--- title: "Vintage and Classic RV Repair | Rancho Santa Margarita" description: "Riveted aluminum and stick and tin coach restoration in Yorba Linda: belt rail rot, elongated rivet holes, butyl bedded seams and fabricated obsolete panels." focus_keyword: "vintage and classic rv repair rancho santa margarita" canonical: https://ocrv.me/vehicles/rvs-and-motorhomes/vintage-classic-rv-repair/ kind: vehicleType updated: 2026-07-29 source: OCRV Center --- # Vintage and Classic RV Repair, Riveted and Stick Built Coaches > Coaches built before the laminated era use **aluminum skin over a timber or steel skeleton**, bedded in butyl and riveted. Restoration lives at the **belt rail and the rivet line**, and most panels have to be made. ## How is vintage RV repair different from modern coach repair? Vintage coach work means riveted aluminum or stick and tin construction over timber or steel framing, bedded in butyl rather than bonded. Rancho Santa Margarita owners bring GMC motorhomes, Argosys and seventies era coaches to Yorba Linda, where obsolete panels are fabricated rather than ordered. - No Azdel, no vacuum bonded laminate and no molded caps - Rivet holes elongate over decades and stop sealing - The belt rail is the usual rot line on a wood framed coach - Most exterior parts no longer exist and get made here ### Key facts | Item | Value | | --- | --- | | Construction era | 1950s to mid 1980s (Aluminum sheet over timber or steel skeleton, butyl bedded seams, riveted or screwed) | | Panel sourcing | Fabricated in house (Welding and metal fabrication department, no supplier catalogue for these parts) | | Usual rot line | The belt rail (Where the sidewall sheet laps the lower body and water has run for decades) | | Fabrication rate | $210 per hour (Same department and rate as body and structural work) | | Assessment | $285 per hour (One hour minimum, credited in full against an authorized repair) | Everything that makes a modern coach predictable is absent here. There is no Azdel substrate, no vacuum bonded sidewall, no molded fiberglass cap and no EPDM membrane. A coach from 1974 is aluminum sheet fastened over a skeleton of timber or steel, with the seams bedded in butyl tape and closed with rivets or screws, and a roof that is more of the same material. That construction is repairable almost indefinitely, which is why these coaches are still on the road. It is also labor intensive, because the parts catalogue closed decades ago and the correct repair for a corroded panel is usually to make a new one on the brake and the shear. ## Bedded and riveted, not bonded Modern coach seams are adhesive joints. Vintage coach seams are mechanical joints with a compressible sealant between them, which is a fundamentally different thing. A lap seam on a 1972 coach works because a strip of butyl tape is being squeezed between two sheets by a row of rivets or screws, and it keeps working only while that butyl stays plastic. Butyl in Southern California goes hard in years, not decades, and once it is hard the joint depends entirely on the mechanical fit. That is why resealing the outside of a vintage seam so rarely works: you are painting over a joint whose sealing mechanism has already been consumed, and the water path is inside the lap. > **note:** If a vintage coach still leaks after two rounds of exterior sealant, the seam needs opening. There is nothing left in the joint for a third bead to help. ## The belt rail decides whether a coach is viable On a timber framed coach the belt rail is the horizontal member where the upper and lower sidewall sheets meet, and it ties the wall to the floor. It has been receiving every drop of water that ran down that side of the vehicle since the coach was new. When we assess one of these, the belt rail is the first thing we probe, because it determines whether the project is a repair or a rebuild. The honest conversation happens here. A coach with sound belt rails and localised rot is a straightforward long project. A coach with belt rail failure along both sides has effectively lost the connection between its walls and its floor, and the number stops being a repair estimate and becomes a restoration budget. We say which one it is before anybody spends. 1. Probe the belt rail from inside at every window corner and door post 2. Check the floor edge where the sidewall lands, front to back 3. Map the rot before pricing rather than opening and discovering 4. Decide repair or rebuild with the owner, in writing, up front ## Parts that do not exist get made There is no supplier catalogue for a 1976 sidewall panel, a cast window surround or a stamped vent frame. The fabrication department is not an upsell on these coaches, it is the only path. We take patterns from the original part where enough of it survives, form new material on the brake, and match the original rivet pitch and pattern so the repair does not announce itself. Occasionally the right answer is adapting a modern component and reworking the opening to suit, especially for windows where a functioning modern unit beats a cracked casting. We put that choice to the owner explicitly, because on a vintage coach originality and usability sometimes point in different directions. ## Sixty years of other people's repairs Every vintage coach carries an archaeology of previous fixes. Steel screws in aluminum, stainless rivets next to aluminum ones, plated washers, roofing sealant over a structural seam, a patch riveted over a patch. Each dissimilar metal contact is a galvanic cell, and in coastal air those cells eat the panel outward from the fastener rather than inward from the surface. Part of any real restoration is standardising the fasteners. We remove what does not belong, isolate what has to stay, and use compatible material for everything we install, because a beautifully refinished panel with steel screws in it will bloom again within a few seasons. ## Rates, and being straight about the number Body, structural and fabrication work bills at $210 per hour with body supplies at $5 per body hour and paint supplies at $55 per paint hour. Aluminum polishing sits in the detail department at $95 per hour. Assessment is $285 per hour with a one hour minimum, credited in full against an authorized repair. The reason we push for a paid assessment on a vintage coach is that a guess here is worse than useless. The difference between localised belt rail repair and full sidewall reconstruction is a factor of five, and it cannot be seen from outside. A documented assessment lets an owner decide with real information rather than optimism. ## Who brings vintage coaches here Enthusiasts, mostly, and they generally know the coach better than any document does. The recurring situation is an owner who has been maintaining a coach carefully for years and has now found something structural, and who wants a straight answer about whether the vehicle is worth the work rather than a sales pitch in either direction. The other group is inheritance: a coach that sat under a tarp for fifteen years and has come to a family member. Those need assessment before anything else, because what is visible and what is structural have diverged completely. Rancho Santa Margarita owners towing or driving one of these in should plan a slow route rather than the freeway. ## Questions and answers ### I have sealed my old coach seams twice and it still leaks. Why? Because the sealing mechanism inside the joint is gone. A vintage lap seam works by squeezing butyl tape between two sheets. Once that butyl has hardened, the water path runs inside the lap where no exterior bead can reach it. The seam has to be opened, cleaned and re-bedded with new material. ### How do I know if a fifty year old coach is worth restoring? The belt rail answers it. That is the horizontal member where the sidewall sheets meet and it ties the walls to the floor. Localised rot with sound rails either side is a long but straightforward project. Failure along both sides means the walls have lost their connection to the floor, which is a rebuild budget. ### Why will my rivets not stop weeping even after resealing? The holes have elongated. A rivet seals by filling its hole under tension, and after decades of thermal cycling the hole is no longer round, so the rivet cannot bear evenly. Water enters along the shank, inside the panel, which is why sealant over the head changes nothing. The seam needs re-fastening. ### What happens when a part for my classic coach is not made anymore? We make it. Patterns come off the original where enough survives, new material is formed on the brake, and we match the original fastener pitch so the repair does not stand out. Where a functioning modern component beats a cracked original casting, we say so and let you choose originality or usability. ### Does it matter that a previous owner used steel screws? Yes, considerably. Steel in aluminum is a galvanic cell, and in coastal air it corrodes the panel outward from the fastener rather than inward from the surface. Standardising fasteners is part of any real restoration, because refinishing a panel that still carries dissimilar metal fasteners just delays the same bloom. ### Do I need an appraisal to insure a restored classic coach? Effectively yes. Actual cash value on a fifty year old coach bears no relation to what a restored example is worth, so a modest claim gets declared a total loss. An agreed value policy backed by a current appraisal is what keeps a repairable coach repairable when a claim is filed. --- Source: [OCRV Center](https://ocrv.me/vehicles/rvs-and-motorhomes/vintage-classic-rv-repair/). Last verified 2026-07-29.