--- title: "Fifth Wheels Repair in West Covina" description: "Structural, fiberglass, slide and refinish repair for fifth wheels of every length, handled in shop in Yorba Linda for West Covina owners." canonical: https://ocrv.xyz/vehicles/fifth-wheels/ business: "OCRV Center" phone: "(949) 799-3387" address: "23281 La Palma Ave, Yorba Linda, CA 92887" market_served: "West Covina, California" --- # Fifth Wheels Repair in West Covina A fifth wheel carries its load through the pin box into the truck bed, so damage shows up at the front first: cracked king pin welds, an opening crown seam, a soft upper deck floor. OCRV Center repairs structure, fiberglass, slides and paint on fifth wheels for West Covina owners at our Yorba Linda shop. ## Why fifth wheel damage almost always starts at the front A travel trailer hangs its tongue weight off a ball at the bumper. A fifth wheel does something very different. It puts fifteen to twenty five percent of its total weight directly over the truck's rear axle through a king pin that is welded into a pin box, and that pin box is bolted or welded to the leading end of the frame. Every acceleration, every stab of the brakes, every dip in the pavement on Amar Road loads that one joint. Because the load path is concentrated, the failures are concentrated too. We see hairline cracks radiating from the pin box gussets, elongated bolt holes where a bolted pin box has been working against the frame, fiberglass stress marks on the underside of the upper deck, and interior cabinet doors in the bedroom that stop latching because the front of the coach has flexed a fraction of an inch out of square. The second reason the front takes the beating is geometry. The overhang above the truck bed is a cantilever. It is unsupported, it is the tallest part of the coach, and it takes the full force of headwind and of anything the truck kicks up. Rock chips, cap crazing, seam separation at the crown and delamination on the front wall are all products of that exposure. - Cracks radiating from pin box gussets and welded attachment plates - Elongated or wallowed bolt holes on adjustable pin boxes - Fiberglass stress crazing at the underside radius of the overhang - Cabinet and door latches that stop lining up after a hard tow - Front cap crown seam sealant that has shrunk and pulled away ## Pin box, king pin and the hitch interface we inspect first Every fifth wheel that comes into the Yorba Linda shop for structural evaluation gets the pin box pulled into the light before anything else. We look at the weld toes where the box meets the frame, the gusset plates, the jaw contact wear on the king pin itself, and whether the skid plate is scored in a pattern that suggests the hitch height was wrong. A king pin that has been running low grinds a bright arc into the skid plate and puts a bending load into the box that it was never designed to carry. Air ride and rubber isolated pin boxes such as the Lippert Trailair and the Reese Sidewinder change the failure mode. They are excellent at taking chucking out of the ride, but they add moving parts and a longer lever arm. When the bushings wear or an air bag loses pressure, the box starts to knock, and that knocking transfers straight into the leading crossmember. Owners describe it as a bang from the front of the trailer when they let off the throttle. Repair depends on what is cracked. Surface cracking in a gusset gets ground out, veed and rewelded with the correct process for the base metal, then gusseted properly. A cracked or distorted pin box gets replaced with the correct rated unit rather than patched, because the pin box is the single component holding the front of your trailer to the truck. When the frame itself has torn at the attachment, the repair moves into frame and structural work and the front section gets supported and re squared before any welding happens. ## Front cap crown seam, delamination and the upper deck floor The crown seam is the joint that runs across the top of the front cap where the molded fiberglass cap meets the roof membrane. It is sealed at the factory with a lap bead over a screw line or a molded trim, and it is the single most common water entry point on a fifth wheel. The bead shrinks under Southern California ultraviolet load, opens a hairline gap, and water follows the wind straight into the joint at towing speed rather than dripping harmlessly off the front. Once water is in that seam it has two paths. It can travel down the inside face of the front cap, where it soaks the luan or the block foam behind the fiberglass and produces the bubble that owners find when the sun heats the front wall in the afternoon. Or it can run rearward along the top of the upper deck floor, which is the part that sits over the truck bed, and rot the decking from underneath while the carpet on top still looks new. The way to check the upper deck yourself is to walk it barefoot and slowly. A healthy deck feels uniform. A compromised one has a spongy patch that usually shows up first near the front corners or under the head of the bed where the platform hides it. If the deck moves under your weight, the repair is structural: the flooring gets opened, wet substrate and any rotted framing gets cut out, new material is scarfed in and bonded, and the fiberglass skin gets reset and refinished so the repair does not print through the paint. - Hairline opening at the crown seam is the most common water entry on a fifth wheel - Front wall bubbling is delamination, not a paint defect - A soft upper deck near the bed platform usually means the crown seam failed seasons ago - Interior carpet can look perfect while the substrate under it is gone ## Slide rooms on a fifth wheel: Schwintek, Accu Slide and hydraulic Fifth wheels run more slide rooms than any other RV type, and the mechanism under each one determines both how it fails and what a repair costs. Schwintek In Wall systems drive the room from vertical rails in the side walls with two synchronized motors. When one motor loses count or one rail binds, the room racks: it comes in or goes out with one end ahead of the other, the gear teeth chatter, and if you keep cycling it the rack strips and the wall gets damaged where the room jams. BAL Accu Slide runs a cable and pulley system under the floor. Its symptom set is different. Cables stretch and fray, the take up drum loses tension, and the room stops sealing flat against the wall on one side. Hydraulic rams, common on the large living room and kitchen slides in heavier coaches, are strong and quiet until a seal weeps, the pump loses prime, or a hose chafes through against a crossmember and dumps fluid on the driveway. Above the mechanism sits the seal package, and seals cause more water damage on fifth wheels than mechanisms do. The bulb seal on the outside face takes a compression set after a few seasons parked, and once it stops rebounding it lets water track down the wall cavity instead of shedding it. Wiper seals harden and tear at the corners. A slide out repair done properly resets the room square, sets sweep and travel, replaces both bulb and wipers, and verifies that the room seals evenly top to bottom before it goes back out. ## Lippert frame welds, landing gear and the running gear underneath Most fifth wheels built in the last twenty years ride on a Lippert chassis, and the chassis is built from formed steel channel with welded crossmembers and outriggers. The welds we find cracked are rarely random. They are at the transition where the frame steps up over the axles, at the outrigger to rail joint under a heavy slide, and at the leading crossmember where the pin box loads it. Cracks there tend to announce themselves as new rattles and as doors that suddenly need a shoulder to close. Landing gear takes its own kind of abuse. A leg that has been extended onto soft ground, or dropped onto an uneven pad and then loaded, bends at the inner tube and starts to bind. Owners hear the motor labor and then hear it stall. Sometimes the leg is straight and the problem is the cross shaft, the gearbox or a corroded ground on the motor. Sometimes the leg is genuinely bent and it gets replaced along with the mount plate that pulled at its welds. Underneath, we check spring hangers, equalizers, shackle bolts and wet bolts on every structural evaluation. A worn equalizer on a triple axle rig puts unequal load into the frame and can be the actual cause of a crack you were about to attribute to the pin box. Dexter and Lippert axle assemblies are both common on these coaches. We handle the suspension, hanger and structural side of that work. We do not do engine or drivetrain work on the tow vehicle. - Frame cracks concentrate at the step up over the axles and under heavy slides - A bent landing gear inner tube binds long before it refuses to move - Worn equalizers and shackle bushings load the frame unevenly - Outrigger welds under a full wall slide are a routine inspection point ## Roof, sidewall seams and the sealant schedule that actually works Fifth wheels present a lot of horizontal surface. A forty foot coach can carry a hundred and forty square feet of roof membrane with two air conditioners, a vent fan, a refrigerator vent, an antenna, a solar array and a plumbing stack punched through it. Every one of those is a seam, and on an EPDM or TPO membrane every seam is held by a self leveling lap sealant that has a service life measured in a handful of Southern California summers, not in decades. The three seams that matter most on this vehicle type are the crown at the front cap, the roof to sidewall joint along both sides, and the rear cap radius. The roof to sidewall joint hides under a screwed on molding with a bead behind it. When that bead shrinks, water gets behind the molding, tracks down inside the wall, and the first visible symptom is a stain at the ceiling to wall corner in the bedroom or a soft spot at the base of a slide opening. Corner molding on the vertical seams is the same story with gravity working against you. Owners who reseal on a schedule are the ones whose coaches stay dry. Owners who wait until they see a stain are already paying for substrate. When we reseal at the shop the old material comes off rather than getting buried under a fresh bead, the substrate gets inspected while it is open, and the new sealant is matched to the membrane type so it bonds instead of peeling in sheets the following summer. ## Towing a fifth wheel 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, and we say that plainly because the drive matters when you are moving a damaged forty foot trailer. Plan on roughly 22 miles and 30 to 45 minutes. Most owners run the 10 or the 60 west to the 57 south, then take the 91 east to Imperial Highway. When the 57 stacks up through Brea, Carbon Canyon Road across to the 71 is the local shortcut and it is comfortable with a long fifth wheel behind you. If the damage is structural at the front, do not tow it yourself. A cracked pin box or a torn leading crossmember can let go under load, and the failure mode is the trailer coming down on the truck bed. Send us photos of the pin box, the underside of the overhang and the frame at the front, and we will tell you whether it should come in on a transport instead. Arranging that transport is on the owner. All of our work is performed in shop at Yorba Linda and we do not offer mobile service. Bring the trailer with the bays cleared of anything you need in the next few weeks, with the propane bottles at whatever level they are, and with the slides retracted unless we have asked otherwise. Bring your insurance claim number if there is one, along with the adjuster's contact information. Estimates on collision damage are written at the shop with the vehicle in front of us. Call (949) 799-3387 to get on the schedule before you make the drive. ## Frequently asked questions ### Can a cracked pin box be repaired, or does the whole thing have to be replaced? It depends on where the crack is. Surface cracking in a gusset or a bracket can be ground out, veed, rewelded with the correct process and reinforced. Cracking through the box structure itself, a distorted box, or wallowed mounting holes means replacement with a correctly rated unit. We do not patch a pin box that is carrying a bending load, because that single joint holds the front of your trailer onto the truck. When the frame has torn at the attachment, the front gets supported and re squared before any welding starts. ### How can I tell whether my fifth wheel upper deck floor is going soft? Walk it slowly in socks or bare feet, especially near the front corners and under the bed platform where damage hides. A healthy deck feels uniform underfoot. A failing one has a patch that gives slightly, sometimes with a faint crackle. Also look at the ceiling to wall corner in the bedroom for staining and press the front wall with your palm for softness or bubbling. If any of that is present, the crown seam has probably been open for a while and the repair is structural rather than cosmetic. ### My Schwintek slide grinds and comes in crooked. What is going on? That is the classic loss of sync. Schwintek drives the room from two motors on vertical rails, and if one side loses count or one rail binds, the room racks out of square. The grinding you hear is gear teeth skipping on the rack. Stop cycling it. Every additional attempt strips more teeth and can damage the wall opening where the room jams. The repair involves resetting the room square, checking rail alignment and fasteners, replacing damaged racks or gear packs, and resyncing the controller. ### Do you handle fifth wheel damage through an insurance claim? Yes. Collision, hail, tree limb, awning tear away, hitch failure and storage lot impact claims are a large part of what comes through the shop. We write the estimate at Yorba Linda with the trailer in front of us, document the damage photographically, and work directly with the carrier and the adjuster through supplements. Bring the claim number and the adjuster's contact information to the appointment. Insurance walk ins are welcome during shop hours. ### How long does front cap work take on a fifth wheel? A crown seam reseal with no substrate damage is a short visit. A front cap that needs fiberglass repair, delamination correction and refinishing is a multi week job, and the reason is paint rather than glass. Molded caps carry a graphics package and a clear coat, and blending a repair into an existing gel coat or painted cap takes cure time between stages. Full cap replacement adds lead time for the part itself, which is ordered to the model and year. ### What do I need to bring when I drop a fifth wheel off in Yorba Linda? Bring the trailer with personal belongings cleared out of the areas we will be working in, the bays emptied of anything you will need soon, and any keys for compartment locks. Bring the insurance claim number and adjuster contact if a claim is open, plus photos of the damage as it first appeared. If the coach has aftermarket solar, an inverter or an upgraded pin box, tell the estimator, because those change how we support and disassemble the vehicle. --- OCRV Center, 23281 La Palma Ave, Yorba Linda, CA 92887. Phone (949) 799-3387. All work is performed in shop at the Yorba Linda facility. We do not run mobile, roadside or fleet route service. Ranges are planning figures, not a quote. Final numbers come from a written estimate on your vehicle.