87Chief Posted December 8, 2011 Share Posted December 8, 2011 If I did it too much wouldn't that keep it on? And i have to slide it down to make it work if that helps. Link to comment Share on other sites More sharing options...
comanche12 Posted December 8, 2011 Share Posted December 8, 2011 Nope, if too much, then it won't able come on anytime your press the brake pedal. I digroom des on mine too much :oops: but what did I do is jam the bolt nut(castle) lock pin between the rod flat edge and the switch. Now brake light is work. Try that if you did grind too much. :thumbsup: Link to comment Share on other sites More sharing options...
87Chief Posted December 9, 2011 Share Posted December 9, 2011 Ok, sweet, thanks! Link to comment Share on other sites More sharing options...
87Chief Posted December 14, 2011 Share Posted December 14, 2011 Thanks a lot! Switch is working well now. Haven't driven it yet since there were no brake lights lol Link to comment Share on other sites More sharing options...
87Chief Posted December 15, 2011 Share Posted December 15, 2011 I did the cotter pin but now when I push the pedal all the way it stops working.. What should I do? Link to comment Share on other sites More sharing options...
comanche12 Posted December 15, 2011 Share Posted December 15, 2011 Hm? Try Check fuse, any loosen bolts even the switch bolt too. Start easy as simple diagnose first as step to step Link to comment Share on other sites More sharing options...
87Chief Posted December 17, 2011 Share Posted December 17, 2011 I looked for the smallest cotter pin I had and cut it in half and then super glued it to the rod it works great now. I guess the cotter pin just moved too much before. Link to comment Share on other sites More sharing options...
txjeeptx Posted December 30, 2011 Share Posted December 30, 2011 Haven't been active round here in a while, but while I've got another pot on the burner elsewhere here, I thought I'd add some more info. I had a minor issue with the brakelight not working at times. I think I have it worked out now, but it came down to having to grind a bit more on the pushrod. As you depress the brake pedal, the switch rotates a bit, and it can reach a point where the switch goes open again. I ground a bit more off the upper part of the area that needs grinding for the switch flat. Seems to be working fine now. Truck stops like never before, this swap is a modification that ALL older XJ and MJ owners should do first before doing anything else to their truck. And, yes, never use compression fittings on high pressure hydraulics! EDIT: Still having brakelight issues, but its not with the switch, this time. Its somewhere in the harness, most likely the hacked-up mess of wires behind the fusebox. In the process of fixing that now. EDIT par II: Fixed the wiring harness, but still had a finicky brake light switch. Pulled the booster and welded some material back onto the top and bottom of the flat I ground in it during the inital conversion setup, then ground it all to the same flat. The switch is much happier with a larger flat area than what you can get by just grinding, since the flat for the switch now has a shape more akin to the factory pushrod. Brakelights finally work when they're supposed to. Link to comment Share on other sites More sharing options...
cody4359 Posted January 7, 2012 Share Posted January 7, 2012 This is the only booster swap I've done. I can't speak for the the 95'-96' XJ/ZJ boosters, but from what I've researched, the WJ boosters offer slightly better braking power. However, the later XJ boosters are also an easier install. Having owned 3x 96 XJs, I can say that now my MJ with 35s stops almost as well as a stock 96 XJ. How do you rate the stopping power compared to the older MJ/XJ boosters? I have to give mad props to you my Jeepin friend for all the work you've put on here....would you recommend the 95-96 XJ boosters over the WJ? Just wondering? 97-98 zj MC/Booster the same as 95-96 xj/zj? Link to comment Share on other sites More sharing options...
xjrev10 Posted March 20, 2012 Share Posted March 20, 2012 Picking up a master/booster out of a 01 tomorrow! Now only if I could find a Liberty to do disks on my 8.25... Link to comment Share on other sites More sharing options...
86ComancheXNate Posted March 20, 2012 Share Posted March 20, 2012 Is this swap better than buying a new OEM or better booster/master cylinder combo? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 20, 2012 Share Posted March 20, 2012 yes. the dual diaphragm is far superior to the factory single diaphragm setup. added assistance in braking power means you don't have to exert as much force on the pedal to get the desired braking effect....and no, it doesn't make such a drastic difference that light pressure means immediate lockup. just is a better aide for braking power, with better pressure proportioning in the master itself. only down-side...common reservoir means that if you have a leak in one brake, you lose all brakes eventually, as opposed to at least having seperate front and rear brakes with the old style master. Link to comment Share on other sites More sharing options...
carnuck Posted June 7, 2012 Share Posted June 7, 2012 Just a little nit, but do not EVER use this type of compression fitting on brake lines! Aside from being illegal, they are unsafe and panic stops cause them to blow apart plus vibes make them leak. ONLY use flared not compression fittings! Link to comment Share on other sites More sharing options...
LarryH88bt Posted June 25, 2012 Share Posted June 25, 2012 Is it necessary to change out the front prop valve to the XJ/ZJ? Or can the original MJ stay in place? Link to comment Share on other sites More sharing options...
shawn Posted June 25, 2012 Share Posted June 25, 2012 Is it necessary to change out the front prop valve to the XJ/ZJ? Or can the original MJ stay in place? most of that info is here: viewtopic.php?f=2&t=4968 - although the pictures that accompanied it seem to be now missing from wherever they were hosted :( Link to comment Share on other sites More sharing options...
ftpiercecracker1 Posted October 9, 2012 Share Posted October 9, 2012 I know this thread has pretty much run its course, but i have recently happened upon some pertanent information that might be important for the next person to attempt this upgrade. I have just recently bought a 99 wj BB, MC, and full lines. When i got them home i tried to flare the WJ lines so that they would work with the MJ fittings, no worky. Every time it would just tear the flare, it wasnt until 3 tries and 3 tears later that i realized that the MJ and WJ brake lines were of two different sizes. On MY comanche the brake lines are nearly the diameter of a pencil, where the WJ lines are about half that. Sooo what to do? I went back to the junkyard and searched every. single. jeep. They ALL had the same diameter brake line, the smaller one that is. 89-00 WJ, XJ, ZJ 4wd, 2wd all of em, not a single one had brake lines as big as mine. FWIW mine are exactly the same as the ones in this writeup. Even with this road block I was able to make it work all the same. While still at the junkyard I went back to the 89 XJ and pulled 1 of each of the fittings, as it turns out these were exactly the same as the fitting on the comanche, just drilled out for the smaller diameter brake line. Once i got the "new" fittings home it was just a simple matter of cutting off the bad flares, sliding on the fittings to the appropriate line and reflaring. Since my truck is in a thousand pieces right now i will not be able to test its functionality, but i am about 98% certain all will be well. Point of this rant, CHECK THE DIAMETER OF YOUR BRAKE LINES! hope this helps somebody :cheers: Link to comment Share on other sites More sharing options...
tmanhollister Posted November 15, 2012 Share Posted November 15, 2012 I need to do this soon, so i want to get this right. this is concerning the 96 cherokee swap, not concerning the zj-wj swap as it seems the xj swap is much easier with similar results. this will be on my 91 mj. I can get a booster/mc set up from a 96 cherokee, and it will bolt right in, no modification? *are the mc output holes on the correct side, or will new lines need to be made? *has anyone blown out their load sensing valve by adding the extra pressure or had issues with the rears locking up even with the valve,(where should the valve be set for correct operation) I will be buying new parts, which through vatozone is going to come to ~120. not bad for a preventative measure replacement/big upgrade. Link to comment Share on other sites More sharing options...
skidoo_j Posted November 15, 2012 Share Posted November 15, 2012 I need to do this soon, so i want to get this right. this is concerning the 96 cherokee swap, not concerning the zj-wj swap as it seems the xj swap is much easier with similar results. this will be on my 91 mj. I can get a booster/mc set up from a 96 cherokee, and it will bolt right in, no modification? *are the mc output holes on the correct side, or will new lines need to be made? *has anyone blown out their load sensing valve by adding the extra pressure or had issues with the rears locking up even with the valve,(where should the valve be set for correct operation) I will be buying new parts, which through vatozone is going to come to ~120. not bad for a preventative measure replacement/big upgrade. Yes if you have a '91 the 95/6 dual from a cherokee is pretty much a direct swap. The lines will have to be bent to get to the new mc, so I'd replace them. And people have blown out their load sensing valve with stock pressure, so it really depends on if you think and trust a 22 year old valve that you can't rebuild or replace. Several have replaced it with a manually adjustable valve. Willwood, sbc etc. Link to comment Share on other sites More sharing options...
tmanhollister Posted November 15, 2012 Share Posted November 15, 2012 Yes if you have a '91 the 95/6 dual from a cherokee is pretty much a direct swap. The lines will have to be bent to get to the new mc, so I'd replace them. And people have blown out their load sensing valve with stock pressure, so it really depends on if you think and trust a 22 year old valve that you can't rebuild or replace. Several have replaced it with a manually adjustable valve. Willwood, sbc etc. thanks for the clarification. Link to comment Share on other sites More sharing options...
1989 Eliminator Posted June 28, 2013 Share Posted June 28, 2013 I'm doing the same as above.... but don't you have to grind the rod for the brake switch still? besides that it should be a bolt on correct? I have an 89' MJ... Link to comment Share on other sites More sharing options...
1989 Eliminator Posted July 5, 2013 Share Posted July 5, 2013 Can I use my 89 MJ master cylinder with a new 96 Cherokee brake booster? Link to comment Share on other sites More sharing options...
skidoo_j Posted July 6, 2013 Share Posted July 6, 2013 Can I use my 89 MJ master cylinder with a new 96 Cherokee brake booster? No, the push rods for the masters are different lengths and the ends are different too. You can see the difference if you go to like autozone.com and search both years and look at the brake masters. Link to comment Share on other sites More sharing options...
1989 Eliminator Posted July 6, 2013 Share Posted July 6, 2013 I will have to ground down the rod on the 96 booster correct? when searching for the 96 booster I seen the picture and it had that flat spot on it like the MJ does Link to comment Share on other sites More sharing options...
randomguy310 Posted July 6, 2013 Share Posted July 6, 2013 will a 2000 xj a good m/c to use? what do you need from the donor xj? Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted July 6, 2013 Share Posted July 6, 2013 Yes, it will work for all MJs. What we really need is input from someone who has done the swap with later XJ boosters and the WJ booster on an MJ or early XJ to receive balanced feedback and can accurately compare the two. I believe the consensus is that the WJ booster is a technical upgrade, whether the difference in braking power is noticeable or not. The 95-96 XJ booster may work just as well. If your running larger tires than stock, I think you'd be better off with the WJ booster. But if you've got an available 95-96 XJ (or ZJ) booster then go for it. I know this was posted well over 2.5 years ago, but I can add some helpful info for both. I did the upgrade on my '88 XJ using a booster and MC combo from a '96 XJ. Did everything just like the tutorials and write up showed. Excellent upgrade for sure. Paired with ZJ rear disc brakes, my 31's can lock up if I need them to. Did the WJ booster and MC on my '86 MJ. Used an XJ proportion valve and changed it over to a standard brake system, removing the load sensing valve. Running stock 225 size tires... Definitely a good upgrade as well. All in all, both were bolt in and required the same amount of work to get them functional. As far as braking improvements goes, both seem about the same, but definitely twice as good as the stock single diaphragm setup. I haven't had the chance to drive my MJ with the WJ booster very much, but can say this for sure: I'd recommend this upgrade to any Jeeper with the crappy factory setup. Link to comment Share on other sites More sharing options...
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