--- title: "Custom Converted RV Repair | Rancho Santa Margarita" description: "Owner built and one off RV conversion repair in Yorba Linda: undocumented wiring, house to frame mounting, non certified LP installs and box body structure." focus_keyword: "custom converted rv repair rancho santa margarita" canonical: https://ocrv.me/vehicles/rvs-and-motorhomes/custom-converted-rv-repair/ kind: vehicleType updated: 2026-07-29 source: OCRV Center --- # Custom Converted RV Repair for Owner Built Coaches > A one off conversion has **no build sheet and no RVIA seal**, so every repair starts with reverse engineering. The **house to frame mounting** and the undocumented wiring are where the real risk sits. ## Can a custom converted RV be professionally repaired? Yes. Custom conversion repair means documenting what the builder actually did, then repairing to a standard. Our Yorba Linda shop handles box truck and toterhome conversions for Rancho Santa Margarita owners, covering house to frame mounting, undocumented wiring and structure that was never engineered as an RV. - There is no build sheet, so the first job is mapping the build - House to frame mounting is the most common structural shortcut - Wiring follows whoever did it, not a published standard - Insurance classification is often the owner's biggest exposure ### Key facts | Item | Value | | --- | --- | | Base vehicles | Box truck, toterhome, stripped chassis (Freightliner, International, Isuzu and Ford medium duty are the common donors) | | Certification | No RVIA seal (No build sheet, no certified LP install and no published twelve volt standard) | | First step | Documented build map (Diagnostics at $285 per hour, one hour minimum, credited against an authorized repair) | | Common shortcut | House bolted or U bolted to frame (Rigid mounting to a frame that flexes, with no isolation) | | Structural rate | $210 per hour (Electrical and systems work at $260 per hour) | Custom conversions arrive in every possible condition. Some are better engineered than anything a production plant ships, built by someone who understood load paths and wire gauge and did the work properly. Others are a plywood box screwed to a truck frame with lamp cord running through it. The two look similar in a photograph and nothing about repairing them is the same. What they share is the absence of documentation. There is no build sheet, no RVIA seal, no certified LP install record and no wiring diagram, so the first hour of any job on a conversion is spent establishing what is actually there rather than repairing anything. ## The first deliverable is a map, not a repair On a factory coach we look up a schematic. On a conversion there is nothing to look up, so we build the document ourselves: where the shore inlet lands, what feeds the panel, how the house ground is established, which circuits are shared with the chassis, where LP runs and how it is penetrated, and how the box is attached to the frame. That is billed as diagnostics at $285 per hour with a one hour minimum, credited in full against an authorized repair. Owners occasionally resist paying for information rather than parts. In practice it is the least expensive hour on the job, because every alternative involves opening panels speculatively and guessing at gauge and grounding. - Trace and label every house circuit back to its source - Identify shared chassis and house grounds - Locate and photograph LP routing and penetrations - Establish how and where the box attaches to the rails ## How the box is attached is the structural question This is the single most common serious defect we find. A commercial truck frame is a flexible structure by design. Bolt a rigid living box down hard to the rails and the box becomes part of the frame's torsional path, which it is not built to be. The result is a split at a wall to floor corner, usually just behind the cab where the twist is highest. Correcting it means introducing compliance: a subframe, isolation mounts, or a mounting pattern that allows relative movement while still restraining the box. That is fabrication work rather than a repair, and it is the difference between fixing the crack and stopping the crack from coming back. > **warning:** A crack behind the cab at a wall to floor corner on a conversion is a mounting problem, not a panel problem. Repairing the panel alone guarantees a repeat. ## Undocumented wiring and shared grounds The signature fault on a conversion is an interaction: a light dims when the pump runs, an inverter faults when the engine starts, a fridge trips only on shore power. Those are grounding and gauge problems, and they are invisible if you test one circuit at a time. They only appear when the system is mapped as a whole. We separate chassis and house grounds properly, size runs for the actual load rather than the connector that happened to be available, and rebuild the distribution panel with labelling that the next technician can read. Electrical work bills at $260 per hour, and on a conversion the honest majority of the first visit is tracing rather than replacing. ## What we will not do on a conversion We will not return a vehicle with an LP installation we know is unsafe, and we will not repair around one. If the propane routing is unprotected through a penetration, or a fixed appliance is unvented, that gets corrected or the appliance gets disconnected. There is no version of this where we hand back keys and mention it in a note. We also will not certify a conversion as RVIA compliant, because that is not something a repair facility can confer. What we can do is document what was corrected, to what standard, with photographs, which is genuinely useful to an owner talking to a carrier or a buyer later. ## Rates and how a conversion estimate is built Structural, body and fabrication work bills at $210 per hour with body supplies at $5 per body hour. Electrical, plumbing and appliance work is $260 per hour. Diagnostics and mapping are $285 per hour with a one hour minimum. A written estimate is $150, credited in full against an authorized repair. Conversion estimates carry more teardown and access time than factory coach estimates, and we show it as its own line. That is not padding. On a unit where the water heater may be behind a bonded panel and the panel may be behind a bed platform, reaching the component is frequently the majority of the job. ## Who owns conversions and what they usually need Two patterns. Owners who built the vehicle themselves and have hit something outside their skill set, usually structural or LP related, and who are generally excellent to work with because they know the build intimately. And second owners who bought somebody else's project and inherited decisions they cannot see. The second group needs the mapping document more than the repair. We have had Rancho Santa Margarita owners arrive with a chased electrical fault and leave with a labelled panel, a corrected ground and a document, which then made every subsequent job on the vehicle cheaper. ## Questions and answers ### Why do I have to pay for diagnostics before you fix my conversion? Because there is nothing to look up. A factory coach has a schematic and a service manual. Your vehicle has whatever the builder did, unlabelled, so the first hour produces the map that every later decision rests on. It bills at $285 per hour and credits in full against an authorized repair. ### My conversion has split at a corner just behind the cab. What caused it? Rigid mounting. Truck frames twist by design, and if the living box is bolted straight to the rails it becomes part of that torsional path. The highest twist is just behind the cab, so a wall to floor corner splits there. Fixing the panel without adding compliance to the mounting guarantees it returns. ### A light dims whenever my water pump runs. Is that dangerous? It is a symptom worth chasing. Interaction faults like that are usually a shared ground or an undersized run rather than a failing component, and they stay invisible if you test circuits individually. We map the whole system, separate chassis and house grounds, and size runs for the real load. ### Will you work around a propane install you think is unsafe? No. If LP is routed unprotected through a penetration or a fixed appliance is unvented, it gets corrected or the appliance gets disconnected before the vehicle leaves. We will not repair adjacent to a hazard and mention it in a note, and we say this at the estimate stage rather than at pickup. ### How should a home built RV conversion be insured? Get the classification confirmed in writing. Many carriers write conversions as commercial trucks, which values the chassis and ignores the living space, so a loss pays out on a box truck. Photograph and inventory the build now, because there is no build sheet or MSRP anyone can reference later. --- Source: [OCRV Center](https://ocrv.me/vehicles/rvs-and-motorhomes/custom-converted-rv-repair/). Last verified 2026-07-29.