Class A Gas Motorhomes Repair for West Covina

Why the front cap cracks at the windshield corners

The molded fiberglass front cap on a gas Class A has a large rectangular hole cut in it for the windshield. Every corner of that opening is a stress riser. The cap is bonded and bolted to the house at its perimeter flange, and the house is bolted to the F53 rail through rubber isolators. When the isolators age and the house begins to move a few extra thousandths against the frame on every driveway transition, that movement has to go somewhere. It goes into the corners of the windshield opening.

The first sign is a hairline in the gelcoat, usually running up and out at roughly 45 degrees from the upper corner. Owners often mistake it for a scratch. Within a season it lengthens, opens, and starts to hold dirt, and eventually it goes all the way through the laminate. At that point the windshield gasket loses its backing on that corner and water begins tracking down the inside of the A pillar.

Repairing it means grinding the crack out in a V, back to sound laminate, well past the visible ends. We lay in new glass on the back side wherever access allows so the repair carries load instead of just filling a groove. Then the front face is relaminated, faired, high build primed, blocked and refinished into the cap. Filling the crack from the outside with body filler and shooting color over it is what a previous owner usually did, and it is why the same crack is back in the same place.

The permanent part of the fix is upstream. If the body mounts are shot, the cap will crack again. We check mount condition and hardware torque as part of any cap crack repair on an F53 coach, because otherwise you are buying the same repair twice.

Ford F53 body mounts and the movement they allow

The F53 is a straight ladder frame designed to be a foundation, not a stressed member of the house. The RV builder sets a steel outrigger structure on the rail and isolates it with rubber pucks or blocks at intervals down both sides. New, those isolators absorb the frame twist that happens every time one wheel drops into a gutter. Compressed and hardened, they pass that twist straight into the laminated house.

Symptoms show up in ways that do not look like a chassis problem. An entry door that used to latch with a push now needs a shove. A basement bay door that was flush now sits proud at one corner. The slide out that used to seal evenly now shows daylight at the top outboard corner when it is run out. A driver side windshield that develops a slow leak on the same corner every rainy season.

In shop we put the coach on level ground, unload the suspension where it needs to be unloaded, and inspect every mount for cracked rubber, elongated bolt holes, missing hardware and corrosion at the outrigger. Mount replacement is straightforward work on most F53 layouts. Elongated or torn outrigger brackets are a welding and fabrication job, and they are more common on coaches that have carried a heavy rear mounted rack or towed at the top of the rating for years.

Doing the mounts without addressing what the movement already broke leaves you with a quiet coach and a cracked cap. Doing the cap without the mounts leaves you with a cracked cap again. We price both and let you decide the order, but we do not pretend they are unrelated.

Basement bay doors that sag, bind and stop sealing

Gas Class A coaches carry most of their storage in pass through and side bays below the floor line. Those doors are large, they are heavy, and on most builds they hang from a continuous piano hinge or from gas strut assisted upper hinges with a compression bulb seal around the frame. Three things go wrong. The hinge elongates its screw holes in the door skin, the strut loses gas and stops holding the door up, and the bulb seal takes a set so the door closes onto a flat piece of rubber that no longer springs back.

A sagging bay door does more than annoy you. It stops compressing the seal at the top edge, so road spray gets in and the bay floor stays wet. Bay floors are usually a thin laminated deck, and once they stay wet they soften, then the bay walls follow. We have opened plenty of bays where the visible problem was a droopy door and the real problem was eighteen inches of rotted deck under the generator slide.

The repair depends on what is actually worn. Sometimes it is new hinges with backing plates so the fasteners pull against metal instead of against a thin skin. Sometimes the door frame itself is racked and needs to be squared and reset in the opening. Sometimes the door skin has delaminated from its foam core, which shows as a wavy face and a door that feels floppy when you lift it, and that door gets rebuilt or replaced.

We also replace the bulb seal as a matter of course when a bay has been leaking. A new seal against a door that still does not sit square just moves the leak to the other corner.

• Continuous hinge screw holes elongated in a thin door skin
• Gas struts that no longer hold the door open or pull it closed evenly
• Bulb seal compression set that leaves a gap at the top edge
• Racked door frames in the sidewall opening after a body flex event
• Delaminated door skins that wave and feel soft when lifted
• Soft or rotted bay floor decking under a long standing leak

Two piece windshields, gaskets and the leak that follows a chip

Most gas Class A coaches use a two piece windshield with a center divider bar. Each half sits in a rubber gasket that seats into the fiberglass cap opening, with a locking bead or a filler strip that tensions the gasket against the glass. That system works well as long as the cap opening is straight and the gasket is still elastic. Once the cap has cracked at a corner, or the opening has racked, the gasket cannot maintain even pressure and water finds the low spot.

A rock chip accelerates it. Chips on RV windshields spread faster than on cars because the glass is large, the openings flex, and the coach parks in direct sun where the glass sees a large temperature swing across its own surface. A crack that reaches the edge of the glass unloads that corner of the gasket entirely.

When we replace RV glass we treat the opening first. The cap flange gets inspected for cracks and for previous filler, the gasket channel gets cleaned back to gelcoat, and any damage in the flange gets laminated before glass goes near it. New gasket, new filler strip, and a controlled water test afterward. If the divider bar seal has been leaking, that gets addressed at the same time, because it is the single hardest place to seal after the fact.

Owners in West Covina often ask whether they can drive a cracked windshield down to Yorba Linda. Usually yes if the crack is not in the driver's primary sight line and not fully spanning the glass. Call (949) 799-3387 and describe the crack before you decide, and take the 60 to the 57 to the 91 rather than a rough surface street route.

Sidewall delamination on a gas coach and how it is repaired

Delamination on a Class A gas coach usually starts in one of three places: above the slide out opening, along the roof to sidewall seam on the driver side, or behind the awning rail. All three are places where a fastener or a seam gives water a way into the laminate. Once water is between the filon skin and the foam core, the adhesive bond releases and the panel begins to move independently of the structure behind it.

The early symptom is subtle. You press the sidewall with a flat palm on a warm afternoon and it moves a little where it should be rigid. Later it becomes a visible bubble or a long wave that catches the light, and it always looks worse in the afternoon because heat expands the trapped air and moisture.

Repair method depends on how far it has gone. A contained area can be treated by injecting adhesive through carefully placed access points and vacuum clamping the panel flat while it cures. That works when the core is sound and dry. When the core is wet, crushed or rotted, injection just glues a bad panel to a bad core. In that case the outer skin gets cut back to sound material, the core is replaced, and new skin is bonded in with the seam positioned where the finish repair can hide it.

The leak comes first in either case. We locate and correct the water entry before any laminate work, because a rebonded panel over an active leak is a repair with a countdown on it. On a gas Class A that usually means resealing the roof edge, resetting the awning rail with new backing and butyl, or rebuilding the slide opening flange.