Eagle

You've bumped an old thread. You would be best to post the specs of your MJ. The chances are that it will share driveline components with a like model XJ, and that will be the easiest way to get the needed parts to do a 4wd conversion. ^^^ In fact, thisa thread is three YEARS old. You'll get much better information if you start a new discussion with your question, and include some information about your truck.

Video doesn't play for me. What's it supposed to show?

Dino has been the "go to guy" for stroker info for at least ten years, probably closer to fifteen. It's virtually impossible to cover everything you need to know in one post or one thread. You get into permutations and combinations, such as do you use stock pistons with 258 rods, or do you use custom pistons with 4.0L rods? Do you deck the head or not? Do you enlarge the combustion chambers to correct for compression? Do you worry about quench height or not? And that's just for starters. My advice to anyone contemplating building a stroker is to allow at least six months (yes, I said "months") for research and study before even starting to firm up your plans.

Don't remember. Your lug nuts are 1/2" fine thread. See if a lug nut goes one. I woke up to snow on the ground this morning, so I won't be crawling under any Jeeps for a few more days. "Global warming" -- HAH!

Looking at Hornbrod's diagram, I forgot that the Renix fan used a fusible link. That's the wire that supplies power to the fan (not to the control/switch side of the relay). You are testing with the ignition in the RUN position, right? Do you have 12 volts on that red wire coming into the relay (terminal 30)? And I see I was wrong about the diode ...

I'm glad someone was finally able to get you the right part. I'm a bit surprised about NAPA, though. I thought NAPA bearings and such were made by Moog.

So you attached to the underside of the MJ frame rails rather than to the sides? About how much did you have to stretch the hitch?

The older fans supposedly only draw around 20 amps, so a 30-amp relay should be plenty. If you're buying a new one, though, why not go for the 40? FWIW, the fuse for the aux fan on my late wife's 2000 XJ is a 40-amp maxi-fuse.

I think you misunderstood. There is already a relay for the aux fan on the Renix XJs and MJs. I'm pretty sure there is no diode. The photo is my '88 XJ. On the inside of the fender, just behind (above, in the photo) the coolant catch bottle, there's a relay. That's the relay for the aux fan. That's the relay I had to cut out and replace in the '88 MJ. You probably don't have a catch bottle there. I added that when I dumped the factory plastic coolant bottle and converted to a Moroso aluminum surge tank.

Let's keep it very simple. First, ignore the discussions above, since they pertain to the '91 and '92 HO models. Hornbrod mentioned somewhere in there that the Renix aux fan is controlled differently. That's key information. That sensor that was supposed to thread into the tank of your radiator is nothing more than an ON-OFF switch. Below the preset temperature, the switch is open (off). When the coolant temperature in the tank reaches the preset limit, the switch closes and activates the relay, which in turn activates the fan. Since you no longer have the bung in the radiator, you don't need to maintain that sensor/switch. Don't throw it away, but remove it and set it aside. Go to Auto Zone or Advance or NAPA and buy a new connector that matches the one on that radiator sensor. Attach wires to it, plug it into the harness where you removed the radiator tank sensor, then run the two wires to a toggle switch in your cab. It doesn't matter which way you connect the wires to the toggle switch -- it's all the 12-volt power to the control ("trigger") side of the relay. Done. I got male connector that matches the female connector to the fan switch, attached new wires and ran them to a toggle switch. When I pluged the connector into the harness and flipped the toggle switch nothing happened, the fan would not come on. I thought maybe it was the fan motor but was able to jump it and it ran just fine. I recall that the fan should kick on when the A/C is turned on, when I moved the climate control knob to max A/C the fan never came on. Would these two things be tied together? Yes, they would. Check to see if you're getting 12 volts to the fan circuit side of the fan relay. When I bought my '88 MJ the aux fan didn't work at all -- which I didn't know until it overheated in stop-and-go traffic on a hot summer day. When I pulled the relay to check it -- two of the terminals broke off. There was so much corrosion that the relay was junk and the relay socket couldn't be salvaged. I cut the wires off the socket and wired individual terminals to each wire (didn't have a source for a replacement socket), plugged them all in, and it worked fine.

For what it's worth, Quadratec shows three hubs: 84-89 == 53000228 99-99 (w/ 2-piece stamped rotor) == 53007449 99-01 (1-piece cast rotor) == 53007449AC As a last resort, the 84-89 hubs are rebuildable. Quadratec used to see the bearings and seals as a kit -- I don't see it on their web site, but they may still have it.

Which is different? Did you take one of your rotors to NAPA to see if it will fit over their hubs? What do you mean by "their hubs will not fit inside their rotors"? My understanding has been that the differences are in the depth, or offset -- not the diameter. Somewhere I remember seeing a photo of two XJ hubs sitting on a table or a board, flange side down, and the difference in overall height was about a quarter of an inch or more.. I've never heard of a difference in diameter. What's the outside diameter of your hubs?

Well, at least I'm consistent ...

This doesn't make sense. First (although the aux fan in the HOs seems to be an exception), the ground side normally isn't switched. Switches usually go on the "hot" (supply) side. Why/how would BOTH sides of a simple circuit be grounded, and why would they both be grounded only when the key is turned on? How did you determine that both legs of 85 & 86 are grounded? Did you find that they are also both grounded with the ignition off?

See the second bullet in my post above. '89 should be generation 1 -- IF it's still an '89 axle.

Are you the original owner? How certain are you that the front axle is the original? A few years ago I bought a pretty decent-looking 2001 XJ, used. It was all stock -- no lift, no big tires, no aftermarket wheels. It had 83,000 miles on it when I bought it. Started working on fixing up things it needed (like shocks and tie rod ends). Got underneath and found yellow grease crayon numbers on the front axle. Yep -- junkyard replacement. Most people (and many shops) aren't aware that the whole brake/hub setup changed from 1989 to 1990, so they'll toss any axle they can get under a vehicle that needs an axle.

Let's keep it very simple. First, ignore the discussions above, since they pertain to the '91 and '92 HO models. Hornbrod mentioned somewhere in there that the Renix aux fan is controlled differently. That's key information. That sensor that was supposed to thread into the tank of your radiator is nothing more than an ON-OFF switch. Below the preset temperature, the switch is open (off). When the coolant temperature in the tank reaches the preset limit, the switch closes and activates the relay, which in turn activates the fan. Since you no longer have the bung in the radiator, you don't need to maintain that sensor/switch. Don't throw it away, but remove it and set it aside. Go to Auto Zone or Advance or NAPA and buy a new connector that matches the one on that radiator sensor. Attach wires to it, plug it into the harness where you removed the radiator tank sensor, then run the two wires to a toggle switch in your cab. It doesn't matter which way you connect the wires to the toggle switch -- it's all the 12-volt power to the control ("trigger") side of the relay. Done.

From my unpublished manuscript: In general, the parts to be concerned with in keeping the front brakes compatible are the steering knuckles, the hub/bearing assemblies, the rotors, and the calipers. (There is a more complete enumeration of the interrelationship of these parts in Chapter 6, Axles.) • Only two steering knuckle designs were used: 1984 through 1989, and 1990 through 2001. Left and right side knuckles are different part numbers within each group. • Three different hub/bearing units were used. The hub/bearing units are the same for both sides of the vehicle. The different years for hub/bearing assemblies were: 1984 through 1989; 1990 through mid-1999 (composite rotors); and late-1999 through 2001 (cast rotors). • Three rotor types were used: 1984 through 1989; 1990 through mid-1999 (composite); and late-1999 through 2001 (cast). • Only two caliper types were used: 1984 through 1989, and 1990 through 2001. Left and right side calipers are different part numbers within each group. The above is copyrighted and I am NOT granting permission to anyone to post it or disseminate it.

A friend cut the driver's floor out of the wreck of an '89 XJ I had here and used it to repair his '87 MJ. IIRC he had to fab a copy of the raised rib in the MJ because his was so far gone -- and the XJs don't have that piece.

That's pretty neat. Anybody happen to notice the setup on the load-sensing proportioning valve in that first photo? I suspect that truck has no rear brakes ...

I much prefer Marvel Mystery Oil rather than WD-40 for this purpose.

Are you sure some previous owner put those shock mounts on? Are you aware that XJ rear axles have the shock mounts welded to the axle tubes? Please post some photos. I think you bought an XJ axle.

It has been many years since I was at all involved in either drag racing or road racing, but my fuzzy recollection is that for leaf spring vehicles the forward fulcrum for the traction bars should be on the same line as the front spring eyes. The rear axle doesn't rotate around the front of the drive shaft, it pivots on the fixed, forward spring eyes.

I would put the brackets in a vise and clamp them closer to a kit. I'd leave maybe 1/16" of play, which would then be taken up when you torque down the through bolts. Don't forget to get everything in place and then allow the truck to sit on its tires, on the ground (or or ramps) before you torque the UCA and LCA bolts. Otherwise you'll build a preload into the bushings.

I don't know when the ZJ went to OBD2. The XJ was OBD1 through 1995. 1996 was a sort of transition year -- the '96 XJ was OBD2 because the law required it, but it was still the old body style so the OBD2 implementation was sort of a kludge. 1997 was when the entire chsassis harness was revised for a proper OBD2 implementation. So I share Hornbrod's question -- how did you make the OBD2 harness play nice with the OBD1 engine?