Upgrading the factory shocks on a Black Series HQ camper to Radflo remote reservoir shocks is one of the highest-value off-road upgrades you can make. The standard dampers that ship on the HQ19, HQ21 and similar models work fine on graded dirt, but they fade fast on washboard and heavily corrugated tracks. Heat builds up in the shock body, the oil thins, and damping drops off right when you need it most. Remote reservoir shocks move the oil and gas into a separate canister, add fluid capacity, and keep the damper cool over long, rough sections. This guide walks through a full bolt-on install you can do at home with hand tools in an afternoon.
What You Need Before You Start
This is a mechanical job, not an electrical one, so the tool list is short but you do need the right gear. Plan on having: a trolley jack rated for at least 2 tonnes, two axle stands, wheel chocks, a breaker bar, metric sockets (typically 17mm, 19mm, 22mm and 24mm for HQ running gear), a set of spanners to match, a torque wrench, anti-seize, and thread-locker. You will also want zip ties or billet reservoir clamps to mount the remote canisters, and a rubber mallet.
Before buying, confirm the shock length and mount style for your exact HQ model and axle setup. Black Series has run independent trailing-arm suspension on most HQ builds, but eye and stem mounts vary by year. Measure your extended and compressed shock lengths and the mount bore diameters, then match them to the Radflo part number. If you are unsure, send your VIN and a photo of the existing shock mounts to the parts team before ordering so you get the correct valving and length the first time.
Step 1: Lift, Support and Remove the Wheels
Park on level, hard ground and chock the wheels on the side you are not working on. Crack the wheel nuts loose before lifting. Raise one side of the trailer with the trolley jack under the chassis rail — not under the trailing arm or axle — and lower it onto an axle stand rated for the load. The suspension needs to hang free so the shock is at full droop, which takes tension off the mounting bolts. Remove the wheel and set it under the chassis as a backup safety catch.
Work one side at a time. Keeping one wheel and shock assembled gives you a reference if you need to compare orientation, hose routing or mount angle later.
Step 2: Remove the Factory Shock
Support the trailing arm with the trolley jack so it does not drop when the shock comes off. Spray penetrating oil on the upper and lower shock bolts and give it a few minutes. Remove the lower bolt first, then the upper. Black Series mounting hardware can seize, especially after dusty, wet trips, so use the breaker bar and keep steady pressure rather than shock-loading the fastener. If a bolt spins, hold the back nut with a spanner.
Once both bolts are out, compress the old shock by hand and lift it from the mounts. Inspect the mounting eyes and bushes while everything is apart — perished bushes or elongated bolt holes should be sorted now, not after the new shocks are torqued up. Clean the mount faces with a wire brush.
Step 3: Fit the Radflo Shock and Mount the Reservoir
Test-fit the new Radflo shock to confirm length and mount fit before committing. Install the upper mount first, sliding the bolt through with a smear of anti-seize on the shank (not the threads). Snug it by hand. Then raise or lower the trailing arm with the jack to line up the lower eye and slide the lower bolt through. Hand-tighten both, then check that the body and reservoir hose have clearance through the full range of suspension travel — cycle the arm up and down with the jack and watch the hose against the chassis, brake lines and tyre.
Now mount the remote reservoir. Choose a spot on the chassis rail or a frame member where the canister sits vertical or near-vertical, is protected from rock strikes, and keeps the hose away from sharp edges and heat sources. Use the supplied billet clamps for a clean, permanent mount; heavy-duty zip ties are acceptable only as a temporary measure. Route the hose with a gentle radius — no kinks, no tight bends — and leave enough slack for full droop. Secure it every 150–200mm so it cannot flap and chafe.
Step 4: Torque, Re-Check and Repeat
With everything aligned, torque the mounting bolts to the manufacturer's spec — for most HQ-class shock hardware this is in the 90–110 Nm range, but always use the figure Radflo or Black Series supplies for your mounts. Apply thread-locker to the bolts unless they use nyloc nuts. Do not over-torque; crushing a poly bush or bending a mount tab will ruin ride quality and can crack the shock eye.
Refit the wheel, torque the wheel nuts to spec, lower the trailer, and move to the other side. When both sides are done, roll the trailer forward and back a metre to settle the suspension, then re-check every shock and wheel fastener. After your first short trip — say 50km of mixed road and dirt — get under the trailer again and re-torque everything. Fresh installs commonly settle and lose a little clamp load on the first heat cycle.
Tuning and First-Trip Checks
Many Radflo remote reservoir shocks are adjustable. If yours have a compression adjuster on the reservoir, start in the middle of the range. Run a known corrugated track and adjust from there: more compression damping if the trailer feels floaty or bottoms out, less if the ride is harsh and skittish over small chatter. Make one change at a time and note it. Check the reservoir and shock body temperature by hand after a hard run — warm is normal, too hot to touch means the valving or pressure needs a look.
Inspect the hose routing again after the first proper off-road trip. You are looking for any rub marks, contact with the tyre at full lock or droop, and that every clamp is still tight. Catching a chafe point early is the difference between a five-minute re-route and a blown shock in the middle of nowhere.
The Practical Takeaway
Installing Radflo remote reservoir shocks on a Black Series HQ is a straightforward bolt-on job for anyone comfortable with a jack, axle stands and a torque wrench — budget an afternoon, work one side at a time, and never rush the wheel support or the torque specs. The payoff is consistent damping on long corrugations, far less fade, and a noticeably more controlled, comfortable tow on rough tracks. Get the length and valving right at the order stage, mount the reservoirs where they stay cool and protected, and re-torque after the first trip. Browse the full range of Radflo shocks and matching Black Series parts to spec the correct kit for your model.