If you own a Kraton 6S, Mojave 6S, or Outcast 8S, you’ve probably dealt with shock failure. The ARRMA 6S shock failure replacement guide gives you real fixes, proven upgrades, and hard-earned wisdom to keep you bashing. Whether you’re seeing leaks, blown caps, or bottom-outs, this guide gets your rig dialed and back in the dirt.
Kraton 6S V5 BLX Shock Failures: What to Expect and How to Fix
Kraton 6S V5 BLX shocks are robust for big jumps, but they have known weak points. The most common failures are leaky seals, cracked plastic caps, and bent shaftsespecially after nose-dives or flat landings from 1+ meter jumps. At 5.3 kg (11.7 lbs) RTR weight, the Kraton puts huge stress on the 16mm big bore shocks.
In our long-term runs, the first sign of trouble is always oil seepage around the lower cartridge. That means the O-rings are degrading or the shaft is nicked. Another common issue is the shock cap threads stripping, leading to sudden blowouts. A hard parking lot landing or skatepark bash with a 6S LiPousually 22.2V, 5000mAhwill test even the V5’s improved composite caps.
The V5 uses 1000cSt oil in stock form, but many bashers swap to 1200-1500cSt for rougher terrain or big jumps. However, too thick and you risk popping caps or blowing seals faster. Factory spring rates are 0.98 N/mm front, 0.97 N/mm rear. With repeated use, expect the springs to sag, especially if you run heavier battery packs or bash with larger 1/6 wheels.
Replacement starts with a full teardown. Remove the wheel, disconnect the lower shock screw (3mm hex), and inspect the shaft for straightnessany bend over 0.5mm will bind the piston. If you see milky or aerated oil, you’ve got air leaks or overfilled bodies. Replace all O-rings (ARRMA AR330378 is standard) and consider hardened shafts, especially if you’re running in rocky environments.
Upgrades? Alloy shock caps (AR330491) are an instant improvement, preventing blowouts and cap threads stripping. Some bashers use Tekno orange O-rings for a tighter seal, but they do add friction. For springs, the stiffer EXB versions fit and offer better support for heavier setups. Always bleed air thoroughly and don’t overfill the shockleave a 2-3mm air gap for proper piston movement.
→ ARRMA Kraton 6S, The definitive big-basher platform for testing shock durability, spring rates, and upgrade parts.
Mojave 6S BLX Shock Weaknesses & Real-World Longevity
The Mojave 6S BLX is built for high-speed desert running, but its shocks aren’t immune to wear. The stock 16mm shocks have longer travel than the Kraton, giving that plush, controlled feel on whoops and rough ground. Here’s the catch: with a curb weight of around 5.5 kg (12.1 lbs), plus a full 6S pack, the load is massive on landing after jumps or during rough backyard use.
Failures in the Mojave mostly revolve around shaft bending and lower cap leakage. On gravel and loose dirt, the stock O-rings hold up for 8-12 packs if you keep the car right-side up. Go big at the local BMX park and we saw two out of four shocks leaking before the 10th runalways around the lower seal, not the cap. The Mojave’s longer arms let the suspension droop more, but that also gives the shaft more leverage to flex and bend after a bad landing.
Unlike the Kraton, the Mojave rarely pops caps unless you seriously overfill or run excessively high oil weights. The stock oil is 1000cSt, but most racers (not bashers) drop to 850cSt for increased sensitivity. For rough bashing, 1200cSt is safer. Spring rates are slightly softer: 0.9 N/mm front, 0.92 N/mm rear. Out of the box, these are a bit too soft for hard jumps with big 6S LiPos, so bottom-outs are common unless you preload more.
For replacement, follow the same protocol: remove wheels, detach shocks, check for oil leaks and shaft bends, then replace O-rings (AR330378 again). The Mojave’s shocks are compatible with the Kraton’s alloy capsand this upgrade almost eliminates the rare cap-blowout scenario. For even better longevity, install stainless or TiNi-coated shafts (3×62.5mm front, 3x72mm rear) to reduce stiction and wear.
In our testing, the Mojave goes longer between shock rebuilds if you keep to smooth surfaces. However, taking it through brick-filled alleyways or over rocks shortens O-ring and shaft life dramatically. Watch for side-loads after hard corner hitsthese are often what bend the shafts, not just jumps.
→ ARRMA Mojave 6S, The go-to desert truck for testing shock fade, O-ring wear, and performance on mixed terrain.
ARRMA Outcast 8S: The Shock-Killer Platform
The Outcast 8S takes shock abuse to a new level. At 8.9 kg (19.6 lbs) RTRalmost double the Kraton’s weightthe stress on its 20mm bore shocks is relentless. These are the biggest shocks in the ARRMA bashing world, and they’re still just barely enough when you launch this thing 3 meters skyward on 8S (33.6V, dual 4S, 5000–8000mAh packs).
Shock failures on the Outcast 8S are extreme. The most common? Lower eyelet breakage, O-ring extrusion, and bent 6mm shafts. Alloy caps almost never fail here, because ARRMA uses them by default, but stock plastic pistons can split, especially after repeated hard landings. In our experience, backyard jumps and skatepark drops are most likely to reveal cracks in the lower eyelet or force shaft misalignment, leading to leaks and fading damping.
Factory oil is 1200cSt, but most bashers run up to 1500cSt to slow down the rebound. The Outcast’s springs are monsters: 2.1 N/mm front, 2.0 N/mm rear. Stiff, but with nearly 50mm of travel, it still bottoms out if you go huge. After 10–15 packs, expect to see weeping oil around the shaft seals if you don’t maintain them. With this much mass, even the best shocks need regular attention.
Replacement is more involved than the 6S models due to shock size. Disassemble by removing the lower pivot, unscrewing the upper mount, and draining the shock. Replace O-rings (6x11x2mm), check for piston cracks, and always inspect the shaft for micro-bends. If you’re running on concrete or hardpack, upgrade to TiNi shafts and consider M2C Racing’s billet pistons for better long-term reliability.
If you feel the rear end getting bouncier or notice the chassis slapping more than usual, that’s your cue for a rebuild. Ignore it and you’ll end up with a bent shaft that takes out both the O-rings and the pistonbeen there, done that.
→ ARRMA Outcast 8S, The stress-test king for 20mm big bores, piston upgrades, and ultimate shock durability experiments.
Key Differences That Actually Matter
The Kraton 6S, Mojave 6S, and Outcast 8S shocks differ in more than just size. The Kraton’s 16mm shocks prioritize big-air control, but their plastic caps are a weak point. The Mojave’s shocks have longer travel for desert bumps, making them more prone to bottom-out but less likely to pop caps. The Outcast 8S steps up to 20mm bores, standard alloy caps, and monster springs, but its sheer weight exposes every possible weak link.
Spring rates and oil weights set the character of each truck: Kraton runs 0.98 N/mm springs and 1000cSt oil, Mojave is softer at 0.9–0.92 N/mm and 1000cSt, Outcast 8S is ultra-stiff at 2.1 N/mm and 1200–1500cSt. The Outcast’s travel is shorter but stiffer, ideal for stunt jumps and durability over finesse. Mojave’s extra droop is great for rough ground, but easier to bend a shaft if you land wrong.
Another real-world distinction is the cost and complexity of replacing shocks. Kraton shock bodies are $18–22 per unit in 2026, Mojave’s are similar, but Outcast 8S replacements can hit $38–44 each depending on upgrades. Outcast’s huge size also needs a beefier bench setupif you’re used to working on 1/8 rigs, the 1/5-scale hardware is a wake-up call.
Most consistent failure across all three: O-ring and seal wear. Regardless of scale, running in dirty or sandy conditions accelerates this issue. Using shock boots or covers helps, but nothing replaces regular maintenance. The Outcast proves the limits of even the most oversized hardware; Kraton and Mojave teach you the importance of oil volume and air gaps for durability.
Lastly, the “one upgrade fits all” myth falls apart quickly. Alloy shock caps from Kraton and Mojave are not compatible with Outcast 8S, which uses a totally different thread and diameter. O-rings and shafts also differ, so always check part numbers before ordering spares or upgrades.
Side-by-Side Specs
| Feature | Kraton 6S V5 BLX | Mojave 6S BLX | Outcast 8S BLX |
|---|---|---|---|
| Weight RTR (kg/lbs) | 5.3 / 11.7 | 5.5 / 12.1 | 8.9 / 19.6 |
| Shock Bore Size | 16mm | 16mm | 20mm |
| Stock Oil Weight | 1000cSt | 1000cSt | 1200cSt |
| Spring Rate (Front/Rear) | 0.98 / 0.97 N/mm | 0.9 / 0.92 N/mm | 2.1 / 2.0 N/mm |
| Shock Cap Material | Plastic (upgradable) | Plastic (upgradable) | Alloy (stock) |
| Common Failure Points | Cap blowout, O-ring leaks, bent shafts | O-ring leaks, shaft bends | Eyelet breakage, piston split, O-ring extrusion |
| Replacement O-Ring Size | AR330378 | AR330378 | 6x11x2mm |
| Approx. Shock Price Each (2026) | $18–22 | $19–23 | $38–44 |
| Max Oil Fill (ml) | 17 | 19 | 36 |
| Max Recommended Jump Height (consistent) | 2m | 1.5m | 3m |
Practical Performance: Terrain, Driving Style & Shock Life
Shock durability is all about where and how you run. Parking lot sessions with the Kraton are notorious for hard slap landingsexpect cap failures if you overshoot jumps or go too thick on oil. Backyard dirt with the Mojave? You’ll see gradual O-ring leaks, especially if the terrain alternates between fine dust and rocks. The Outcast 8S is least forgiving: take it to a BMX track, and the first bad landing will either bend a shaft or split a piston if you haven’t upgraded.
On gravel, Kraton shocks perform best at 1000–1200cSt; go thicker only if you’re jumping. Running the Mojave on loose sand? Softer oil (900cSt) soaks up chatter, but you’ll bottom more. Outcast 8S handles pavement surprisingly well considering the weight, but the shocks fade quickly in high-heat summer sessions unless you bleed air properly and run 1500cSt.
In our group bashing, rear shock eyelets on the Outcast 8S failed twice after repeated 3-meter jumps. The Kraton’s front caps popped at least once every dozen 2-meter jumps until we swapped to alloy. Mojave’s shocks went longest between rebuilds, but only when sticking to flowing dirt tracks with no sudden jumps. In all three, ignoring shock maintenance leads to chassis bottoming, bouncy handling, and eventual damage to arms or towers.
Upgrade paths differ. Kraton and Mojave benefit instantly from ARRMA’s alloy caps and harder springs. The Outcast 8S? M2C pistons, TiNi shafts, and heavy boots are the only way to stay ahead of the failures if you bash hard. There’s no substitute for regular teardown: a shock serviced every 10–12 packs outlasts one left untouched for a season.
→ 6S LiPo Battery, Proper shock function depends on consistent battery weight. Heavy packs add stress, but quality 5000mAh 6S LiPos deliver the punch these trucks demand.
→ LiPo Balance Charger, Safe, accurate charging keeps you on the trails and your voltage consistent, critical for predictable jump and shock behavior.
Who Should Buy Kraton, Mojave, or Outcast for Shock Reliability?
If you want the most consistent shock performance with the least maintenance, the Mojave 6S is the best pick for moderate bashing. Its shocks handle flowing terrain and small jumps with minimal O-ring wear. For heavy stunts, the Kraton 6S is a better platform once you’ve upgraded the shock caps and swapped in stiffer springs. It’s the ideal mix if you’re always wrenching between sessions.
The Outcast 8S is for experienced bashers with a bigger budget and a dedicated wrenching bench. If you love sending huge jumps and don’t mind regular shock rebuilds (plus the cost of beefy spares), the Outcast is your canvas. Be ready to buy specialty tools and learn to spot a bent shaft by eyethis isn’t for the casual backyard driver.
For new owners, the Kraton 6S V5 BLX offers a good compromise between cost, durability, and upgrade paths. Its shocks are easily serviced, and common parts are widely available in 2026. The Mojave’s longer shocks are slightly more complex but reward you with smooth handling and less risk of cap blowout.
If your main terrain is pavement or hardpack, avoid going too thick on oilshock internals wear faster and you’ll see more leaks. For loose dirt and jumps, stiffer springs and alloy caps are mandatory upgrades. Avoid cheap eBay alloy caps; always use genuine ARRMA or reputable aftermarket (e.g., M2C Racing, Tekno O-rings for seal upgrades).
→ Metal Gear Servo, If your shocks are dialed but you’re still not tracking straight after big hits, a high-torque metal-gear servo keeps your steering precise and resists damage during hard landings.
Frequently Asked Questions
How often should I rebuild my ARRMA 6S shocks?
Rebuild your ARRMA 6S shocks every 10–15 full battery cycles for best performance. If you bash hard, land big jumps, or notice leaks, inspect them sooner. Regular rebuilds prevent bigger failures and extend the life of O-rings, shafts, and pistons under tough conditions.
What’s the best shock oil weight for Kraton 6S?
Stock oil is 1000cSt, but many bashers use 1200–1500cSt for larger jumps or rough terrain. Use lighter oil for more responsiveness on smooth tracks, and thicker oil for big-air landings. Don’t overfill the shock body, and always bleed air for consistent damping and durability.
Why do my Outcast 8S shocks keep bending shafts?
The Outcast 8S is heavy, and hard landings or rough jumps will bend even 6mm shafts. Upgrading to TiNi-coated shafts, avoiding bottom-out landings, and using quality pistons reduces the chance. Always check for micro-bends after each bashing session to prevent catastrophic failures.
Are alloy shock caps worth it for Kraton or Mojave?
Yes, alloy shock caps are crucial for the Kraton and Mojave 6S. They prevent cap blowouts, stripped threads, and ensure long-term reliability. Upgrading caps and regularly replacing O-rings greatly extends shock service life when bashing or sending big jumps.
Can I use Kraton 6S shocks on my Mojave?
Yes, Kraton and Mojave 6S shocks are interchangeable, but spring rates and lengths differ slightly. Always match the spring and oil setup to your truck’s needs. Alloy caps, O-rings, and piston upgrades cross over between both models for improved durability and performance.
What tools do I need for a shock rebuild?
You’ll need a hex driver set (2mm, 2.5mm, 3mm), shock pliers, a bleed tool, and a quality shock stand. Keep spare O-rings, a small bottle of cSt-rated shock oil, and some paper towels handy for clean assembly. Optional: calipers for checking shaft straightness after hard impacts.
Final Verdict: What Actually Works for ARRMA 6S/8S Shock Reliability?
If you’ve read this far, here’s the bottom line: factory ARRMA 6S and Outcast 8S shocks are capable, but only if maintained and upgraded intelligently. The Kraton 6S V5 BLX, with upgraded alloy caps, regular O-ring swaps, and the right oil, handles bashing and big jumps with little drama. Mojave 6S shines for fast desert rides and flowy tracks, needing fewer shock rebuilds if used as intended. The Outcast 8S, despite its sheer size, won’t tolerate neglect. Expect to rebuild shocks often, and invest in premium hardwareTiNi shafts, billet pistons, and quality O-ringsespecially if you’re sending it over 2 meters high.
For most hobbyists, a Kraton or Mojave with key upgrades is the best blend of durability and maintainability. If you love pushing limits or have a dedicated wrenching setup, the Outcast 8S rewards the extra effort with jaw-dropping stunts, at the cost of more frequent (and expensive) shock service. Remember, regular maintenance beats any single upgrade. Don’t wait for leaks or bottom-outs; keep your shock internals fresh and your bashing sessions will go longer, smoother, and way less frustrating.
Already upgraded your shocks and still seeing weird behavior? Check your servo, steering rack, and arm flex. Don’t ignore other weak points. And if you want to see how these shock lessons translate to smaller scales, check out our ARRMA Vorteks 3S upgrade article and our Mojave/Kraton suspension setup guide for more ideas. The ARRMA world is all about learning, wrenching, and actually running your RCs harddon’t let shock drama park your rig.
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