Bus Conversion Repair for Prevost and MCI Coach Shells

An intercity coach shell is built as a single welded structure. The floor grid, the side pillars, the roof bows and the riveted skin panels all share the load, which is how a forty five foot vehicle can be that stiff and that quiet. There is no ladder frame under it and no separate body sitting on top.

So the ordinary categories break down. On a motorhome we can usually say a panel is cosmetic and a rail is structural. Here the panel is structural, and a deep dent has locally buckled a pillar or a longitudinal behind it. That is why we open panels on these coaches when a motorhome shop would fill and paint.

Owners hear stainless and assume the problem does not exist. It does, it just happens slowly and in the worst possible location. The skeleton members behind the wheel arches live in permanent road spray, and any coach that ran a first career in a state that salts its highways carried that salt into those cavities for years.

The corrosion is inside a closed structural member, so nothing is visible from outside and nothing shows on a walk around. We look for it when a coach is in for anything adjacent: a bay door that has moved, a skin panel coming off, suspension work that gives access. Finding it early is the difference between a member repair and a section replacement.

1. Establish the coach's first career and operating region if known
2. Inspect skeleton members whenever a panel or arch liner is off
3. Sound and probe rather than relying on a visual check
4. Document findings even when no repair is authorised yet

Prevost and MCI delivered a shell with a driveline, air systems and glass. Everything an owner actually lives in came from a coachworks: Marathon, Liberty, Featherlite, Millennium and others, each with their own engineering, their own structural details and their own decade of practice. Two identical XL shells converted five years apart can be very different vehicles inside.

So we ask who converted it and when before we quote anything structural. A slide room reinforcement detail, a bay tank mounting or a roof penetration for an air unit all reflect that converter's approach, and repairing them correctly means understanding the original intent rather than assuming a factory standard.

Both start as buses and there the similarity ends. A converted intercity coach is a monocoque stainless shell with a professionally installed interior, a value in the hundreds of thousands, and repairs that are structural by nature. A skoolie is a body on frame school bus with ribbed steel sides bolted to a truck chassis and an owner built interior.

The work, the budget and the owner are all different. We keep them on separate pages because sending a skoolie owner to a monocoque page wastes their time, and because pricing a converted Prevost against a school bus build produces a number that helps nobody.

A conversion finish is layered history. The shell may have been painted at the coach plant, then again at the coachworks, then possibly repaired by two shops since. Ten or more layers is normal, hand laid graphics are normal, and different panels received different preparation two or three decades ago.

The consequence is that no single reading describes the coach. We read each panel adjacent to the repair separately with a spectrophotometer, spray let down panels, and check them in daylight as well as under booth lighting. On a coach with a wrapping graphic, painting in one booth session is the only way the result stays consistent.

Body, structural and paint work bills at $210 per hour with $55 paint supplies per paint hour and $5 body supplies per body hour. Mechanical and electrical work is $260 per hour, and measured structural assessment is $285 per hour with a one hour minimum credited against an authorized repair.

Owners are typically long term coach people, often on their second or third conversion, and entertainer coaches come in from operators who need a firm out date rather than the lowest number. Rancho Santa Margarita owners take the 241 to the 91 for a forty five foot coach with a tag axle, which is the only approach we recommend at that length.

This is exactly what our building was sized for. A 45 foot converted coach at around twelve feet ten over the roof units goes through the sixteen foot doors and paints whole in the sixty foot booth, which matters enormously here because a conversion graphic wraps continuously and cannot be joined mid flank. At 54,000 lb the coach stays on the slab on its own air suspension, never on a lift, and skeleton work behind a wheel arch is done at floor level with the coach supported on its own air bags at set ride height.