Boost and MC Options

[EUREKA]

6 hours ago, ghetdjc320 said:

Let’s clarify a few things here. The kit that fits 90/91+ d44/d35 and 8.25 will NOT bolt on to original XJ/MJ D44s. It can be modified to fit but it’s basically just a set of d35 ZJ backing plates with Exploder or ZJ rotors. Treadles does make a kit that is supposed to be bolt on for earlier model D35’s and D44s. Non c-clip d35s (89 and earlier) and XJ and MJ D44’s have the same mounting flange pattern. TJ d44’s and 90+ D35s as well as 8.25’s share the same flange pattern. The ZJ backing plate has to be slightly enlarged for the tj d44 and the xj 8.25. Easily done with a dremel. Also as @Garvin mentioned, you’ll need a press and might as well replace the axle bearings and seals while your in there.

Just remember, your really not gaining any additional braking power when going to an exploder/ZJ caliper and rotor setup. I’d look into doing at least a dual piston caliper with 12” rotor for all the work it entails. The ZJ rear disk setup is an easier swap on  the newer d35/tj d44 and xj 8.25. 
Here is some info on the variations of the teraflex kit:

Thanks for that. I have come across several threads and videos that cover modifying the ZJ backing plate.

I normally take anything I need to press down the street to a 4x4 shop but I plan on buying a press from harbor freight.

I am going to rebuild the entire axle.

 

So how do I get dual piston calipers and 12” rotors on my MJ Dana 44?

[ghetdjc320]

If your up for modifying the ZJ style backing plate then consider doing the Wilwood kit linked in the brake thread. It’s made to fit the 90+ D35 just like the ZJ and comes standard with duel piston calipers and 12” rotors. You can move on up to even 6 piston calipers with that backing plate. I don’t have the part numbers for the other caliper options but there is another member here who does. I think he posted into build thread with that info. 

[EUREKA]

33 minutes ago, ghetdjc320 said:

If your up for modifying the ZJ style backing plate then consider doing the Wilwood kit linked in the brake thread. It’s made to fit the 90+ D35 just like the ZJ and comes standard with duel piston calipers and 12” rotors. You can move on up to even 6 piston calipers with that backing plate. I don’t have the part numbers for the other caliper options but there is another member here who does. I think he posted into build thread with that info. 

Sounds like that's exactly what I'm going to so. Thank you very much!

[ghetdjc320]

 That kit is listed for the 97+ TJ D35 since it uses the TJ style parking brake cables but the flange is the Chrysler 8.25/D35/TJD44. Should be a very straightforward parking brake connection from our MJ’s. You’ll probably also need that spacer for the axle bearing. 

[ghetdjc320]

https://www.wilwood.com/brakekits/brakekitaxleflange
 

This is a nice reference to the different axle flanges. 

[EUREKA]

On 9/13/2020 at 8:22 PM, ghetdjc320 said:

 If you want disks in the back but aren’t going to upgrade to a 4 piston front then go with these: https://www.shop.blackmagicbrakes.com/Dana-44-Rear-Disc-Brake-Conversion-Kit-Dana-44-Rear-Disc-Conversion.htm

Just to be clear, given that  I am planning on increasing the performance of the front brakes, would you still recommend this kit for the rear?

[EUREKA]

On 9/13/2020 at 9:00 PM, ghetdjc320 said:

For your rear axle you already have 10” drums that are quite decent if your in a time pinch. Do the wj or xj swap then and if you have a good functional real valve you can keep that setup or remove that system and run an xj prop valve or an adjustable Wilwood one. In my build thread I documented the swap a few weeks ago

The thing is I will already be installing a Detroit Truetrack in the rear and repainting it and all (maybe changing the gear ratio, I haven't decided on that yet). It just feels like the right time to switch the rear to disk. I'll make time.

[EUREKA]

So to sum things up a bit I'm thinking;

 

95-96 XJ Booster and MC (will this bore be a good match for the kits below?)

will require;

1. a 1/4" spacer between the booster and firewall
2. modification of the end of the booster rod to fit the brake switch.
3. Bending new lines from the new 95/96 master to my existing combo using the existing combo valve flare fittings on new lines.

For the rear brakes (MJ Dana44 axle)

This kit from Black Magic Brakes, Dana-44-Rear-Disc-Brake-Conversion-Kit

(will require slight modification of the backing plates to match MJ Dana 44 backing plate?)

 

For the front brakes (MJ Dana30 axle)

The steering knuckles from my 88 MJ

This kit, Wilwood Forged Narrow Superlite 4R Big Brake Front Brake Kit

 

[ghetdjc320]

54 minutes ago, EUREKA said:

Just to be clear, given that  I am planning on increasing the performance of the front brakes, would you still recommend this kit for the rear?

Well it’s a bolt on kit and gives the advantage of disks. No real stopping power improvements over well functioning drums though. I would do it for the convenience though. The front takes most of the braking load and is where I would invest first if I had to choose just one though. If you switch to rear disks I’d recommend running a new line to the rear and just removing the load sending valve and old distribution block. Install a Wilwood adjustable prop valve with passenger side drop bracket. That way you can dial in your brakes and make adjustments for future updates. Just my $.02 

[EUREKA]

14 minutes ago, ghetdjc320 said:

Well it’s a bolt on kit and gives the advantage of disks. No real stopping power improvements over well functioning drums though. I would do it for the convenience though. The front takes most of the braking load and is where I would invest first if I had to choose just one though. If you switch to rear disks I’d recommend running a new line to the rear and just removing the load sending valve and old distribution block. Install a Wilwood adjustable prop valve with passenger side drop bracket. That way you can dial in your brakes and make adjustments for future updates. Just my $.02 

I understand, the drums probably have superior stopping power, but not once they are hot. And there are the other advantages of disks.
I don't have to choose between upgrading the front or rear system, I want to do both.

Is it not worth making the adjustable rod for the load sensing valve?

If I delete the load sensing valve, do I remove one of the lines going to the rear and plug the port on the combo valve (or join them with a tee) ?

What is a passenger side drop bracket?

 

 

[ghetdjc320]

30 minutes ago, EUREKA said:

I understand, the drums probably have superior stopping power, but not once they are hot. And there are the other advantages of disks.
I don't have to choose between upgrading the front or rear system, I want to do both.

Is it not worth making the adjustable rod for the load sensing valve?

If I delete the load sensing valve, do I remove one of the lines going to the rear and plug the port on the combo valve (or join them with a tee) ?

What is a passenger side drop bracket?

 

 

If you go to rear disks then the adjusting valve isn’t going to give the correct pressure for disks. Remove the load sensing valve and delete the distribution block. Run a new copper line back to the soft axle line. Replace the distribution block with and adjustable valve (eg wilwood) and the bracket that mounts to the MC studs in the booster and provided a solid mount for the prop valve. You need a passenger side drop bracket since there is no room for the prop valve to be in the drivers side of the MC without removing the washer bottle (or updating to the 97+ bottle). The pic of the bracket and mounting is in my build thread. Alternatively, you could use a ZJ prop valve. The distribution of pressure for disks is pretty close to 50/50. You will likely want less than 50% in the rear though depending on whether or not the truck has anything in the bed. Difference in front and rear piston sizes in the calipers makes a difference as well. An adjustable valve makes it easy to adjust properly.

[JustEmptyEveryPocket]

6 hours ago, ghetdjc320 said:

If you go to rear disks then the adjusting valve isn’t going to give the correct pressure for disks. Remove the load sensing valve and delete the distribution block. Run a new copper line back to the soft axle line. Replace the distribution block with and adjustable valve (eg wilwood) and the bracket that mounts to the MC studs in the booster and provided a solid mount for the prop valve. You need a passenger side drop bracket since there is no room for the prop valve to be in the drivers side of the MC without removing the washer bottle (or updating to the 97+ bottle).

This is the route I went. Its not that hard, and I feel better knowing all my brake lines are NiCop with gravel guard. While I used the wilwood prop valve I wanted it mounted driver side of the booster. So I made my own bracket (kind of a 45* thing... I can take a pic if you want) and moved the washer bottle to the fender. I had been meaning to do that anyways. 

 

Now for the outcome: Based on people's experience with swapping in a WJ booster I had high expectations. Obviously my brakes were better than when I started, but that was because of a blown line . To me the pedal feel was exactly the same as before, and I could slow down exactly the same as before I blew out a line.  Since then I realized that as soon as you have enough power to lock up the tires, bigger and better brakes won't help at all. So IMHO I would run new lines, maybe do a WJ (95/96XJ) booster, wilwood prop valve, rear disks and thats it. Anything else is just a waste of money.

 

Good luck 

[EUREKA]

38 minutes ago, JustEmptyEveryPocket said:

This is the route I went. Its not that hard, and I feel better knowing all my brake lines are NiCop with gravel guard. While I used the wilwood prop valve I wanted it mounted driver side of the booster. So I made my own bracket (kind of a 45* thing... I can take a pic if you want) and moved the washer bottle to the fender. I had been meaning to do that anyways. 

 

Now for the outcome: Based on people's experience with swapping in a WJ booster I had high expectations. Obviously my brakes were better than when I started, but that was because of a blown line . To me the pedal feel was exactly the same as before, and I could slow down exactly the same as before I blew out a line.  Since then I realized that as soon as you have enough power to lock up the tires, bigger and better brakes won't help at all. So IMHO I would run new lines, maybe do a WJ (95/96XJ) booster, wilwood prop valve, rear disks and thats it. Anything else is just a waste of money.

 

Good luck 

Do you do much driving over extremely steep grades with a load? This is when I find the brake system lacking, even with my AW4 setup so that I can make it stay in 2nd. When ambient temps are 100+ it doesn't help. I'll admit I am upgrading some aspects of this truck far beyond what I really need for the tire size I will be running and the level of off-roading it will see. This is simply to placate my obsessive compulsive nature.

[EUREKA]

6 hours ago, ghetdjc320 said:

If you go to rear disks then the adjusting valve isn’t going to give the correct pressure for disks.

Of course, I wasn't thinking clearly.

 

Is the Wilwood valve and bracket that you used part# Wilwood 260-13190

[JustEmptyEveryPocket]

I drive lots of back county roads, pasture land, mountain roads, etc. Not sure how else to quantify it, but my truck is not just a pavement princess. No rock crawling or anything along those lines though. I might be missing something in the discussion, but to my mind once you have enough braking power to lock up your tires on flat pavement then larger rotors, bigger boosters, larger calipers, etc aren't worth the $$$. They might be good for EXTREME rally tracks where you need heat dissipation and a booster that is not vacuum dependent. But I just don't see what the gain is to justify the cost in your proposed scenarios. Not saying its not there, and if I'm wrong then please educate me. Otherwise my opinion (worth exactly what you paid for it) is to put the money into other upgrades or options.

 

For me and my truck, I have way plenty of braking for everything I do. Your truck and situation may be entirely different. So at the end of the day its your rig to do with whatever you want and your wallet allows.

[EUREKA]

2 hours ago, JustEmptyEveryPocket said:

I drive lots of back county roads, pasture land, mountain roads, etc. Not sure how else to quantify it, but my truck is not just a pavement princess. No rock crawling or anything along those lines though. I might be missing something in the discussion, but to my mind once you have enough braking power to lock up your tires on flat pavement then larger rotors, bigger boosters, larger calipers, etc aren't worth the $$$. They might be good for EXTREME rally tracks where you need heat dissipation and a booster that is not vacuum dependent. But I just don't see what the gain is to justify the cost in your proposed scenarios. Not saying its not there, and if I'm wrong then please educate me. Otherwise my opinion (worth exactly what you paid for it) is to put the money into other upgrades or options.

 

For me and my truck, I have way plenty of braking for everything I do. Your truck and situation may be entirely different. So at the end of the day its your rig to do with whatever you want and your wallet allows.

I'd say what you maybe missing is that brakes become less effective with heat, and on serious grades (I understand most states don't have them) that can become an issue. Especially when ambient temps are 100+. I don't see how being able to lock up brakes on flat ground is a good test for anything but being able to lock up brakes on flat ground, and of course that has a lot to with the traction you are getting. Granted I never had the size drums that I do now with the MJ Dana 44 but the stock brake systems of other Jeep vehicles (XJ and ZJ) have certainly been inadequate for my region/use. With rotor and pad upgrades, well adjusted rear, and a otherwise perfect braking system the ZJ wasn't too bad, but once loaded with people and cargo, on many roads here it was just barely good enough, and still rotors would warp sometimes. California does have 7 of the 10 steepest roads in the US and I go over passes like Tioga pass or Sonora pass every year. My county particularity has many very steep roads which I will often travel over with significant loads.

I'm sure neither of us is all that interested in convincing the other on this issue. I'm sure we both have well over a decade of driving XJ, ZJ and MJ's in our respective regions for our respective uses. And I should say that I am aware the specific upgrades I am going with are somewhat beyond even my needs, but I like to do things that way and I'm not too satisfied with intermediate options.

 

I not too concerned with the budget on this build. I knew this job was dangerous when I took it.

[ghetdjc320]

12 minutes ago, EUREKA said:

I'd say what you maybe missing is that brakes become less effective with heat, and on serious grades (I understand most states don't have them) that can become an issue. Especially when ambient temps are 100+. I don't see how being able to lock up brakes on flat ground is a good test for anything but being able to lock up brakes on flat ground, and of course that has a lot to with the traction you are getting. Granted I never had the size drums that I do now with the MJ Dana 44 but the stock brake systems of other Jeep vehicles (XJ and ZJ) have certainly been inadequate for my region/use. With rotor and pad upgrades, well adjusted rear, and a otherwise perfect braking system the ZJ wasn't too bad, but once loaded with people and cargo, on many roads here it was just barely good enough, and still rotors would warp sometimes. California does have 7 of the 10 steepest roads in the US and I go over passes like Tioga pass or Sonora pass every year. My county particularity has many very steep roads which I will often travel over with significant loads.

I'm sure neither of us is all that interested in convincing the other on this issue. I'm sure we both have well over a decade of driving XJ, ZJ and MJ's in our respective regions for our respective uses. And I should say that I am aware the specific upgrades I am going with are somewhat beyond even my needs, but I like to do things that way and I'm not too satisfied with intermediate options.

 

I not too concerned with the budget on this build. I knew this job was dangerous when I took it.

I agree with the ZJ brakes barely being adequate. We tried to do that brake system write up to help avoid some of the issues that @JustEmptyEveryPocket experienced, namely, no real improvement over stock. Hands down the best upgrades are hydroboost and multi-piston calipers with larger disks. Every Jeep I get I invest in steering and brakes first and go from there. 

[JustEmptyEveryPocket]

@EUREKA As long as we enjoy wrenching on our vehicles and they do what we need them to right?  Just figured I would throw out my opinions. Good luck with your build.

[EUREKA]

1 hour ago, JustEmptyEveryPocket said:

@EUREKA As long as we enjoy wrenching on our vehicles and they do what we need them to right?  Just figured I would throw out my opinions. Good luck with your build.

Absolutely! Thanks I appreciate it. I've been taking pics along the way so I should probably start an actual build thread at some point.