Eagle

Both Pat and 87mjdriver requested that confirmation be posted when Pat made good in his commitment(s) in that transaction. I told them we would do so, either by unlocking the "other" thread, or by starting a new thread. As far as I can see, we do not have confirmation of anything yet. We also have nothing on which to justify additional bashing. Accordingly, I am going to lock this thread, too. I would appreciate it if the intended recipients would contact me, Pete, or Shelbyluvv when they have received their package(s) from Pat, so we can see that the information gets disseminated. Meanwhile, allowing further piling on strikes me as counterproductive.

If allowing the fuel pump to run until it shuts off before cranking doesn't eliminate the time lag, it obviously isn't the fuel pump. It also probably isn't the CPS, or it wouldn't start at all. I'll vote for bad spark plugs or dirty injectors.

The entire "Trail Rated" schtick is a massive marketing fraud by Jeep (started under Daimler-Chrysler). Up through the intro of the original Liberty, Jeep always proved each new model by driving it across the Rubicon Trail. They tried to do that with the Libertine, too -- in the process, they royally trashed the vehicle, and had to resort to stacking rocks at a number of the obstacles to get the Libby through at all. So they decided they wouldn't actually test new Jeeps on the trail any more. They'd just call them "Trail Rated" and call it good. I wouldn't allow one of those badges on my Jeep. Any true Jeeper will fall down laughing at you and your truck if he sees those things. They are like advertising "Hey, World. Here I am. I AM A POSEUR!"

6-bolt hubs. Jeep rims won't fit. Bad idea Remember that the Exploder 8.8 is considerably narrower than the XJ/MJ axle. If you use an 8.8 in the back, you MUST use either aftermarket rims with a lot less backspacing, or run spacers in the rear. The aftermarket rims create problems in the front, because they won't stuff inside the flares and fenders in the front. I know the 8.8 seems to have developed a following but, personally, I think a late model, 29-spline XJ Mopar 8-1/4" axle is a much smarter swap for an MJ. It's the right width, the pinion yoke is already set up for a Jeep drive shaft, and it's nearly as strong as a Dana 44. All late model 4-cylinder XJs had 4.10 gears. Should be easy to find.

Did you replace the combination/proportioning valve (the junction block beneath the master cylinder)? I don't know if the ABS-equipped model used that, but I assume they must have. And if they did, I don't know if they were the same as the non-ABS proportioning valves. The XJ proportioning valve has a spring-loaded plunger inside. It appears that plunger and the O-ring sweep/seal on the inner end of it get gummed up and don't allow much (if any) braking to the rear axle. You might try disassembling and cleaning that. It's accessed by removing the bolt-looking thing in the "nose" of the proportioning valve body. CAUTION: The spring is a strong spring. Be sure you remove the thing slowly and carefully. It'll drip brake fluid when open, so protect the painted surfaces beneath it. Many XJers simply remove the O-ring and spring, and push the plunger all the way into the "nut." This maximizes braking to the rear wheels, but disables the proportioning function. I'll be doing that on my '88 XJ very soon ... I currently have NO rear brakes. If that doesn't fix your problem, you probably need a new booster.

Cut 'em off. Dremel will work, so will a hacksaw.

I disagree. I've driven Pat's 87 on 4.10s with IIRC 31s, and for street driving it felt like too much gear. I think 3.73 would have been nicer. I'll see your disagree, and I disagree with your disagree. 3.73 gears with 31" tires is EXACTLY the same overall final drive ratio (expressed as RPMs per MPH) as stock tires and 3.54 gears. But the tires are much bigger and heavier. 3.73 is a good ratio for 30s. 4.10's is perhaps optimum for 31s and okay for 32s, anything bigger needs 4.56 or 4.88. Back to the original poster -- I would agree that 31x10.50s would be a better choice for you, and you can run them with no lift. (I'm currently running 31x10.50s on my '88 XJ, which has smaller rear wheel wells than the MJ.) However, if you MUST go to 33s, be very careful regarding width. Factory Jeep wheels have 5-1/4" backspacing. In the back, 31x10.50s end up very close to the inner fender and to the leaf springs. If you try to run tires any wider than 10.50, you will absolutely have to go to aftermarket rims that have less backspacing. "Cool," you might say. "No problem." Except that the vehicle has a front axle. In the front, 10.50 width tires on stock rims tuck up neatly inside the flares and sheet metal. Put the same tires on aftermarket rims with less backspacing, and suddenly when the suspension compresses the tires crash into the flares and sheet metal. Hilarity ensues. It's not really a good idea to go bigger on tires than what you actually need. As with lifts and pretty much everything Jeep-related, cost increases exponentially with size. The higher cost of big tires is only the beginning.

It should not be difficult to find XJs. Why get involved in mixing and matching? Buy a transmission and transfer case together and you know they work together. XJs are all over the place. The u-pull I used to go to had rows of them.

Being the resident PITA pedant, let me jump in and point out that there MAY be some lack of clarity regarding terminology here. To convert a 2WD tranny to 4WD, you would remove and replace the tailshaft. But ... note that I said tail shaft. Otherwise known as output shaft. We're not talking about just the long, tapered tailshaft housing, which is perhaps what you had in mind. The 2WD tranny has a long tailshaft and tailshaft housing, that ends in a spline that mates up with the front yoke of the driveshaft. The 4WD tranny has a comparatively short tailshaft that ends in a spline count that mates up with the input of the transfer case. The 4WD tranny, of course, does not have a tailshaft housing. So ... to convert the 2WD tranny, you have to remove and discard both the tailshaft housing and the tailshaft. You have to find a 4WD output shaft (of the correct length and spline count to mate with whatever transfer case you have) and install that, THEN you can think about bolting up the transfer case. By the time you buy the necessary parts, it's probably cheaper to buy a 4WD transmission.

Yep. That's what the diagrams tell us. Of course, there's another variable we haven't even brought up yet. Everything we've discussed so far assumes that all the leaves are bent to concentric arches, so that load gets applied uniformly to all leaves as the load increases. One of the reasons leaf springs held on for as long as they did for rear suspensions is that it's FAR easier to make a progressive rate leaf spring than to make a progressive rate coil spring. All it takes is bending each successive leaf to a slightly larger radius, and the result is that each successive leaf doesn't start to accept load until the one above it has been partially loaded and deflected. The MJ bottom overload leaf is a crude example. In most trucks, most of the time, it just sits there and doesn't do anything. It only starts working when the upper three (or four) leaves have been loaded down to be flat enough that they contact the overload leaf. That's what I'm counting on (in reverse) with my idea to use cut-off XJ main leaves in an MJ pack to build my own "home brewed" metric ton springs. The free arch of the XJ main leaf is, in rough terms, about the same as the arch of an MJ spring sitting in a truck at curb weight. Therefore (if I'm correct), plugging the XJ leaf in won't give me any lift because it won't be trying to push UP on the other leaves. But -- it will start to carry load when the bed gets loaded up, thereby (I hope) increasing the spring rate and carrying capacity. Or I could be wrong. I think it might have happened once ... Don't have a clue. I've seen innumerable springs that have tapered ends on the leaves, and innumerable others that don't. Including springs for the same make and model vehicle that came from different subcontractors.

Of course it is possible to convert a 2WD tranny to 4WD. In terms of both time and expense, however, you would be FAR ahead of the curve to just buy a 4WD tranny and transfer case together.

That's exactly what I do, except that I don't use 1/4" screws. I think that's too big. The originals, IIRC, are 5mm. I used something just a little larger, like 6mm. But the heads on all the factory studs I have encountered were flat and uniform in size, so it was fairly easy to get my holes on-center. I drilled undersized, tapped, inserted the new screws, then just touched the heads with a wire welder to hold them. I use copious amounts of anti-seize when re-installing, hoping to avoid snapping off the repaired studs.

Length of the leaves below the main leaf doesn't make any difference. A leaf spring is nothing but a simple beam, upside down, that's working within the elastic limit of the steel. If you look at the bending moment diagram for a simple beam, you'll see that it's a wedge, with zero moment at the ends and maximum moment at the center (or the point where the point load is applied, if off-center like on an MJ rear axle). Progressively shortening the leaves only results in not wasting steel where there isn't any need to have it there because it wouldn't be doing anything, anyway. You can use the formula to calculate the rate of a spring with different thickness leaves, but not easily. For a three-leaf spring, for example, you would have to run a separate calculation for each leaf (using the same eye-to-eye measurement as the length), then add up the resultant numbers to get the total rate of the spring. I tried to Google up a beam diagram for a simple beam with a point load, but everything I found is in .PDF format and has pages of diagrams, that would be more confusing than helpful to those who don't understand what all the different diagrams illustrate.

:agree: Not only pictures. There are multiple angles you have to take into account with the front axle, and it usually results in a compromise. To reduce the likelihood of death wobble, you ideally want to keep the caster angle as close to stock specs as possible. But with 6 inches or more of lift, that results in an excessive u-joint angle at the pinion. So you have to start balancing out the pinion angle against the caster angle and hope you can find a happy medium that doesn't cause death wobble, yet doesn't eat the drive shaft u-joints alive.

Aha. So the MJ plates are different from XJ plates? I couldn't remember. There are ways to refurbish old plates wityh broken studs. Please, do not EVER throw away any that you come across. If you find 'em in a u-pull yard, grab them. With flares, if possible, but if the flares are gone or useless, get the plates anyway. And no, the rear flares on the MJ are not the same as the rear flares on a 2-door XJ. I know someone will post that (again). It is not true. I have posted the photos to prove it.

I admire your patience. The way you approached it is probebly the only good way to do it, and I'm glad to know it worked.

The factory flares all have three metal stud plates behind them to hold them in place. Last I knew, the stud plates were still available through dealer parts channels, but the MJ rear flares were not. Fronts, of course, are the same as XJ and can be bought from any of the discount auto body parts sources, such as Keystone.

It's not called "rust" when it happens to aluminum, but aluminum and salt do not coexist for long. The salt always wins.

You can either leave the XJ shock mounts there and not use them, or cut them off and throw them away. The MJ shocks mount to the spring plates, which you will most likely re-use when doing a SOA conversion.

"If it ain't broke ... don't fix it." Don't look broke to me ...

Not exactly concours d'elegance quality, but functional. I think it would be fine if the location is in the southwest, where it's warm and dry. In the rust belt, the overlapping sheets would trap snow, rain and salt, and the job would have to be repeated at the end of every winter.

This thread is degenerating. I would prefer to leave it open so that one or the other of the two parties can publicly post the invoice(s) and/or packing slip(s) to put everything on the table, but if the thread degenerates any further we'll have to lock it. How's about we just hold off on the gratuitous comments and leave the thread here until one or the other protagonist posts additional information? In the meanwhile, you can each decide whether or not you wish to do business with Motion Offroad without posting your decision here.

Don, I'm very lost as to how you are counting leaves. MJ main as #4? :hmm: Main leaf is #1. I'll have to re-check to confirm, but when I had these springs laid out in the garage I'm pretty certain the XJ main leaf was longer than the MJ #2, so the cut-off XJ leaf will go directly under the MJ main as #2, the second MJ leaf will move down to #3, and #3 will become #4. The factory overload leaf will remain as an overload leaf.

The lower seat pedestals are different between the XJ and MJ because the MJ has different floor bracing. The bucket seats from an XJ can be removed from the lower pedestals and bolted onto the pedestals from the MJ bench. The passenger side won't be adjustable unless you rig an arm for the release. Driver's side will work fine. What you want to avoid is the XJ buckets from the early (84 thru perhaps 89 or 90) years that had the "rocking chair" tilt adjustment in addition to fore-and-aft adjustment. The tilt mechanism adds height to the seats. In an MJ, unless you are well under 6 feet tall, it'll make you sit much too high.

My trucks aren't lifted. Spring under, so the thickness of the extra leaf won't have any effect at all on lift. Actually, in rough terms the added capacity is known. Some years ago one of the 4WD magazines published formulae for calculating the spring rate of both coil and leaf springs. I lost the actual formulae, but for a leaf spring, assuming all leaves are the same thickness, the rate increases in direct proportion to the number of leaves. I don't think the XJ leaf will be exactly the same thickness as the MJ leaves, so that'll skew the number a bit, but in round numbers, since the thick overload leaf doesn't count until heavily loaded, I'll be going from a 3-leaf spring to a 4-leaf spring. That should increase the rate by approximately 33 percent (rate, as in pounds-per-inch of deflection). The travel before engaging the overload spring will be the same distance, so the capacity should also be increased approximately 33 percent. Eureka! Found it! Spring rate = (leaf width x no of leaves)/72 x (1820 x leaf thickness)/spring length The entire thing is a first order equation. The main leaf will remain, so the only variable will be the number of leaves. IIRC, the diagram in the magazine measured length straight eye-to-eye, not length of the leaf along the arch.