ZJ Grand Cherokee Long Arm Install: Upgrading to the Core 4x4 Crawl Series

The Jeep Grand Cherokee ZJ (1993–1998) is one of the most capable platforms for serious off-road builds — and upgrading to a true long arm suspension kit is one of the biggest improvements you can make. In this guide, Spence from Core 4x4 walks through the ZJ long arm kit, explains what sets a true four-link apart from a standard radius arm setup, and shows a real-world arm swap from the Camp Series to the Crawl Series on a ZJ that has been beating trails for six years.

Whether you are planning a fresh ZJ long arm install or upgrading your existing Core 4x4 arms to the double-adjustable Crawl Series, this post covers the kit contents, bracket details, measuring techniques for offset arms, and the lessons learned from thousands of miles of hard off-roading on this Grand Cherokee.

Fitment: Jeep Grand Cherokee ZJ 1993–1998 (Straight 6 and V8 models — crossmember differs by engine)

Why a True Four-Link Long Arm Kit for the ZJ?

Most aftermarket ZJ suspension kits use short upper control arms paired with long lower radius arms. That setup is simple, but it comes with serious compromises: axle wrap under throttle, bind during articulation, and limited overall flex. The geometry simply is not optimized for real off-road use.

The Core 4x4 ZJ long arm kit is a true four-link system, front and rear. That means four independent control arms per axle — upper and lower — all running at proper lengths and angles to allow maximum articulation without bind. You can also run it as a three-link configuration depending on your steering setup. Either way, it is the ideal geometry for any ZJ Grand Cherokee that sees serious trail time.

What’s in the ZJ Long Arm Kit

The complete Core 4x4 ZJ long arm kit includes everything you need for a full front and rear conversion:

Camp Series vs. Crawl Series: What’s the Difference?

Core 4x4 offers two arm tiers for the ZJ long arm kit. The ZJ in this video originally had the Camp Series and is now upgrading to the Crawl Series.

The big advantage of the Crawl Series is that both ends are threaded, so you can dial in your arm lengths and alignment without removing anything from the Jeep. That makes setup significantly easier, especially when you are chasing alignment specs after the install. The arms are built from the same 5/16” wall DOM tubing — strong enough to set the Jeep down on a rock without worrying about bending. In Core 4x4’s history, only one Crawl arm has ever been bent, and that was from driving off a cliff.

How the Brackets Look After 6 Years of Off-Roading

One of the reasons Spence wanted to film this swap was to show how the kit holds up over time. This ZJ has been strictly off-road for six years in Utah — including salt exposure from winter road treatment. The brackets showed no cracked welds, no broken tabs, and no structural issues. The original automotive spray-paint finish had chipped in places (Core 4x4 now powder coats everything), but the steel underneath was solid.

The one issue found: one rear arm had stripped threads because the early kit had the arm lengths slightly short, leaving only about half an inch of thread engagement on the Johnny Joint. That is exactly the kind of issue the Crawl Series double-adjustable design fixes — the longer adjustment range gives you much more thread engagement and room to fine-tune.

Bracket Install Overview: What the Job Involves

While this video focuses on swapping arms (not a full kit install from scratch), Spence walks through the bracket details so you know what to expect if you are starting fresh:

Rear Brackets

• Each rear bracket requires a 1-1/2” hole saw to cut the center hole in the frame
• Line the bracket up with the pinch seam on the frame, mark the center hole, and cut
• Two nut tabs hold the bracket against the frame, plus two through-bolts that sandwich the frame
• The rear-most bolt also clamps the rear upper control arm — this is the last bolt you install on that bracket

Front Brackets

• Same 1-1/2” hole saw for the center hole
• Five holes total per side on the frame brackets: three on the bracket face plus two through-bolts
• Significant trimming of the pinch seam is required for upper arm clearance and bracket fitment
• The back edge of the bracket lines up with the body-to-subframe overlap seam — that is your alignment reference for drilling

Pro tip: The front install is similar to the Core 4x4 XJ Cherokee long arm kit. If you want a detailed walkthrough of that bracket work, check out the XJ long arm install video on the Core 4x4 YouTube channel — the techniques transfer directly.

How to Measure Offset ZJ Control Arms

The upper control arms in this kit have an offset — either a bent U-bracket or a slight curve to clear exhaust and driveline components. That means the outside measurement and inside measurement of the arm will be different. Here is how to handle it:

1. Measure the outside (longer) dimension bolt-to-bolt
2. Flip the arm and measure the inside (shorter) dimension
3. Average the two measurements — that is your true arm length

In this swap, the arms measured about 32-3/4” on the outside and 32-1/4” on the inside, giving a true length of approximately 32-1/2”. Matching the existing length means you do not have to realign the Jeep after the swap — a big time saver.

Thread Engagement and Jam Nuts: Do Not Skip This

One of the most important takeaways from this install is thread engagement. On the old Camp Series arms, some Johnny Joints only had about 2-1/2 inches of thread, leaving roughly half an inch of actual engagement in the arm body. That is a recipe for stripped threads, and sure enough, one arm on this ZJ had stripped out.

The Crawl Series arms solve this with double-threaded adjustability that provides significantly more thread engagement and adjustment range. But regardless of which arms you run, keep your jam nuts tight. A loose jam nut allows the joint to back out under vibration, which leads to thread failure. Spence recommends tightening the jam nuts before bolting the arm onto the Jeep, especially on the upper arms where a crow’s foot wrench is hard to fit once the arm is installed — particularly near the exhaust.

Pro tip: If you know your arm length, pre-set it and lock the jam nuts at the workbench. The upper front arms sit close to the exhaust manifold and crossmember, making it very difficult to get a wrench on the jam nut once installed.

Passenger Side Upper Front: The Trickiest Bolt

The most difficult part of this entire job is the passenger-side upper front control arm bolt. The exhaust runs right along the bracket, blocking access. The solution is to drop the transfer case crossmember slightly and pull the exhaust down just enough to reach the bolt. Plan for extra time on this one — it is a bear on every ZJ.

Rubber Bushings: Torque at Ride Height

If your ZJ long arm kit uses rubber bushings on the axle side (as the Camp Series does), do not final-torque those fasteners with the Jeep on the lift. Rubber bushings have a fused crush sleeve that locks its position when torqued. If you torque at full droop, the bushing pre-loads in the wrong position and wears out prematurely. Lower the Jeep to the ground and torque all rubber-bushing bolts at ride height with the full weight of the vehicle on the suspension.

Johnny Joints (like the ones on the Crawl Series) do not have this restriction — they articulate freely regardless of when you torque them.

The Finished ZJ

With all eight Crawl Series arms installed, this ZJ Grand Cherokee is ready for another chapter of hard off-roading. The new double-adjustable arms provide better thread engagement, easier alignment adjustments, and Johnny Joints on every connection point for maximum articulation. The original brackets held up perfectly after six years, confirming the long-term durability of the kit.

Tools Required

• Two-post lift or floor jack and jack stands
• Socket set (standard and metric)
• Torque wrench
• Crow’s foot wrench set (for jam nuts in tight spaces)
• Tape measure
• 1-1/2” hole saw (for full kit install only)
• Drill and drill bits (for full kit install only)
• Grease and grease gun (for Johnny Joints)
• Penetrating fluid (PB Blaster or equivalent)
• Cheater bar / pry bar (for axle manipulation)

Frequently Asked Questions

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Fitment: Jeep Grand Cherokee ZJ 1993–1998 (4.0L I6 & 5.2L/5.9L V8). Questions? sales@core4x4.com | support@core4x4.com