MetalCloak Duroflex Lower Front 4-Link Long Arms, Jeep Wrangler JK

In a long arm setup the front lower arms do the most work: they carry drive and braking forces, set the pinion angle, and decide how much of the available travel you actually use. Factory arms are short, and on a big lift they work at an angle that ruins the handling — a longer arm solves that by definition.

These are built from 2.0in DOM tube with a 1/4in wall, CNC formed for tyre clearance, with forged adjustable ends and Duroflex joints at both ends. The joints are the real product here: they give 68° of articulation per arm against roughly 40° for a typical arm — and they do it without the noise and vibration that ordinary flex joints cost you.

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

This item is a pair of front lower arms and nothing else. A long arm conversion also needs frame brackets, because the factory lower control arm mounts have to go — hence the "cutting and welding" in the install notes.

If you are moving to a 4-Link setup for the first time, the right purchase is the complete front 4-Link system, which we stock — it contains these same lower arms plus the upper arms and the full set of brackets. Buying it, you do not need this item separately.

These arms on their own make sense when: you already run a 4-Link and have damaged a lower arm; you are building on your own brackets; or you are replacing the arms alone.

The Duroflex joint — this is what you are paying for

MetalCloak fits its patented Duroflex 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 and vibration; 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 synthetic silicone grease, reassemble.

Construction

• 2.0in DOM tube with a 1/4in wall – CNC formed, with a bend for tyre clearance.
• Forged adjustable ends – 37% higher fatigue strength than cast parts, which is a real difference when they meet rocks.
• 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 × lower front long arm (a pair)

The kit contains no frame brackets and no hardware — those are part of the complete 4-Link system.

Technical data

• Application: Jeep Wrangler JK, 2007–2018, front axle, lower arms
• Contents: a pair of arms
• Tube: DOM ø2.0in (50.8 mm) with a 1/4in (6.35 mm) wall, CNC formed
• Base length: 33¼in (approx. 845 mm), adjustment ±5/8in (approx. ±16 mm)
• Ends: forged, threaded, adjustable, 1in–1/4 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 1/2in bolt; joint width ø2⅝in
• Finish: gold zinc
• Installation difficulty: difficult — licensed installer recommended
• Body modification: cutting and welding
• Time to install: 3–4 hours
• Shipping weight: approx. 18.1 kg
• Country of manufacture: USA

Who they are for

For vehicles already running a 4-Link that need the lower arms replaced — after damage, or during a suspension rebuild. And for people building on their own brackets who want finished, strong arms with good joints rather than fabricating them.

If you are only now planning the move to long arms, buy the complete system. It works out cheaper than assembling it from separate items, and you get everything you need.

Installation notes

MetalCloak rates the install as difficult and recommends a licensed installer, allowing 3–4 hours. Cutting and welding are required — the factory lower control arm mounts have to be removed and the long arm brackets take their place.

Afterwards, wheelbase and pinion angle have to be reset with the arm adjustment, followed by an alignment. Szekla4x4.pl is an authorised MetalCloak dealer with a workshop specialising in off-road suspension — send us your configuration and we will tell you exactly what is needed.

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.
• Maintenance-free joints that, when the time comes, rebuild in minutes.

Not sure whether you need the arms alone or the whole system? Get in touch — it is a several-thousand-zloty question, worth asking before you buy.

Frequently asked questions

Is this a complete long arm conversion kit?

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

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

No. The complete system contains these same lower arms.

Does fitting require welding?

Yes. MetalCloak lists cutting and welding as required, because the factory lower control arm mounts have to be removed.

What is the adjustment range?

A base length of 33¼in with ±5/8in (approx. ±16 mm) of adjustment.

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.