MetalCloak Duroflex Rear Upper Long Arms, Jeep Wrangler JK and JL

The rear upper arms set the pinion angle and keep the axle from walking under load. After a lift they work at an angle the factory bushings were never designed for — and that is where the compromise starts: either comfort or range of movement.

These arms settle it with the joint. 1.5in DOM tube with a 3/16in wall, CNC formed for clearance, forged adjustable ends and Duroflex joints at both ends: over 68° of articulation per arm against roughly 40° for a typical arm — without the clunk and vibration that ordinary flex joints cost you.

Unlike the front lower arms, this install is simple: 1–2 hours, bolt-on, with no modification to the vehicle at all.

⚠ These are arms only — check whether you need the whole system

This item is a pair of rear upper arms and nothing else. If you are moving to a rear long arm setup for the first time, the right purchase is the complete rear 4-Link system, which we stock — it contains these same upper arms, the lower long arms, the lower control arm brackets and all the hardware. Buying it, you do not need this item separately.

The upper arms alone make sense when: you already run a rear 4-Link and are replacing the upper arms; you have damaged one; or you want to improve just the upper arms while keeping the rest of the setup — which is a reasonable thing to do here, because the install needs no work on the vehicle at all.

The Duroflex joint — this is what you are paying for

MetalCloak's patented joint: a vulcanised elastomer reinforced with DuPont™ Kevlar® fibre, self-centring, with a true bearing surface on the outside of the bushing.

• Over 34° of misalignment per joint, over 68° per arm – against roughly 40° for a typical arm. That translates directly into usable suspension travel.
• Vibration damping and self-centring – ride quality stays at factory level. Ordinary flex joints are bought at the price of noise; here there is no such price.
• Absorbs micro-movements – the millions of small rotational movements of daily driving that cause the micro-wear which destroys ordinary flex joints.
• No binding of the control arms – the outer surface of the bushing works as a bearing and breaks free when called for.
• Maintenance free, yet rebuildable – no annual replacement of parts as with typical flex joints. To rebuild: pull the bushing, clean it, add Teflon-impregnated silicone grease, reassemble.

Construction

• 1.5in DOM tube with a 3/16in wall – CNC formed, with a bend for clearance.
• Forged adjustable ends – 37% higher fatigue strength than cast parts.
• Joints centred and aligned – MetalCloak points out that most makers build their arms misaligned from centre because it costs less. Aligned joints mean less wear and an easier install.
• Gold zinc plating over the whole arm.

What's in the kit

• 2 × rear upper long arm (a pair)

Technical data

• Application: Jeep Wrangler JK 2007–2018 and Jeep Wrangler JL 2018+, rear axle, upper arms
• Contents: a pair of arms
• Tube: DOM ø1.5in (38.1 mm) with a 3/16in (4.76 mm) wall, CNC formed
• Length: 32½in (approx. 826 mm)
• Ends: forged, threaded, adjustable, 1¼in–12 UNF, precision locking nut
• Joints: Duroflex at both ends, vulcanised elastomer with DuPont™ Kevlar® fibre
• Misalignment: over 34° per joint, over 68° per arm
• Mounting: for a 9/16in bolt; joint width ø2⅝in
• Finish: gold zinc
• Installation difficulty: easy
• Body modification: none
• Time to install: 1–2 hours
• Manufacturer's instructions: none provided
• Shipping weight: approx. 13.2 kg
• Country of manufacture: USA

Who they are for

For vehicles already running a rear 4-Link that need the upper arms replaced — after damage, or during a suspension rebuild. And for anyone who wants to improve the upper arms without rebuilding the whole setup: this is one of the few items in the family you can fit in an hour or two, with no cutting and no welding.

Installation notes

MetalCloak rates the install as easy and allows 1–2 hours, with no body modification — the arms go into the existing mounts. No written instructions are supplied with this item.

After replacing the arms the pinion angle has to be reset, followed by an alignment — MetalCloak recommends one after any suspension work. Szekla4x4.pl is an authorised MetalCloak dealer with a workshop specialising in off-road suspension.

Why they are worth it

• 68° of articulation per arm instead of 40° — you see it on the trail, not just in a table.
• Factory-bushing comfort with flex-joint range of movement.
• Forged ends with 37% higher fatigue strength than cast ones.
• Bolt-on in 1–2 hours, with nothing modified on the vehicle.

Not sure whether you need the upper arms alone or the whole rear system? Get in touch and we will tell you honestly.

Frequently asked questions

Is this a complete rear long arm conversion?

No. It is a pair of rear upper arms only. A full conversion also needs the lower long arms and brackets — those are part of the rear 4-Link system, which we stock.

Do I need these if I am buying the complete rear 4-Link system?

No. The complete system contains these same upper arms.

Does fitting require welding or drilling?

No. MetalCloak specifies: no body modification, easy install, 1–2 hours. This is the simplest item in the long arm family to fit.

Do they fit both the JK and the JL?

Yes. MetalCloak lists compatibility with the Wrangler JK 2007–2018 and the JL from 2018 on.

Do the Duroflex joints need servicing?

Not routinely — MetalCloak describes them as maintenance free. A rebuild means pulling the bushing, cleaning it, adding Teflon-impregnated silicone grease and reassembling.

Will they clunk like flex joints?

No. The Duroflex is a vulcanised elastomer rather than a metal joint — it damps vibration and self-centres, so ride comfort stays at factory level.

Is an alignment needed afterwards?

Yes. MetalCloak recommends an alignment by a specialist after any suspension change; with control arms the pinion angle has to be set as well.