Junkyard suspension/handling upgrades

[jeepcoma]

I'm trying to put together a list of parts I can swap from other Jeeps that will be an improvement over the stock MJ parts. I'm mostly basing the following on posts I've read on this forum, but if anyone can correct or add to the list I think it would be a good starting point for anyone wanting to get better components for street use than stock without spending lots of money on aftermarket upgrades. I'm trying to put together a list for myself of cheap upgrades to replace worn/broken stock parts, but other might find it useful too. I'm building my truck for street use so I don't mind sacrificing off-road capability for on-road performance where I will spend 99.99% of the time.

 

Front sway bar from a V8 ZJ ('97, other years?), get bushings and mounts: thicker than the MJ (1.25" vs 7/8"), better road manners in trade for off-road flex

 

Front coil springs from a V8 ZJ (years?) OR Up-Country XJ coils: a bit stiffer and about 1" (give or take 1/4") higher than stock, it would be a good match for the MT springs I put in the rear in both height and stiffness

 

ZJ (all 93-98) power steering pumps (steering gear box) (reuse MJ pitman arm) 12.7:1 vs. 14.1:1 ratio

 

ZJ pitman arm? (unknown years/models)

 

ZJ tierod? (unknown years/models)

 

Upper control arms from a WJ ('04, other years?): tubular design, (maybe) better bushings

 

Lower control arms from a WJ ('04, other years?): tubular design, better bushings

[maddzz1]

I have heard that the sway bar from an XJ with the Country package is the same as the V8 ZJ

[HOrnbrod]

I've put my comments in CAPS.

 

Front sway bar from a V8 ZJ ('97, other years?), get bushings and mounts: thicker than the MJ (1.25" vs 7/8"), better road manners in trade for off-road flex. AGREE

 

Front coil springs from a V8 ZJ (years?) OR Up-Country XJ coils: a bit stiffer and about 1" (give or take 1/4") higher than stock, it would be a good match for the MT springs I put in the rear in both height and stiffness. AGREE

 

ZJ (all 93-98) power steering pumps (steering gear box) (reuse MJ pitman arm) 12.7:1 vs. 14.1:1 ratio. AGREE (GEAR BOXES). GOOD MOD, DIRECT BOLT-IN. BUT THEY ARE BEING SUCKED UP FAST AS A CHEAP MOD BY THE 70's-80's GM CAR RESTORERS FOR THEIR QUICKER RATIO. GOOD IDEA TO ALSO SWAP IN A NEWER MODEL PUMP (1997+) ALONG WITH THE GEAR BOX AS THEY HAVE A HIGHER OUTPUT PRESSURE. THIS CAN BE DONE BY INSTALLING THE 99+ INTAKE MANIFOLD AND 97+ PUMP BRACKETS.

 

ZJ pitman arm? (unknown years/models). NOT NEEDED W. YOUR LIFT. IT'S 1" LOWER THAN YOUR MJ PITMAN ARM.

 

ZJ tierod? (unknown years/models). THE v8 ZJ TIERODS ARE A GOOD UPGRADE.  V6 ARE THE SAME AS MJ.

 

Upper control arms from a WJ ('04, other years?): tubular design, (maybe) better bushings. NOT SURE, MAYBE. HAVEN'T TRIED. :hmm:

 

Lower control arms from a WJ ('04, other years?): tubular design, better bushings

. ANY WJ IS OKAY. GOOD MOD FOR PREVENTING RUBBING W. WIDER TIRES. EXACT SAME LENGTH AS MJ LCA.

[Eagle]

I agree with Hornbrod. The drag link and the sway bar should be parallel. The ZJ pitman arm drops the outer end of the bar 1", making it NOT parallel to the track bar. This introduces bump steer, which you don't want in a street-driven vehicle.

[reson46]

I agree with Hornbrod. The drag link and the sway bar should be parallel. The ZJ pitman arm drops the outer end of the bar 1", making it NOT parallel to the sway bar. This introduces bump steer, which you don't want in a street-driven vehicle.

 

I believe you mean track bar instead of sway bar.

 

Willy

[HOrnbrod]

I believe you mean track bar instead of sway bar.

 

Willy

 

Yes, I'm sure he did.

[shelbyluvv]

V8 ZJ steering linkages are not the same as an X/MJ. The V8 ZJ steering is solid where the X/MJ is hollow.

 

Any year ZJ with the V8 will be a bolt in upgrade for your stock stuff.

[HOrnbrod]

V8 ZJ steering linkages are not the same as an X/MJ. The V8 ZJ steering is solid where the X/MJ is hollow.

 

Any year ZJ with the V8 will be a bolt in upgrade for your stock stuff.

 

Yep - you're right, my bad. I even have the ZJ V8 tierod on mine. :doh: Pretty sure the draglinks are the same though.

[Eagle]

I agree with Hornbrod. The drag link and the sway bar should be parallel. The ZJ pitman arm drops the outer end of the bar 1", making it NOT parallel to the sway bar. This introduces bump steer, which you don't want in a street-driven vehicle.

 

I believe you mean track bar instead of sway bar.

 

Willy

Right you are. Sorry, I was tired when I wrote that. I will edit my post but, of course, the quotes of the original will remain unchanged, as a permanent testimonial to my frailty.

[Darren]

Front sway bar from a V8 ZJ ('97, other years?), get bushings and mounts: thicker than the MJ (1.25" vs 7/8"), better road manners in trade for off-road flex

 

 

Why would there be a trade-off? Aren't you going to disconnect your swaybar when leaving the pavement? Quick disconnects can be made for ~$10.

[jeepcoma]

Thanks for the updates everyone. Hornbrod, most of my tech data ended up being pulled from posts you made. Glad to see you still agree with it :brows: One thing I'm still interested in is the rear sway bar which you commented on at one point. Looks like it would be a good addition for MT springs with the rest of the upgraded suspension, but only one company ever made a kit for it? Although I do recall (but of course I can't find it) reading about swapping the front swaybar for the ZJ bar and moving the stock MJ sway to the rear and it's a perfect balance.

 

Also something thing I forgot to add that I see all the time, the dual diaphragm booster seems to be a popular swap. Is that from a '95+ XJ?

[ren]

That, and the washer fluid bottle from the 97 and up XJ. You can also steal the disc setup from a ZJ with ABS (Dana 35 only, for some idiot reason :hmm: ) and it bolts on to a Chrys. 8 1/4. Fab a couple of small brackets to hold the rubber hoses at the calipers, and away you go!

Oh, I forgot: WJ knuckles for MUCHO bigger and better brakes- Aki-bonehead, er, bono 4 piston calipers,other wise twin piston and either is freakin huge compared to the stocker on our rides, true Hi-steer and true crossover steering, too. You just need the JKS spacers for your hubs, and disc from a late model TJ for the brake upgrade. :yes:

[HOrnbrod]

One thing I'm still interested in is the rear sway bar which you commented on at one point. Looks like it would be a good addition for MT springs with the rest of the upgraded suspension, but only one company ever made a kit for it? Also something thing I forgot to add that I see all the time, the dual diaphragm booster seems to be a popular swap. Is that from a '95+ XJ?

 

PST is the only company I found that makes a rear sway bar for our MJs. Unfortunately it's only for SWB models because of the differences in the shock mounts. See this link: http://www.comancheclub.com/forums/viewtopic.php?f=2&t=2355&p=156785&hilit=rear+sway+bar#p156785

 

And the 95-96 booster/master swap was a direct bolt-in for my 91 (except for bending new master-to-combo valve lines). The booster arm was correct w. no modifications to the pedal assembly (AW4).

[Eagle]

One thing I'm still interested in is the rear sway bar which you commented on at one point. Looks like it would be a good addition for MT springs with the rest of the upgraded suspension, but only one company ever made a kit for it? Although I do recall (but of course I can't find it) reading about swapping the front swaybar for the ZJ bar and moving the stock MJ sway to the rear and it's a perfect balance.

What makes you think you need a rear sway bar? And what makes you think you need one more if you change to rear springs with a higher rate (the metric ton springs)?

 

A Cherokee has a lot of weight fairly high up in the rear -- steel roof, and lots of glass. That makes for a high center of gravity. An MJ doesn't have ANY glass back near the rear wheels, and no roof back there. The center of gravity is much lower than on an XJ. The factory didn't use a rear sway bar because they didn't think one was necessary.

 

Depending on how you drive and how you intend to use the truck, a rear sway bar might be a good idea. But be sure you understand what the implications will be.

 

With automotive suspensions, as you stiffen up the suspension at one end of the chassis you induce over or understeer at that end. In other words, if you make the front stiffer (either with a bigger front sway bar or with stiffer springs) you increase understeer -- the tendency for the nose to "plow" off the road in turns. If you make the rear springs stiffer and/or add a rear sway bar, you increase oversteer -- the tendency for the rear end to lose traction and spin out on curves.

 

Going from standard rear springs to metric ton rear springs increases the spring rate approximately 33 percent. That's a big difference, and if you drive anywhere near the limit (meaning the limit of the vehicle's ability to stay on the road, not the speed limit), you will definitely feel the difference. You may not like the difference, because you may get more oversteer than you'll be comfortable with. If you add a rear sway bar on top of that, I'll almost guarantee that you'll have serious enough oversteer that you really won't like it.

 

On the other hand, if you don't drive near the limit, none of this will matter and there is no reason for you to add a rear sway bar. Just toss in the metric ton springs and call it good. Adding a rear sway bar is for tuning a competition-oriented suspension and IMHO should not be done by 98% of the people on the road.

[HOrnbrod]

On the other hand, if you don't drive near the limit, none of this will matter and there is no reason for you to add a rear sway bar. Just toss in the metric ton springs and call it good. Adding a rear sway bar is for tuning a competition-oriented suspension and IMHO should not be done by 98% of the people on the road.

 

All the research I did on MJ rear sway bars was before I added the new metric ton springs. I haul around the big old Leer camper shell, and the increased body roll was evident sliding around corners with it on. After adding the MT springs and leveling everything up, the oversteer did increase a bit as Eagle states, but it was a good predictable oversteer and much easier to control when deliberately going into a power slide. The bigger ZJ sway up front, stiffer WJ LCAs, and other ZJ suspension parts helped a lot too. And combined w. the quick ratio ZJ steering box, this thing handles really really good w. my modest 3" lift. Not a sports car by any means, but pretty damn good for a p/u truck. :cheers:

[Eagle]

Yes, I'd say putting a top-heavy camper shell on would be a good reason for adding a rear sway bar. For something like that, I'd want the biggest bars I could find ... on both front and rear.