Eagle

Since you asked: I would remove it. After having had one explode in a panic stop, I would not trust any one I found used. I'd much rather have brakes, and then deal with the consequences of having too much braking bias to the rear. Wilwood makes an adjustable proportioning valve if you need one, but it's not a replacement for the height sensing valve (physically), and it doesn't automatically compensate for load.

True enough ... but most "31s" tend to run about 30-1/2" in diameter. The 265s may be taller because they're on narrower rims, so the sidewalls are squeezed in a bit. Plus, of course, they have full tread. My 31s are on 7" Jeep rims and they work on the XJ at stock height (subject to the usual caveat about LCA rubbing).

The cutaway was mine. Since the bypass port (the one that wasn't drilled all the way through on the one I cut open) is the one you block when eliminating the rear height-sensing valve, it doesn't make any difference if that port is drilled all the way through or not. Don't make extra work for yourself.

What's the track on a Scout? I think those axles are pretty narrow ...

I don't think I've even seen a 265/75-15. Based on the numbers, it should be 10.4" wide at the sidewall and 30.4x" in diameter ... in other words, almost exactly the same as a 31x10.50-15. I'm running 31s on the '88 XJ (with no lift) right now ... which is why/how I speak so authoritatively on how they fit and where they rub.

I think it was a few years ago, in Jp Magazine. I haven't had a subscription to that rag for a couple or thre years, but I'm pretty sure that's where I saw it, so it would have been at least that far back. There would be no "upgrade" to using ZJ brakes and hubs -- they are the same as XJ. In fact, the ZJ ceased to exist before Jeep went back to one-piece rotors on the XJ, so arguably rotors from a 2000 or 2001 XJ would be an upgrade for any ZJ, not the other way 'round.

His first post in this thread says they are 1/2" Yes, 9/16" can work. They are a little tight and may need to be lightly sanded and then greased or (preferably) coated with anti-seize, and then tapped through, but they will work. 9/16" is 14.29mm

Please confirm what you have for a drive train. The XJ was not offered from the factory with a V6 after 1986. Where did you get this tranny from, and are you certain it's from a 91 XJ?

I think you should double and triple check that angle before you do anything. That's twice the stock caster angle, and I've never heard of any lift combination that produced anything like that.

Define "work." Wrangler rims are the same as Cherokee and Comanche rims. There is no disagreement as to what will happen if you put 31x10.50s on those rims on a stock MJ. They WILL tuck up inside the sheet metal and flares with no problems. They WILL rub on the lower control arms when the steering is turned to full lock. To put that in perspective, with a stock truck on stock tires the steering has 3-1/2 turns lock-to-lock. Running 31s, I lose less than 1/4 turn at each extreme, so my steering is reduced to 3 turns NON-lock to NON-lock. 97.32 percent of the time it makes no difference at all. The only time it makes any difference is when trying to turn sharply to get into a tight parking space. Changing to aftermarket rims with less backspacing eliminates the rubbing on the control arms, but creates problems with the tires hitting the flares and/or sheet metal. Personally, I'll deal with the minimal inconvenience of rubbing the lower control arms rather than bash up my bodywork and maybe cut a tire any day.

No. It's a locker. Friction modifier is required with clutch type limited slips.

The AX-15 is (was) made by Aisin-Seiki in Japan, and I believe it was also used in some Toyotas. Whether or not the Jeep version and Toyota version are 100% interchangeable I don't have a clue.

A 2WD transmission can be converted to 4WD ... but it isn't worth the time, effort and $$$ to do it. Just buy a 4WD tranny and transfer case as an assembly from a junkyard and call it good. Get the linkage and transmission controller from the same vehicle and you're good to go.

I'll have to check the '86 out back. Most likely some previous owner swapped the front axle. Be sure you torque that nut back to 175 foot-pounds.

Guys, if they are the same as the LCA bolts, they are not 1/2" bolts. The LCA (and UCA) bolts are metric, which is why so many of the control arm kits that come with SAE bolts rattle.

If it's the one-piece (as shown in the photo in the link I provided), the spindle nut isn't torqued on. It has to be tightened and then backed off slightly to allow the bearings to operate properly. As someone already posted, you should be able to remove that nut with a Channel-Lock plier. Did you remove the cotter pin through it? After the nut is correctly set, there's a sheet metal castle-nut retainer that fits over it and is locked in position by a cotter pin. Maybe you already know this, but I mention it because on this here Internet we have no way of knowing your level of experience.

I've bought complete trucks in equal or better condition for $200. What are you going to haul wood in? As noted, you'll need a box. Good luck finding one. About the only good thing there is that clearance for big tires won't be a problem in the rear. I wouldn't even consider this one, but I like to keep MJs as complete and original as possible. If you would be chopping it up anyway, then by all means chop on this one.

:agree: Not certain, but I think even the fuel pump operates at a different pressure.

No. There is no "supposedly" about it. That is what the second line does. What you're missing is that the front junction block also has the slider switch that controls the brake system failure warning light. I don't know for certain, but I suspect it's probably against both Federal and state law to remove or disable that. Why do you think you need to replace it with tees to use an adjustable proportioning valve? Leave the OEM distribution block in place. Plug the outlet for the rear bypass line, and put your adjustable valve in the one line you run to the back. Done.

Some of the 2WD XJs and MJs used a standard, passenger car type front spindle and a one-piece hub/rotor. Other years (and I still haven't taken the time to figure out which years) the 2WD vehicles used the same hub/bearing unit as the 4WD and have a stub shaft going through to hold everything together. Sounds like that's what this vehicle is. The socket should be a 36mm. BUT ... the hub doesn't hold the rotor on. If this truck has the 4WD style hub/rotor, the rotor is a separate piece that should pop right off once the caliper has been moved out of the way. The axle nut only holds the hub in place, not the rotor. Reference: viewtopic.php?f=2&t=19601

What's the reference in your signature (and in at least one of your posts) to "DGB 4 speed A/T (AW-4)"? The MJ automatic used behind the 4.0L engine is an Aisin-Warner ... which is what the "AW" in AW-4 stands for. Who or what is DGB?

I also gravity bleed the load sensing valve at the feed and bypass line by cracking the fittings at the valve. And I do it for about two hours, keeping the master cylinder front and rear tanks full. SOP for gravity bleeding is all wheel calipers and any additional biasing valves. Should have mentioned that..... Thanks for your correction Eagle. No need for CAPS........ But the bypass inlet at the front metering block is closed by the shuttle valve unless the front brakes have failed and the slider has moved to open that inlet. I don't think your gravity bleed is actually flowing brake fluid through the bypass line, I think it's back-feeding from the primary line.

Rear lock-up is a potential problem when the load-sensing valve is removed, but IMHO swapping in a Cherokee proportioning valve is not the answer. I've been running the '88 MJ with no load-sensing valve ... I had no choice, it blew out in a panic stop. I had the rear wheels lock up once, when I was approaching a stop sign going down a fairly steep hill and there was sand on the pavement. Aside from that, it just feels like I have better brakes than any other XJ or MJ I've ever driven. Why isn't the XJ proportioning valve the solution? I have a couple of reasons. The first is that the XJ proportioning valve is prone to gum up, resulting in NO rear brakes. That's the sutuation with my '8 XJ right now, but I have other things on it that have to get fixed first (like heat). The second is the way I think the XJ valve works. If you open one up, there's a plunger, a cup washer (which most people refer to as an O-ring, but it isn't), and a spring. The spring tends to hold the cup washer toward the rear of the bore, such that NO fluid can pass to the rear brakes. Only when the pressure is high enough to compress the spring does the cup washer and plunger move out of the way to allow brake fluid into the rear brake circuit. At least, that seems to be the only way it can operate, based on the way it's constructed. What does that mean in operation? If I am correct, it means that under most normal conditions you are stopping only with the front brakes. You get rear brakes only under heavy/hard braking. BUT ... that's exactly when the vehicle weight is shifted onto the front wheels and the rear brakes are most likely to lock up prematurely, so in reality that exactly when you DON'T want full braking to the rear. I'm happy with the MJ metering block and no proportioning valve. I know I can't drive like a maniac when the pavement is slippery ... so I don't. I don't think the tire size makes much difference. With larger tires you have a bigger contact patch, but you also have the same weight on the contact patch, so the pressure of the tire on the pavement is lower in psi. In fact, if it works like driving in snow, you'd probably do better with smaller/narrower tires.

A gravity bleed CANNOT bleed the bypass line. Your brakes may work fine under normal conditions, but if you lose the front brakes and there's air in the bypass line -- you won't have any rear brakes, either.

My '88 Cherokee still has the original Peugeot tranny, with 287,000+ miles on it. No problems except, as noted above, it doesn't like to shift into 2nd gear when cold. Guess what? Neither does the AX-15, and neither does the NVG3550 in my 2000 XJ. Also as noted above: DO NOT resurface the flywheel. That's a no-no. :no: