Triumph Stag Bodywork and Rust

1. Why the Stag rots

The Stag was built to a price at the beginning of the 1970s, and like most cars of its era it was not engineered to survive fifty years. Water collects in the seams between panels, in double-skinned areas like the front wheel arches, and wherever a drain hole can block and let it sit. The decorative chrome trim is held on by plastic clips pushed into holes drilled in the bodywork, and those holes quietly rot out behind the trim where nobody looks. None of this makes the Stag unusually bad, it rusts about as readily as its contemporaries, but it has its own well-known hot spots, and one important quirk: cars built from 1974 onward tend to rot worse than earlier ones, because Triumph switched to a poorer sheet-steel supplier. It is worth knowing which side of that change your car falls on.

2. The structural areas

Some Stag rust is expensive but cosmetic. This is the rust that is neither. These areas carry the car's structure, affect its MOT and its safety, and are where a cheap Stag quietly becomes an expensive one. Check them first and check them hardest.

• The sills. The single most important structural check on a Stag. The sill is a complex, multi-layer structure, and a proper outer sill runs the full length of the car behind the front wing, which is why doing the job correctly means removing the welded-on front wing rather than patching from outside. Rust here does not stay put: it spreads into the floors and the chassis outriggers. Two warnings. Beware stainless steel oversills clipped or bonded over the original, they hide rot rather than cure it and should be lifted to see what is underneath. Sills done badly, without bracing the shell, also let the body twist, so check the door gaps and how the doors shut. A full, correct sill repair can run to four figures a side.
• The chassis outriggers. There are two outriggers on each side, carrying the body on the chassis. The front ones tend to go first, and the rust then spreads into the sills and floorpans. The main chassis itself is fairly robust, so it is the outriggers, not the chassis rails, that need the hard look.
• The floors and footwells. Front floorpans and footwells collect water and rot, often as a consequence of failing sills or blocked drainage. Lift the carpets to check rather than trusting a clean-looking cabin.
• The A-posts and B-posts. The bases of both rot, and repairs here are fiddly and costly because of the structure they carry and the panels around them. On a convertible with no roof to stiffen the shell, sound posts matter even more.
• The scuttle and windscreen surround. The scuttle and the screen surround are water traps, and corrosion here is both structurally important and awkward to put right. Rust bubbling at the base of the screen is a warning of bigger trouble behind.
• The rear suspension mountings. The rear strut tops and subframe mountings carry suspension loads, so corrosion there is a safety matter, not a cosmetic one. Check them along with the boot floor they sit near.

3. The cosmetic and panel areas

This rust costs money to put right but does not, by itself, threaten the car's structure, and most of these panels are available off the shelf, which is one of the genuine pleasures of Stag ownership.

• Wings, front and rear. Both rust, the leading edge of the rear wing especially. Remember the front wing has to come off to do the sill properly, so the two jobs often go together.
• Valances and front panel. The front valance and the panel behind the headlights, plus the seams where the front wings meet it; and at the back, the rear valance and the seam between the rear wings and the panel ahead of the boot.
• Wheel arches. The front arches are double-skinned and trap water. Watch the seams between inner and outer arches, front and rear.
• Door bottoms. They corrode from the inside out, so a tidy-looking door can be rotten along its lower edge. Check the drain holes are clear.
• Boot floor. Rots out, along with the trailing edge of the boot lid and the rear edge behind the chrome trim. Lift the boot mat and, if you can, the rear seat cushion.
• Battery tray. Trapped acid and water rot the tray. Take a look beneath the battery.
• The hard top. If the car has one, it is full of rust traps of its own. Check around all its edges, and that it and the car have aged together.
• The chrome-trim clip holes. The holes drilled for the trim clips rot from behind, out of sight. Bubbling under a strip of brightwork is the tell.

4. How to read a Stag body

A quick, ordered way to assess any Stag's body.

• Start with the panel gaps and how the doors shut. Even, consistent gaps and doors that close cleanly suggest a straight, un-twisted shell. Poor gaps hint at bad past sill or structural repair.
• Carry a magnet. It finds filler over the valances, the boot-lid edge, the boot floor, the wing seams and the hard top.
• Lift what you can. Carpets for the floors, the boot mat and rear cushion for the boot floor and rear structure, and any stainless oversills for the real sills beneath.
• Check the drain holes are clear, at the sills, doors and screen surround, because a blocked drain is where the next patch of rust is starting.
• Assume the worst about bubbles. A small blister on the surface is usually a larger hole underneath. Price accordingly.

For a full pre-purchase inspection see the Buying Guide.

5. What it means for buying and restoring

Two honest truths follow from all of this. First, on a Stag the quality of previous bodywork matters more than almost anything else, because so many have been restored and not all well. A car with fresh, correct structural work is worth far more than one hiding old sins under filler and oversills. When you view a restored car, ask what was done to the sills and outriggers, and by whom.

Second, a rusty Stag is often a worse buy than a sound one at twice the price. Structural rust is labour-intensive to cure properly, the body can hide a great deal, and the bills mount quickly, so a cheap car needing sills, outriggers and floors can cost more to put right than a good one costs to buy. The survival rate is decent and there are plenty for sale, so patience pays: buy the best body you can and spend on the mechanicals afterwards. The good news is that panel availability is strong and the specialist support is excellent.

6. Keeping rust at bay

If your Stag is sound, keeping it that way is mostly about water.

• Keep every drain hole clear, at the sills, doors, screen surround and boot.
• Do not let the car sit wet. Dry, ventilated storage does more for a Stag body than any treatment.
• Treat the cavities. A proper cavity wax through the sills, box sections and doors is cheap insurance on a car this prone to trapped-water rust.
• Deal with bubbles early, while they are still small and cheap, rather than waiting for the MOT to find them.
• Store the hard top somewhere dry and check it over, since it rusts whether it is on the car or not.

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