Trailers Repair for West Covina

How a bumper pull trailer carries its load and where that load breaks things

A conventional trailer does not put its weight over the tow vehicle's rear axle. It hangs ten to fifteen percent of its loaded weight off a coupler that sits well behind the bumper, at the point where two steel A frame members converge. That tongue is the longest lever on the vehicle. Every input from the road, every brake application, every gust off the 60 near the Kellogg interchange travels through it and into the front crossmember.

The single most common structural repair we write on a towable is a bent A frame, and it almost never happens at speed. It happens in a driveway or a storage lot at walking pace. The driver backs, the trailer folds toward the truck, the front corner of the trailer meets the bedside, and the tongue takes a permanent set. Owners describe what follows as the trailer tracking funny, wandering under braking, or pulling one direction on a level road. What they are describing is a coupler that is no longer sitting on the trailer's centerline.

Sway is the second load case, and it works the tongue differently. A weight distributing hitch loads the spring bars against brackets clamped to the A frame rails. Those brackets are a stress concentration. When they are overtightened, misplaced or left on a rail that has already been tweaked, they mark the steel, and cracks start under the bracket where nobody looks. On any structural evaluation we pull the hitch hardware off and inspect the rail underneath it before we look anywhere else.

• A bent A frame usually comes from a low speed jackknife, not a highway crash
• A coupler off centerline makes the trailer track and brake unevenly
• Weight distribution bracket clamps hide cracking in the A frame rails
• Cracked welds at the tongue to crossmember joint are the classic follow on failure
• A trailer that suddenly needs constant steering correction should be measured, not just realigned

Azdel or luan: knowing what is behind your sidewall before the repair starts

Nearly every laminated trailer built in the last three decades uses the same sandwich. An exterior skin of gel coated fiberglass or filon, a substrate board bonded to the back of it, aluminum tube framing with block foam filling the bays, and an interior finish panel. The skin carries almost no load by itself. The strength comes from the bond between the layers, and the substrate is the layer that decides whether water is an inconvenience or a rebuild.

Luan is a thin tropical plywood. It is light, it takes adhesive well and it is what most trailers used for decades. It also wicks water along the grain, swells, delaminates from the skin and eventually goes to a black pulp that has no structure left. Azdel is a polypropylene and fiberglass composite board. It does not rot and it does not wick, which is a real advantage, but the adhesive bond to the skin still fails when water sits in it. The difference is that an azdel wall hides the problem longer, because there is no swelling to push a bubble out at you.

We identify the substrate before quoting a wall repair. The reliable method is to look at a cut edge, usually where a window, a vent or a marker light comes out. Luan shows the layered edge of plywood and darkens where it has been wet. Azdel shows a uniform gray fibrous board with no grain. That one observation changes the scope. On luan, the wet substrate is cut out and replaced. On azdel, a large percentage of walls can be dried, cleaned back to sound adhesive and rebonded, which is a shorter job.

• Laminated wall: skin, substrate, aluminum framing, block foam, interior panel
• Luan swells and rots, and it pushes a visible bubble as it fails
• Azdel does not rot but the skin still releases where water sits
• A cut edge at a window or vent opening tells you which you have
• Substrate type changes whether a wall gets replaced or rebonded

Where water gets into a trailer, seam by seam

A trailer is a box made of panels that were sealed at the factory and then driven through weather at highway speed for years. The seams fail in a predictable order in Southern California, and the order is set by ultraviolet exposure rather than by rainfall. Sealant here dies of sun long before it dies of water, which is why owners in West Covina often find a stain during the first real storm after two dry seasons of quiet degradation.

The roof to sidewall seam is the one that costs the most money. On most towables it is a screwed on aluminum or vinyl insert molding with a bead of sealant behind and above it. When that bead shrinks, water gets behind the molding, runs down inside the wall cavity and shows up as a stain at the ceiling to wall corner, or as softness low on the wall where gravity finally stopped it. The molding itself still looks fine from the ground, which is why owners miss it.

Corner molding on the vertical seams is next, followed by window frames where the butyl tape has hardened and squeezed out, the front rock guard mounts, the marker light gaskets, the ladder mounting plates and every roof penetration. Roof work uses two different products for a reason. Self leveling lap sealant flows out flat and belongs on horizontal surfaces like the area around a vent or an air conditioner. Non sag sealant belongs on vertical seams and on the sidewall side of the roof edge, because self leveling material will run and leave the top of the seam thin. Eternabond tape has a place, but it is a repair rather than a maintenance product, and burying an unresolved leak under tape only means paying for substrate later.

• Roof to sidewall seam is the most expensive leak on a towable trailer
• Corner molding, window butyl and marker light gaskets follow close behind
• Self leveling sealant for horizontal seams, non sag for vertical
• Sun ages sealant faster here than water reveals the damage
• Sealing over old material buries the evidence instead of fixing the leak

Axle over, axle under and what the suspension does to the frame

Most towable trailers ride on leaf sprung Dexter, AL-KO or Lippert axles hung from welded hangers with an equalizer between them on tandem setups. Whether the axle sits above or below the springs is not a detail. Spring over axle raises the trailer, gives more ground clearance and is common on off road and taller units. Spring under axle lowers it and is standard on most travel trailers. Owners who lift a trailer by flipping the axles change ride height, tongue angle and the leverage the suspension applies to the hangers, and we regularly see cracked hanger welds on trailers that were flipped without reinforcing the mounts.

The wear items underneath tell a story before anything cracks. Shackle bolts and bushings wallow. Equalizers wear at their center bushing and stop sharing load between the two axles, which means one axle carries more than it should and its hangers see more cycles. Wet bolts and greaseable shackles slow that down but do not stop it. When we do a structural evaluation we measure axle to axle spacing side to side, look for a bowed axle tube, check for uneven tire wear patterns and inspect every hanger weld toe with the trailer supported.

The other suspension related structural finding is a frame that has taken a set. Overloading a trailer, or loading it with all the weight behind the axles, bends the rails between the axles and the rear bumper. It shows as a rear end that sits low, a rear bumper closer to the ground on one side, or interior doors that suddenly bind at the top. Correction means supporting the frame, measuring it, pulling it back and then reinforcing so it stays there. We handle suspension, hanger and frame work on the trailer. We do not perform engine or drivetrain work on the tow vehicle.

Slide openings, frame flex and the interior symptoms owners notice first

Cutting a slide opening into the sidewall of a towable removes a large section of the structure that was resisting twist. Manufacturers compensate with a heavier header and reinforced posts, but a trailer with a large slide is measurably less stiff than the same trailer without one. Drive it over enough uneven pavement and the opening works. That working shows up in three places: at the corners of the opening, at the floor where the slide rails pass through, and at the outriggers directly under the room.

Owners rarely notice a frame problem from underneath. They notice it inside. A bathroom door that used to close now needs a lift. A drawer that stays shut on the road starts sliding open. The slide seals flat on one end and leaves a wedge of daylight at the other. Cabinet doors at the far end of the coach stop lining up. Those symptoms mean the body has moved, and the correct response is measurement rather than adjusting a latch.

Slide mechanisms on towables are usually Schwintek In Wall rail drives on smaller rooms, cable systems such as BAL Accu Slide on mid size rooms, or a rack and pinion through frame system on larger ones. Each has a different signature when a room is fighting an opening that has moved. Rail drives lose sync and rack. Cable systems go slack on one side. Rack and pinion units chatter and stall. In all three cases, forcing the room does more damage to the opening than the original problem did, so stop cycling it and call.

• Doors that suddenly bind are a structural symptom, not a hardware symptom
• Slide opening corners and the outriggers under the room are the inspection points
• Schwintek racks, cable systems go slack, rack and pinion units chatter
• Forcing a slide that is fighting a moved opening multiplies the repair

Bringing a trailer from West Covina to the Yorba Linda shop

OCRV Center is at 23281 La Palma Ave in Yorba Linda. It is not in West Covina. We serve West Covina from Yorba Linda, and the drive is about 22 miles and 30 to 45 minutes on a normal day. Most owners take the 10 or the 60 west to the 57 south, then the 91 east to Imperial Highway. When the 57 stacks up through Brea, Carbon Canyon Road across to the 71 is the local alternative and it tows comfortably.

Before you hook up, check the tire date codes. Trailer tires in this climate age out of service long before they wear out, and a sidewall that has been baking on a driveway in Sunset Hills for six summers can let go on a hot afternoon on the 57. Check the coupler latch and the safety chains, verify the breakaway cable and battery, and confirm the brakes engage from the controller before you leave the neighborhood. If the tongue is bent or a hanger weld is cracked, send photos first and let the estimator tell you whether it should come in on a transport. All of our work is performed in the building at Yorba Linda and we do not offer mobile service.

For insurance work, bring the claim number and the adjuster's contact information. Collision estimates are written at the shop with the trailer in front of us, and insurance walk ins are welcome during business hours: Monday through Friday 8:00 AM to 5:00 PM and Saturday 9:30 AM to 3:00 PM. Estimates on slides, water systems, electrical and appliances carry a diagnostic charge that is credited against authorized repair work. Call (949) 799-3387 to get on the schedule before you make the drive.