--- title: "Dump Truck Bed and Hoist Repair | Rancho Santa Margarita" description: "Dump body and hoist repair on AR400 and Hardox beds: floor cracks at the front third, hinge point welds and cracked tailgate ears." focus_keyword: "dump truck bed and hoist repair rancho santa margarita" canonical: https://ocrv.me/vehicles/commercial-and-heavy/dump-truck-repair/ kind: vehicleType updated: 2026-07-29 source: OCRV Center --- # Dump Truck Bed, Hoist and Subframe Repair > A dump body wears from the **inside out and cracks from the front third back**. The expensive findings are always at the **hoist mount and the rear hinge**. ## What does dump truck bed and hoist repair involve? Dump truck repair covers abrasion resistant floors cracking at the sidewall seam, worn hoist trunnions and pin bores, cracked rear hinge and subframe mounts, tailgate hinge ears and latches, and cab shield damage. Rancho Santa Margarita and north county contractors bring these units to our Yorba Linda shop. - Loader drops crack the floor in the front third first - A body that leans going up has worn pin bores or a bent trunnion - Frame cracks near the hoist mount are the highest stress on the truck - No hot work happens on a body carrying asphalt or fuel residue ### Key facts | Item | Value | | --- | --- | | Chassis | 114SD, Peterbilt 348, T880, Mack Granite, International HV (GVWR 46,000 to 66,000 lb) | | Body material | AR400 or Hardox 450 floor (Lighter side sheet with horizontal and vertical bracing) | | Body builders | Ox Bodies, Godwin, Galion, Load King (10 to 16 foot bodies on a subframe with a rear hinge) | | Fabrication rate | $210 per hour (Structural welding on the posted body rate) | | Hinge and subframe band | $3,000 to $18,000+ (15 to 80 hours with the body supported and off the hoist) | Dump bodies are the only vehicle we work on that are deliberately abused as part of their function. Rock, broken concrete and hot asphalt get dropped into them from a loader bucket several feet above the floor, then dragged out over the tailgate sill. The material used is chosen for that: AR400 or Hardox 450 plate in the floor, which is hard enough to take the impact and hard enough to make repair a specialist job. What that means for an owner is that these trucks wear from the inside where nobody looks, and they crack in places that matter structurally. The hoist mount region is the highest stress area on the whole vehicle, the rear hinge carries the entire loaded body, and both of them fail with very little warning if the truck has been working a rock pit or a demolition job. ## AR400 wears from the inside where nobody looks Dump floors are abrasion resistant plate, usually AR400 or Hardox 450, chosen because it survives rock and broken concrete better than mild steel. It is also hard, which makes it stiff and less willing to bend before it cracks. And it wears from the inside surface, so a floor can lose a meaningful fraction of its thickness while looking entirely normal from underneath. We measure rather than guess. Ultrasonic thickness readings across the floor tell an owner what they actually have left, and that number decides whether the right answer is a repair, a wear plate overlay or a floor replacement. Guessing produces the worst outcome available: money spent welding a floor that was finished anyway. - AR400 and Hardox 450: hard, abrasion resistant, unforgiving of bad welding - Side sheet is softer than the floor, so the seam between them concentrates stress - Wear happens on the inside face and is invisible from below - Thickness readings turn a repair or replace argument into arithmetic ## Why the front third goes first Loader operators aim at the front of the body, so that is where material lands from height, load after load. The energy goes into the floor and then into the seam where hard floor plate meets softer side sheet. Combine impact loading with a floor that has thinned from wear and the crack appears at the seam, usually within the first third of the body length. Repairing it properly means welding procedures suited to abrasion resistant plate, with preheat where the material and thickness call for it, and stopping the crack before welding rather than running a bead along it. Done wrong, the heat affected zone becomes the next crack. This is a category where the difference between a good and a poor weld shows up within months. ## A body that leans on the way up The hoist lifts through pins in trunnion mounts, and grit plus load makes those bores go oval. When one side develops more clearance than the other, the body tracks off centre as it rises and the hinge and subframe have to fight the difference. Drivers report it as a lean, and it is almost always the mounting rather than the cylinder. We inspect with the body down and supported: pin and bore condition, trunnion alignment, mount weld condition, and whether the subframe has moved. Bores get rebuilt with new bushings and pins to specification. Ignoring a lean is how a mounting problem becomes a subframe repair, and the subframe repair costs several times as much. 1. Lower the body and support it on rated stands 2. Measure pin and bore wear at both trunnion mounts 3. Check mount welds and subframe alignment before ordering parts 4. Rebuild bores and fit new pins and bushings to specification 5. Cycle the body empty, then loaded, and check tracking both ways ## The rear hinge and the highest stressed part of the truck Every time the body tips, the entire loaded weight passes through the rear hinge assembly and into the subframe. Do that on a slope, or with the truck sitting out of level in a jobsite yard, and you add a twist the hinge was never designed to take. Cracks start at the hinge ears, run into the subframe rail, and in bad cases reach the chassis frame near the hoist mount. That region is the highest stress area on the whole vehicle, so repairs there are done with the body supported and off the hoist, with proper preparation, and with reinforcement placed so it does not create a new stress riser at its own edge. We also check the chassis rails while we are in there, because a subframe crack often has a chassis crack keeping it company. > **warning:** Never inspect or work under a raised dump body without the body prop engaged and stands in place. Hydraulics hold a body up until they do not, and this is the one item on this page that has killed people. ## Tailgates, trickle and citations A tailgate hangs on upper pins, takes the load pressing against it for the whole trip, and gets hammered by material on every dump. Ears crack at the weld and latch components wear until the gate cannot pull tight. Then aggregate trickles out on the road, which turns into a citation and a complaint long before it becomes a repair order. We rebuild ears with proper preparation and reinforcement, replace worn pins and latch hardware, and set the gate so it seals along its full width. Setting a gate on worn ears is pointless, because the geometry is already wrong. The whole assembly gets addressed together or the trickle comes back. ## Loader strikes on the cab shield and hood The most common actual collision damage on a working dump truck comes from the machine loading it. A bucket clips the cab shield and folds it toward the cab roof, or comes across the hood and takes the hood, a mirror arm and the stack shield with it. It happens in seconds during a routine load and it is nobody's finest moment. These repairs are straightforward and the important part is documentation. Photograph the damage with the machine visible if you can, because a loader strike is a liability claim against the equipment owner rather than a hit on your own physical damage policy. Contractors who take those photographs recover the money. ## Hot work rules, rates and scheduling Two rules govern every dump job here. Nobody works under a body that is not supported on stands with the prop engaged, and no arc is struck on a body carrying asphalt, fuel or oil residue until it has been cleaned, with a fire watch during any hot work. Both cost a little time and neither is negotiable. Structural welding and fabrication bill at $210 per hour. Deposits start at fifty percent above $2,000 and a further twenty five percent applies at parts arrival above $10,000, which covers most hinge and subframe work. A written estimate is $150, credited in full against an authorized repair, and it includes floor thickness readings when a floor is in question. Everything is in shop at Yorba Linda, and this is not a mobile service. ## Questions and answers ### Why does my dump body crack at the seam near the front? Because that is where the loader aims and where hard floor plate meets softer side sheet. Material dropped from height puts impact energy into that seam, and a floor thinned by wear from the inside has less left to absorb it. We stop the crack before welding and use procedures suited to abrasion resistant plate. ### My dump body leans to one side as it raises. What is wrong? Usually worn pin bores at the trunnion mounts rather than a bad cylinder. Grit and load make those bores go oval, and once one side has more clearance the body tracks off centre and the hinge fights the difference. We measure both bores with the body supported and rebuild them with new pins and bushings. ### How serious is a crack at the rear hinge of a dump body? Serious. The entire loaded body weight passes through that hinge every tip, and cracks there travel into the subframe and sometimes into the chassis rail near the hoist mount. Repair happens with the body supported and off the hoist, with reinforcement placed so it does not create a new stress riser at its edge. ### How do I know whether a dump floor is worth repairing? Measure it. Ultrasonic thickness readings across the floor show what is actually left, since AR plate wears from the inside face and looks fine from below. That number decides between crack repair, a wear plate overlay or a full floor replacement. We include the readings in the written estimate so the decision is arithmetic. ### Material trickles from my tailgate on the road. What fixes that? The whole assembly, not just the latch. Ears crack at the weld and latch hardware wears until the gate cannot pull tight along its width. Setting a gate on worn ears is pointless because the geometry is already off. We rebuild ears with reinforcement, replace pins and latch parts, then set the gate to seal full width. ### Can you weld a dump body that has been hauling hot asphalt? Only after it is cleaned. Asphalt, oil and fuel residue near an arc is an unacceptable fire risk, so the body is cleaned and cleared first and a fire watch stands by during hot work. Nobody works under the body either unless it is on rated stands with the prop engaged. Both steps cost time and neither is optional. --- Source: [OCRV Center](https://ocrv.me/vehicles/commercial-and-heavy/dump-truck-repair/). Last verified 2026-07-29.