mikekaz1 Posted September 14, 2015 Share Posted September 14, 2015 so i was looking into replacing the booster set up on my MJ. i know most say to go for a 95/96 XJ setup. but i have a parts 98ZJ already and all parts would thus be free for me... is there any difference between boosters? Link to comment Share on other sites More sharing options...
Crash Posted September 15, 2015 Share Posted September 15, 2015 If you swap booster and master together, not an issue. Link to comment Share on other sites More sharing options...
mikekaz1 Posted September 15, 2015 Author Share Posted September 15, 2015 Ya I was going to swap the whole assembly but wasn't sure if there were rod differences or something slightly unknown before tearing everything apart to fond out I can't do it. Link to comment Share on other sites More sharing options...
cruiser54 Posted September 16, 2015 Share Posted September 16, 2015 99 to 2004 WJ is the best conversion. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 16, 2015 Share Posted September 16, 2015 99 to 2004 WJ is the best conversion....... ......for the Renix I guess? Why is the WJ swap "the best"? Link to comment Share on other sites More sharing options...
cruiser54 Posted September 16, 2015 Share Posted September 16, 2015 Has nothing to do with Renix versus HO. Another boring and oft-repeated ditty from me. WJ versus 95 to 96 XJ booster Actually, the WJ booster is in some ways easier than the 95 to 96 XJ. I've done both. XJ, you don't have to mess with the firewall. No big deal anyway. But, you have to move the washer reservoir. And, once the original booster comes out, the bracket inside the cab moves and makes it a bear to install the new booster. WJ you have to bend or cut the firewall lip, but don't move the washer bottle. As an added bonus, the mounting studs of the WJ booster are a bit smaller and it's easier to get in. Another bonus with the WJ is that it has FLEXIBLE lines from the master cylinder that make putting things together MUCH easier. And, WJ boosters are newer and easier to find….. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 16, 2015 Share Posted September 16, 2015 It has everything to do with a Renix vs. an HO. On the HO MJs the 95-96 is pure PnP if you use the 1/4" spacer that comes with the booster. The 95-96 dual diaphragm booster/master was made to replace the 91-94 setup with basically no mods. No firewall massaging, the mounting studs are the same as the old booster, there is no bracket movement, no booster arm mods needed, the washer tank needs to move back about 1/2" (no problem), and the 95-96 also comes with flexible lines from the master. But I bent my own lines for better fitment. And, WJ boosters are newer and easier to find….. I guess. My real question is since you have done both mods on a Renix but not on an HO, is there any real difference in stopping power between the 95-96 and WJ setups? Link to comment Share on other sites More sharing options...
mikekaz1 Posted September 16, 2015 Author Share Posted September 16, 2015 Good info and options. But does anyone know a difference between a dual diaphragm XJ and dual ZJ? Or have length stats I can at least try and measure/compare on the ZJ. As I have a parts ZJ in my driveway already. And if its comparable or exactly the same I'd like to save the money on buying one. Link to comment Share on other sites More sharing options...
LarryH88bt Posted September 20, 2015 Share Posted September 20, 2015 I'm in the middle of this swap right now. Under the dash the automatic transmission linkage is blatantly blocking the lower left stud of the brake booster. Have no idea how to get it off. Update: I ended up disconnecting the fuse box. There's two gold phillips screws under the dash and a little 7mm bolt on the firewall side. All three have to be unfastened and the the box has to be yanked apart because it's full of that tar stuff that's also in the c101 connector. With the fuse box out, I was able to get a box end wrench around the nut. Taking out the washer bottle and the air box gives some more room to work. Link to comment Share on other sites More sharing options...
RochesterMJ Posted September 21, 2015 Share Posted September 21, 2015 Larry - I did this swap earlier this summer and I agree the toughest thing was that damn cable (brake light?) blocking the lower left bolt. The plastic sleeve can be disengaged (with significant effort) from the bracket and then wrestle the cable out of the way. The one tip I don't recall seeing is to remove the lower dash, gives straight-shot access and visibility of the bolts. Watched a couple youtube videos of guys crawling under there, I have no idea how they got the bolts out. Harbor Freight has a decent brake bleeder kit that runs off an air compressor. If you bought your parts Booster/MC from the junkyard you can get plastic adapters from Autozone that will allow you to bench bleed the MC. Link to comment Share on other sites More sharing options...
mikekaz1 Posted September 21, 2015 Author Share Posted September 21, 2015 I know I got the bolts off of the ZJ booster with a deep socket, swivel and a 1ft extention on an impact gun, and then the two lines off the ABS module. had the booster out in under 5 min. Link to comment Share on other sites More sharing options...
ScottJeep Posted September 21, 2015 Share Posted September 21, 2015 Having done this using a 96' unit on my 89' earlier this summer.... the booster arm/rod modification for the brake light switch where the biggest PITA. With average tools ( deep well, swivel, extended length extension) the getting out and back should not be big deal. Also the newer XJ units cannot be used as the booster arm/rod is significantly longer. (it looked so new... I was blinded by beauty but stupid to the obvious...luckily was able to sell on eBay.) Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 21, 2015 Share Posted September 21, 2015 it looked so new... I was blinded by beauty but stupid to the obvious... Ah yes. That's happened to all of us a couple of times........... Link to comment Share on other sites More sharing options...
LarryH88bt Posted September 22, 2015 Share Posted September 22, 2015 Doing the lines from the WJ master to the MJ prop is a head scratcher for me. I think I may just buy the M12 and the M10 lines bubble flared for the master side and then cut the other end, double flare them, and reuse the old MJ fittings on the prop side. I can't find the right size fittings on their own. The MJ prop uses like a 1/4in and a 7/16? Link to comment Share on other sites More sharing options...
cruiser54 Posted September 22, 2015 Share Posted September 22, 2015 Doing the lines from the WJ master to the MJ prop is a head scratcher for me. I think I may just buy the M12 and the M10 lines bubble flared for the master side and then cut the other end, double flare them, and reuse the old MJ fittings on the prop side. I can't find the right size fittings on their own. The MJ prop uses like a 1/4in and a 7/16? Correct. Use the fittings off your old lines...... Link to comment Share on other sites More sharing options...
The_Anvil_Grey_Comanche Posted September 24, 2015 Share Posted September 24, 2015 I have a 90 Comanche lifted on 33"s and just did a disc brake 8.8 swap. I had a 99 Cherokee parts Jeep so I grabbed the booster & MC off it. Then got a proportioning valve from a ZJ. I have never had as good of brakes as I do now! This thing will almost nose dive if I hit the brakes hard. Very good upgrade! Link to comment Share on other sites More sharing options...
LarryH88bt Posted September 27, 2015 Share Posted September 27, 2015 Got the new booster and master in. Hooking up the lines from the master to the prop was painful. I had all the right fittings, used a piece of baling wire as a mock up, bent the lines no sweat, flared them perfectly, then the suckers just wouldn't line up. Naturally. If the fitting and the line weren't perfectly aligned the fitting wouldn't thread. Hopefully the master is bled correctly because I do not want to take those lines off again. May have also shaved off a teeny bit too much from the rod. Brakes lights didn't come on but I didn't quite have everything in the right place, just checked it quick. What I'm thinking is there wasn't enough resistance on the plunger to push on the spring in the switch, the spring is pretty heavy. Now with the master bolted in and hooked up that might be the ticket. Link to comment Share on other sites More sharing options...
LarryH88bt Posted September 29, 2015 Share Posted September 29, 2015 Got it on the road, big difference. It will be even better when I get some good brake pads. Problem with the light switch still, Right now I have a couple pieces of bailing wire hooked around the switch to give it some more surface. I think I might have to tack weld a small bead to the plunger for a more perm fix. Link to comment Share on other sites More sharing options...
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