onlyinajeep726 Posted June 14, 2013 Share Posted June 14, 2013 Ok guys, I'm sure this topic gets beaten to death about as much as Cherokee doors on an MJ does, but I couldn't find specifics for an '86. Anyway, I know that I will need either a '95-'96 XJ booster or a WJ booster and their respective MC's. What I need to know is will either of those be a bolt in affair for my '86 MJ? I've done the '95-'96 XJ booster swap on my '88 XJ with much success. I just want to be certain of it for my MJ. I should also mention that am going to be setting the brake system up like the XJs, ridding me of that level-sensing rear prop valve that is known to fail. I don't even have the linkage that connects the MJ prop valve to the rear axle, so it's just hanging there all willy-nilly. What all will I have to do to make all of this happen? Drop some knowledge on me CC! Thanks to all who can help! Link to comment Share on other sites More sharing options...
skidoo_j Posted June 14, 2013 Share Posted June 14, 2013 the 86 and 88 should be the same. The year it got more streamline is 91 or 92. In those years you didnt have to bore the hole in the push rod and grind the flat spot for the switch. You may need to make a spacer for between the firewall and booster if you want your pedals level. If you acquire the pedal and the brake switch it eliminates the need to do the grinding/ drilling. Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 14, 2013 Author Share Posted June 14, 2013 Ok, that's what I needed to know. I figured it would be the same. Time to hit up the junkyard. Link to comment Share on other sites More sharing options...
GirsMJ86 Posted June 14, 2013 Share Posted June 14, 2013 Are you going to also be swapping in the XJ valve and ditching the MJ prop valve on the rear axle? If so a write up with pics along the way would be awesome since the only one I could find in the DIY section involves the WJ BB/MC and didn't mention the prop valve. Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 14, 2013 Author Share Posted June 14, 2013 Sure, I can post a write up. What I plan to do is utilize one of the lines that runs to the rear already, disconnect it from the level sensing device, and replace the distribution block up front with an XJ block/prop. The main reason I'm doing all this now is because I've discovered that I have a leaking wheel cylinder in the rear and I by no means feel like going through the 25 step process of bleeding the brakes because of something that I can't even use. I plan to do the ZJ rear discs at a later time anyway, so this is all kind of preemptive. Link to comment Share on other sites More sharing options...
1989 Eliminator Posted June 18, 2013 Share Posted June 18, 2013 So I am also thinking about replacing my 89' MJ brake booster with a dual diaphram one. Would a 95'-96' XJ brake booster work for me? Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 19, 2013 Author Share Posted June 19, 2013 Yes. However, with that said, it will need modification to work correctly and you'll need the master cylinder that goes with it. http://naxja.org/forum/showthread.php?t=924285 http://www.jpmagazine.com/techarticles/drivetrain/154_0810_cheap_jeep_brake_system_upgrades/ http://www.cherokeeforum.com/f51/xj-brake-upgrade-3352/ http://www.4x4wire.com/jeep/tech/brakes/xj_wjbrakes03/booster/ Link to comment Share on other sites More sharing options...
Echostrike Posted June 19, 2013 Share Posted June 19, 2013 Hey does the dual diaphram booster you are using interfere with the clutch master cylinder? I see you have an AX-4, I myself have an AX-5. I would love to do this swap (as my booster is kaput) but I can only find ppl that have done the switch in an auto trans. Thanks. Link to comment Share on other sites More sharing options...
airspeed Posted June 19, 2013 Share Posted June 19, 2013 The clutch MC will clear just fine. http://comancheclub.com/topic/36911-96-brake-booster/?do=findComment&comment=370358 Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 19, 2013 Author Share Posted June 19, 2013 Yes, the clutch MC has plenty of room. The WJ booster is no bigger around than the stock booster, it only sticks out further from the firewall. The only problem I'm having at the moment with this upgrade is that the main line running to the rear is leaking around the compression nut on the proportion valve. However, that is as a result of a bad flaring job on my part I believe. I used an XJ prop. valve and ran a traditional braking system, bypassing the load sensing rear valve. My issue will likely be resolved by reflaring that line. Link to comment Share on other sites More sharing options...
martin809 Posted June 25, 2013 Share Posted June 25, 2013 I have a 92 Comanche. Do I understand this correctly. I DO NOT have to grind down the rod to do this upgrade. I can take any dual diaphram and MC from a 1999 Wj and it will work. Direct bolt on? Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 25, 2013 Author Share Posted June 25, 2013 I have a 92 Comanche. Do I understand this correctly. I DO NOT have to grind down the rod to do this upgrade. I can take any dual diaphram and MC from a 1999 Wj and it will work. Direct bolt on? On a '92, I'd say that's correct. But I'll let these other guys chime in. I have done this upgrade on my '88 XJ and '86 MJ. Both Renix with that oddly designed brake light switch. Link to comment Share on other sites More sharing options...
skidoo_j Posted June 25, 2013 Share Posted June 25, 2013 I have a 92 Comanche. Do I understand this correctly. I DO NOT have to grind down the rod to do this upgrade. I can take any dual diaphram and MC from a 1999 Wj and it will work. Direct bolt on? On a 91/92 use a 95/96 dual from an xj. It's a direct bolt on, or as close to direct bolt on as possible. Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 25, 2013 Share Posted June 25, 2013 I have a 92 Comanche. Do I understand this correctly. I DO NOT have to grind down the rod to do this upgrade. I can take any dual diaphram and MC from a 1999 Wj and it will work. Direct bolt on? As said before, the best (easiest) option for the 91-92 MJs is the 95-96 dual diaphragm booster and master. It's bolt-on, provided you use the the 1/4" spacer between the booster and the firewall as the 95 and 96 XJs do. The stock brake switch is retained. You do need to bend new brake lines (I used the original fittings) from the M/C to the existing distribution block, and move your windshield washer reservoir forward about an inch, unless you move the washer tank inside the fender well as I did, another good upgrade. All in all maybe 2-3 hours including bleeding and well worth doing. Link to comment Share on other sites More sharing options...
zackcj7 Posted June 25, 2013 Share Posted June 25, 2013 So could you swap a 91-92 pedal assembly and switch into a 86-90 and do away with the early switch assembly? Seems like that might be easier than drilling out and grinding flat the newer master cylinder assembly's rod. Link to comment Share on other sites More sharing options...
skidoo_j Posted June 25, 2013 Share Posted June 25, 2013 So could you swap a 91-92 pedal assembly and switch into a 86-90 and do away with the early switch assembly? Seems like that might be easier than drilling out and grinding flat the newer master cylinder assembly's rod. Very plausible, you could pull it from the 95. You will need the switch too. so you'd have to splice wires to the new switch plug. Link to comment Share on other sites More sharing options...
zackcj7 Posted June 25, 2013 Share Posted June 25, 2013 There a '95 XJ at my local PullaPart maybe i'll have time to go by there this weekend. Hopefully the master and booster are still on it. There are 2 '97s and a '98 at the yard are those boosters different? Link to comment Share on other sites More sharing options...
skidoo_j Posted June 25, 2013 Share Posted June 25, 2013 There a '95 XJ at my local PullaPart maybe i'll have time to go by there this weekend. Hopefully the master and booster are still on it. There are 2 '97s and a '98 at the yard are those boosters different? It's the same master cyclinder. The booster on the 97 has a push rod that is a lot longer. It's the same unit, but different push rod. It could be made to work by cutting/welding or rebuild???. So it's not worth getting the booster from the 97 you could get the master off the 97 if the 95 is missing the master but has the booster bottom line. Get the 95/ 96 Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted June 25, 2013 Author Share Posted June 25, 2013 I feel like it would be more work trying to get the '95/'96 brake pedal assembly unbolted and put into a Renix era, but maybe that's just me. I've had success with drilling and grinding a flat spot. Also, as mentioned above, stay away from '97 - '01 XJ boosters if you have a choice. I wouldn't trust a cut and weld job on the booster rod. Not going to take that chance when I have other viable options. WJ booster gives a little bit more braking power over the mentioned XJ ones, but both are a huge improvement over our stock ones. Link to comment Share on other sites More sharing options...
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