onlyinajeep726

Thanks a ton guys for the info!

On a random note, I will say this much... I've been on CC since January and I'm truly impressed with how helpful and knowledgeable everyone is here. Pete, Eagle, Jim, hornbrod, Automan, Geonovast, mvusse, mjeff87, mnkyboy, of course cruiser54, etc. etc. and everyone else whose name I can't recall at the moment. Y'all have never scolded me or made a mockery of the ideas and questions that I've presented. It's been a great experience. I'd recommend this forum to any MJ owner. Even recommended it to an XJ owner the other day... Lots of good info here that applies to the XJ crowd. Thanks to everyone here!

Can I see some of these pictures? :brows: I'm starting this swap and anything that I can reference will be greatly appreciated. :yes:

:agree: Maybe a sticky to it in the tech section?

Thank you a ton Eagle! :bowdown:

Ok guys, let me start off by saying that I'm swapping from a 2.5L/AX4/NP207 to a 4.0L/AX15 (external slave)/NP231 or NP242 (not sure which yet). Past few nights, I've been working on tearing out the 2.5 in my '86. I have a '90 XJ with AW4 as my donor. However, lets forget about it being an '86 for a second because I have a few general questions about the 2.5 to 4.0 swap that I haven't quite been able to find in the vastness that is the interwebz... Here goes (they'll be more as issues arise): On the AX4/5 equipped MJs, the end of the exhaust downpipe, where it stops just behind the transmission crossmember, I know that it won't work when I move the crossmember back for the AX15. My question is, can I or do I use the downpipe from the XJ donor, or will that not work either due to length? If not, what would be the best way to remedy this? Next, I know that I need to upgrade the fuel pump when going from TBI to MPI. With that also comes replacing all the rubber lines with high pressure fuel injection line. My question in regards to this is, can I reuse the steel lines that are currently under my MJ or would I/could I use the lines from the donor XJ? Also, since we're on fuel pumps for the moment, will the fuel pump and fuel level floater (fuel sender assembly I guess it's called) interchange between the XJ and MJ tank? Will there be any wiring issues or is this not a concern since they're both Renix? Now, when I get ready to remove the drivetrain, I plan to remove the engine, tranny and transfer case all in one shot. How do I remove the AX4's "stick" or shifter arm to clear the belly of the beast? My MJ sits at stock height and I have only 2.5 ton jacks to work with here. Also, will the transfer case shifter linkages work when going from the 207 to the 231/242? I also should note that I have the shifter handle, linkages and brackets from the '96 XJ that the AX15 came out of. (Don't have the transfer case though.) Forgot to add, with the added weight of the engine, will I need to grab some 4.0 coils or will the 2.5 coils suffice? On a random note, I think my AX4 is an external slave setup. I was under the impression that early AX4's were internal slaves. But, the PO did say the engine was from a later model Wrangler. Perhaps the AX4 came from the same Wrangler? Just a guess.

When I worked at a shop, the part that slid the tire on or off lifted off the rim about a quarter inch when you locked everything in place to prevent this issue.

No, the MJ and XJ blocks are double flared...

How many more threads are going to be made for this god awful thing?? My eyes just recovered from the last time I saw it... I don't know how much more of this I can take. :ack: :fs2:

I'm in Clayton, NC. You're not too far from me! I want to see pictures of this MJ.

I recently installed the IRO bolt in OTK/Crossover steering and new trac-bar, etc on my XJ. Still have play in the steering and wandering. My suspicion is the steering box is worn.

Yes, the clear cover comes off... A good cleaning is probably all it needs.

Tabs? :dunno: :hmm:

IIRC, those years used the smaller square peg for the speedo cable. If I were you, I'd look for an '88 - '90 XJ/MJ cluster.

Well, perhaps I should have added that I plan to run ZJ rear disc brake in the future and plan to change out the spring and valve in the XJ block with one from an all disc brake ZJ. Not sure if that helps or hurts my argument, but just putting that out there at least.

You can bypass the load sensing valve, but if you do, I'd run a traditional braking system and replace the MJ distribution block up front with an XJ proportion valve.

I had to beat the lip on both my XJ and my MJ. I don't have a picture at the moment of my XJ after the later XJ booster install, but here's the best picture I have of my MJ after the WJ booster install. Also, I had to move up the washer tank on my XJ, but not on my MJ... :dunno:

Yes, you'll have to drill out and grind down the rod end on the '96 booster to get it to function correctly with the MJ light switch. Technically, you can use the 2000 XJ booster, but the rod length is too long and will make the pedal sit closer to the floor. This would make a booster from these years a last resort measure. Stick with a '95/'96 XJ booster or '99-'04 WJ booster if you're going to do this upgrade. The write ups available online for this upgrade are endless and it's been done enough that you can't go wrong with the given combos. However, the master cylinder is the same part number from '95-'01 XJs so that's shouldn't be an issue.

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.

That sucks dude... I had a similar thing happen to me. I found a pristine blue '89 5-speed and 4.0L with sliding rear glass, toolbox and less than 150k miles. Emailed the guy for over a month with no response. Found out the day he sold it that he had updated his ad to include is phone number like two weeks before. Problem was, my browser didn't update cookies or some crap and his post edit never showed up. Could you imagine how pissed I was? I called him as soon as it showed up and he had sold it like 10 minutes before I called. Now I have my '86 2.5L/AX-4. Oh well... it happens I guess.

Y'know, that doesn't look half bad... Never thought a Wagomanche would look all that good.

Thanks for the link and the help guys!

Any advice or write ups on how to do a remove and install the entire dash assembly in our MJs? Mine is cracked up from 28 years of heat and sun. I am taking the dash out of an '88 XJ as it is not cracked or damaged. Wasn't sure how much work is involved or if there's anything special I need to know before starting...

I think he was referring more to the length, as that is going to matter more since the aluminum base is thicker than the plastic.

Bolts, no idea... Gasket, here you go: Rubber valve cover gasket Jeep 2.5L