stock until mid June if not July. That was not an option as I need things done before Mohawk Mayhem. I started to look into what a transfer case brake consists of: a rotor, a caliper, and a bracket which holds the 2 together. Throwing shade at the link above but, I also knew that I did not want to simply bolt a pully to the bottom of my jeep as a means of holding it for a manual parking brake, I wanted something a little more gooder.
Looking at the specifications for a professional transfer case brake it was not dissimilar to the setup on an ATV or dirt bike, so jumping on Amazon I was flush with Chinese brake rotors and calipers. The next hurdle was to figure out how to mount it. I needed to fabricate an intermediate plate to mount the rotor to the yoke of the transfer case. With the aid of CAD, a pair of dial calipers, and set of reamers, a mill drill, a lathe, a file, and patience, I developed this intermediate plate.
It fit the rotor very well but there was some misalignment when it came to the yoke of the transfer case. I decided that instead of machining the back faces of the yoke that I would install washers to get the plate (and now rotor) to mount nicely to the yoke%u2019s back face (non machined except for the counter bored areas). All said and done, I ended up with .005%u201D of runout from the face of the rotor so I will call that good.
After mounting the rotor to the transfer case, I began work on the caliper mount. I had a few old VW suspension parts laying around where the spacers fit the transfer case bolts exactly. So after cutting the spacers out of the VW control arms I was left with this (also cannibalizes from VW parts). I trued the rotor, caliper and bracket as best I could with compressed air in the caliper and ended up with this.
After putting the transfer case back in the jeep, I began to determine how to tie in the master cylinder with things.
Taking the center console out, I took to making a new bracket which would hold the new master cylinder. I fabricated a bracket to hold the master cylinder and mounted it to the airbag module mounting points as it was right in line with the parking brake lever. I took out the old brake cable and routed my hydraulic lines through. After lining everything up I welded the end of the plunger to the parking brake handle.
I only get maybe 3-4 clicks from the hand brake but she holds very well as a muddy trip to MM proved as much. As of this writing, I don't have access to the jeep (broke the track bar mount) but I will include finished photos of the install. Noticed that the airbag light has gone off and I imagine that has something to do with the fact I mounted a hand brake to the module itself so that will be the next thing to handle. Also I want to stiffen the bracket a little more and start trimming to put the center console back in... I miss having cup holders. When I went to have the 35's mounted the guy mounting the tires noticed that the caliper bracket was rubbing against the rotor, so I had to grind back the bracket where the pad ears ride to get it to clear.
So with CAD, some hand tools, scrap material, a lathe, a mill, and a wife who doesn't mind you being in the garage all night, you too can make this happen!
